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18.02.2021, adminThese lightweight canoes might really good skech used to transport complicated load or the series of passengers. In all luck substantially a many secure vessel we can find for the dimensions as well as design. Greatfully note which this pattern was tender by a "one piece wonders" organisation during Yahoo .
All libretti and programs of works performed on the stages of the Imperial Theatres were titled in French, which was the official language of the Imperial Court, as well as the language from which balletic terminology is derived.
List of acts, scenes tableaux and musical numbers, along with tempo indications. Numbers are given according to the original Russian and French titles of the first edition score , the piano reduction score by Sergei Taneyev , both published by P. The suite was first performed, under the composer's direction, on 19 March at an assembly of the Saint Petersburg branch of the Musical Society. The outline below represents the selection and sequence of the Nutcracker Suite made by the composer.
The Paraphrase on Tchaikovsky's Flower Waltz is a successful piano arrangement from one of the movements from The Nutcracker by the pianist and composer Percy Grainger. The pianist and conductor Mikhail Pletnev adapted some of the music into a virtuosic concert suite for piano solo:. Many recordings have been made since of the Nutcracker Suite , which made its initial appearance on disc that year in what is now historically considered the first record album.
Because of the ballet's approximate hour and a half length when performed without intermission, applause, or interpolated numbers, it fits very comfortably onto two LPs. Most CD recordings take up two discs, often with fillers. An exception is the minute Philips recording by Valery Gergiev that fits onto one CD because of Gergiev's somewhat brisker speeds.
With the advent of the stereo LP coinciding with the growing popularity of the complete ballet, many other complete recordings of it have been made. There have been two major theatrical film versions of the ballet, made within seven years of each other, and both were given soundtrack albums.
Neither Ormandy, Reiner, nor Fiedler ever recorded a complete version of the ballet; however, Kunzel's album of excerpts runs 73 minutes, containing more than two-thirds of the music. The music is played by the Royal Scottish National Orchestra. In Dance Magazine printed the opinions of three directors.
Ronald Alexander of Steps on Broadway and The Harlem School of the Arts said the characters in some of the dances were "borderline caricatures, if not downright demeaning". He also said some productions had made changes to improve this.
In the Arabian dance, for example, it was not necessary to portray a woman as a "seductress", showing too much skin. Alexander tried a more positive portrayal of the Chinese, but this was replaced by the more traditional version, despite positive reception.
Stoner Winslett of the Richmond Ballet said The Nutcracker was not racist and that her productions had a "diverse cast". Some people who have performed in productions of the ballet do not see a problem because they are continuing what is viewed as "a tradition". In The New Republic in , Alice Robb described white people wearing "harem pants and a straw hat, eyes painted to look slanted" and "wearing chopsticks in their black wigs" in the Chinese dance. The Arabian dance, she said, has a woman who "slinks around the stage in a belly shirt, bells attached to her ankles".
Among the attempts to change the dances were Austin McCormick making the Arabian dance into a pole dance , and San Francisco Ballet and Pittsburgh Ballet Theater changing the Chinese dance to a dragon dance. If there were stereotypes, Tchaikovsky also used them in representing his own country of Russia.
University of California, Irvine professor Jennifer Fisher said in that a two-finger salute used in the Chinese dance was not a part of the culture. Though it might have had its source in a Mongolian chopstick dance, she called it "heedless insensitivity to stereotyping". She also complained about the use in the Chinese dance of "bobbing, subservient ' kowtow ' steps, Fu Manchu mustaches, and One concern she had was that dancers believed they were learning about Asian culture, when they were really experiencing a cartoon version.
Fisher went on to say some ballet companies were recognizing that change had to happen. Georgina Pazcoguin of the New York City Ballet and former dancer Phil Chan started the "Final Bow for Yellowface" movement and created a web site which explained the history of Wooden Magnetic Sketch Board 9g the practices and suggested changes. One of their points was that only the Chinese dance made dancers look like an ethnic group other than the one they belonged to. The New York City Ballet went on to drop geisha wigs and makeup and change some dance moves.
Some other ballet companies followed. Several films having little or nothing to do with the ballet or the original Hoffmann tale have used its music:.
There have been several recorded children's adaptations of the E. Hoffmann story the basis for the ballet using Tchaikovsky's music, some quite faithful, some not. One that was not was a version titled The Nutcracker Suite for Children , narrated by Metropolitan Opera announcer Milton Cross , which used a two-piano arrangement of the music. It was released as a RPM album set in the s. It was released on one side of a RPM disc. It was quite faithful to Hoffmann's story The Nutcracker and the Mouse King , on which the ballet is based, even to the point of including the section in which Clara cuts her arm on the glass toy cabinet, and also mentioning that she married the Prince at the end.
It also included a less gruesome version of "The Tale of the Hard Nut", the tale-within-a-tale in Hoffmann's story.
It was released as part of the Tale Spinners for Children series. That warm and welcoming veneer of domestic bliss in The Nutcracker gives the appearance that all is just plummy in the ballet world. But ballet is beset by serious ailments that threaten its future in this country The tyranny of The Nutcracker is emblematic of how dull and risk-averse American ballet has become.
There were moments throughout the 20th century when ballet was brave. When it threw bold punches at its own conventions. Afraid of scandal? Not these free-thinkers; Vaslav Nijinsky 's rough-hewn, aggressive Rite of Spring famously put Paris in an uproar in Where are this century's provocations?
Has ballet become so entwined with its "Nutcracker" image, so fearfully wedded to unthreatening offerings, that it has forgotten how eye-opening and ultimately nourishing creative destruction can be? Act I of The Nutcracker ends with snow falling and snowflakes dancing. Yet The Nutcracker is now seasonal entertainment even in parts of America where snow seldom falls: Hawaii, the California coast, Florida.
Over the last 70 years this ballet�conceived in the Old World�has become an American institution. The importance of this ballet to America has become a phenomenon that surely says as much about this country as it does about this work of art. So this year I'm running a Nutcracker marathon: taking in as many different American productions as I can reasonably manage in November and December, from coast to coast more than 20, if all goes well.
Marie falls, ostensibly in a fevered dream, into a glass cabinet, cutting her arm badly. While she heals from her wound, the mouse king brainwashes her in her sleep. Her family forbids her from speaking of her "dreams" anymore, but when she vows to love even an ugly nutcracker, he comes alive and she marries him. From Wikipedia, the free encyclopedia. For other uses, see Nutcracker disambiguation. Ballet by Pyotr Ilyich Tchaikovsky. Main article: List of productions of The Nutcracker.
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For a comprehensive list of stage, film and television adaptations, see List of productions of The Nutcracker. New Haven: Yale University Press. Crain's New York Business. Retrieved 3 November The New York Times.
Retrieved 4 November Archived from the original on 16 March Retrieved 10 December Archived from the original on 10 December Retrieved 18 December Oxford: Oxford University Press. Archived from the original on 17 September Retrieved 7 January The Times. Archived from the original on 4 March Retrieved 3 February The Kennedy Center. The John F. Kennedy Center for the Performing Arts.
Archived from the original on 8 July Retrieved 15 November London: Playbill Video. Doll Dance. Moscow, Russia: Moscow Ballet. The Rat King Appears. Snow Pas de Deux. Dresden, Germany: SemperOperBallett. Russia: Perm Opera Ballet Theatre. The Nutcracker � Arabian Divertissement. Pacific Northwest Ballet. The Nutcracker � Tea Chinese Dance.
Mariinsky Ballet. Boston Ballet. The Nutcracker � Mirlitons Divertissement. New York City: Lincoln Center. Nutcracker Flowers Excerpt. Sugarplum and Cavalier variations. St Petersburg, Russia: Ovation. Dance Wooden Magnetic Sketch Board Resolution of the Sugarplum Fairy. New York City: Ovation. Encyclopaedia Britannica. The Music Alliance. Retrieved 20 January Chaykovsky Centralized Library System.
Archived from the original on 24 October Retrieved 14 December Yale University Press. ISBN Retrieved 12 December Barcarole from The Seasons 2. Lensky's aria from Eugene Onegin 4. Serenade for Strings Waltz 5. Ostrovsky The Snow Maiden 6. Archived from the original on 12 January Artoteka of Food. Retrieved 4 December The Nutcracker ". Retrieved 7 June Tchaikovsky: The Final Years, London, ; corrected edition p. Retrieved 1 July Susan Kuklin. Archived from the original on 11 June Kirkus Reviews.
The Oakland Press. Retrieved 1 October Dance Magazine. Retrieved 2 October Retrieved 3 October Archived from the original on 11 July Retrieved 23 October Tchaikovsky on the new Madame X album] in Russian.
Rossiyskaya Gazeta. Archived from the original on 2 September Temperature and Resistance using nichrome wire - Part 1 Here's an extract from my textbook about resistivity and temperature:. Like many physical properties, resistivity not only depends on the material involved but also on the temperature. The resistivity of pure metals increases linearly with temperature because a temperature increase causes the lattice ions to vibrate with greater amplitude.
This increases the likelihood of electron collisions and decreases the current through the conductor. This can make a good EEI despite the relationship being so well known.
The problem with changing the temperature of the wire is that if you use a water bath you may have to wind the wire on to a spool so that it doesn't short circuit on itself. Another way is to insulate the wire is with electrical tape or masking tape. That's what the girls at Our Lady's College, Annerley, did:.
The other problem is that if you measure the resistance by impressing a volatge across the wire and measuring the current, you will get Joule heating. You will need to be careful about what voltage you use and perhaps try a few to see what effect it is having. Great source of errors for discussion. You could also twist the wire into a loose coil without the turns touching to see if there is an interference from one turn on the next. Because the change in resistance is not large you need to choose your meters and scales with care.
If you have a voltmeter that has a full scale deflection FSD of 1V then the wire should give a current of about 40mA. This will fit nicely on an ammeter with a FSD of 50mA. In the photo above the girls have chose to use the FSD of mA range as their current was 55mA and just off the 50mA scale. It is all a balance of wire length and voltage so that the readings are close to FSD. Temperature and the resistance of nichrome wire - Part II As mentioned above resistance in wires is difficult to measure accurately because most metal resistance is too low to accurately measure by standard means ammeter and voltmeter.
It should be possible to do it accurately with a Wheatstone Bridge, but if using wire with low resistance eg copper, aluminium, steel you may find issues with the resistance of connectors being significant. However, using something like nichrome should work OK. A jug element is a simple way to experiment with nichrome. Students' results show that the element is made of 0. In an EEI you would have to look at resistivity, temperature coefficients of resistance and why - at an atomic level - resistance changes.
The bigger the temperature change the better. Physics Co-ordinator Peter Finch from St Joseph's College, Gregory Terrace, Brisbane, said that the results from such experiments are generally excellent if the experiment is done properly. He makes this suggestion:. There is one possible downside and that is the measurement of resistance.
If you do the preparation properly, you could get away with one microohmeter for a week if you have say 40 students, but be prepared to work before school and at lunch. For my eighty [Year 12] students a good number will do the resistance EEI I use two microohmmeters for two weeks.
There is an alternative to the microohmmeter and that is a set up using a Wheatstone Bridge. I did a comparison with the Wheatstone Bridge and the microohmmeter and found remarkable accuracy over a wide range of resistances. From memory it was not particularly accurate over the lower range of say 1 to microohms. Temperature and the resistance of wire - Part III One other way to get a reasonable resistance change from copper wire is to use a long length of it.
Three of my Year 12 Physics girls Georgia, Shannon and Georgina at Moreton Bay College made up coils of copper wire on cotton-reels in an experiment about guitar pickups. In one case they wound a coil of turns of 0. When they had finished I used it for an experiment on resistance and temperature see below. They didn't know I took it but it works well. I connected it to a multimeter set to measure resistance. I placed it in a beaker on a hotplate, with a lid of polystyrene, and added a thermometer through the middle of the spool.
Over the next 30 minutes it dropped back to room temperature and as it did so I took measurement readings. Here's my setup and graph. The girls didn't see me do it as they were busy writing up their EEIs; well some were - the rest were complaining about having five assignments to do over the holidays.
I know this could be greatly improved - but it seems to work. Storing charge in a home-made capacitor Capacitors are quite simple things really: two sheets of metal foil separated by a thin sheet of paper or plastic.
They are used to store electric charge. However, they are absolutely fundamental to most electrical devices from mobile phones, radios, motors, computers and so on. Their properties have been known for a few hundred years but new developments happen all the time. For instance 18 year old Eesha Khare of California developed a supercapacitor that can recharge a mobile phone battery in less than a minute.
Typically, the dielectric thickness is varied by using increasing numbers of sheets of paper or plastic whatever dielectric materal you choose. It seems that the air between the sheets confounds matters. Measure the capacitance of a home-made capacitor using a digital multimeter with capacitative measurement and vary the number of sheets of dielectric. Then repeat but try increasing the pressure on the plates by adding increasing weight brass masses or house bricks and see what that does.
Here's the clever part. Instead of just using multiple layers of plastic as the dielectric, what you could do is buy various thicknesses of the same sort of plastic. That way there is no air gap and you may be able to show that the results are more like you'd expect and what this means about the idea that air is an issue.
Capacitors and heating water If you are into electricity and want a bit of danger, this EEI may be for you. It looks at the energy stored in a capacitor being released to heat water. Capacitors can store charge so they can be a source of electrical energy.
This energy may be released slowly or quickly depending on the resistance of the load. Care must be taken when touching capacitors because you can't tell if they are charged simply by looking at them. Although they may be disconnected from a supply they may still retain a charge, and this stored energy can give you a serious shock! This happened to me when I was taking apart a camera flash.
Set up the circuit shown below and charge the capacitor by connecting it across a battery. You will need to work out how to do this. It takes a time of 5T to fully charge the capacitor. You could experiment with the heating coil but a short length of nichrome wire may work. Keep the volume of water small so the temperature rise is reasonable. Just watch out for the heat losses into the wire, the container, the air and the sensor.
One question is what is a suitable size for the capacitor. You need enough energy stored in it so you can get a reasonable temperature change in the water.
A F 2. That is reasonable if your temperature sensor is accurate enough. You can get higher voltage capacitors eg 32V but you have to wonder how you'd charge them in the lab with a lot of batteries in series. Remember that the stored charge can be quite high and dangerous. Talk to your teacher before you do any trials, and don't hack open an old TV to get the capacitor out as it could still carry a lethal charge.
An excellent EEI can be done on graphite pencil "leads". They are not really lead Pb metal but a mixture of powdered graphite and clay. They do come in different hardnesses and diameters, but they are brittle so it is sometimes problematic getting a good electrical connection.
Physics teacher Alan Whyborn at Urangan State High School, Queensland, makes this suggestion for an EEI: "You can qualitatively examine the effect of temperature by collecting a set of readings in the air at different voltages V being the independent variable.
But note, the leads will get red hot. You could collecting another set of readings under water. If you get a negative temperature coefficient opposite to metals then start thinking that perhaps the thermal energy of the electrons is enough to put more electrons into a conduction band.
Over to you. Resistance of different types of graphite Carbon composition resistors are made from a molded carbon powder that has been mixed with a phenolic or wax binder to create a uniform resistive body. It is then surrounded in a insulating case after attaching end leads. You could model a resistor using graphite 'lead' pencils. The table below sets ou the composition of the various types of pencils:. If they heat up then you will have to control the temperature variable but perhaps you could do that by immersing the "leads" in water.
For each type of pencil they used three different lengths as well so they could check if R was proportional to L to eliminate that as an artefact of the experiment. I won't give away all of their results but for 2B and 4B pencils they obtained resistances of 4. It is an "A" level and shows you what a teacher would look for at this level. Click here to download pdf.
Resistivity of Play-Doh Here's a good EEI if you like playing with Play Doh and want to investigate the properties of ohmic materials and resistivity while having fun. Play-Doh is a modelling compound used by young children for art and craft projects at home and in school.
It was first manufactured in Cincinnati, Ohio, U. It is composed of water, a starch-based binder, a retrogradation inhibitor, salt NaCl , lubricant, surfactant, preservative, hardener, humectant, fragrance, and color.
A petroleum additive gives the compound a smooth feel, and borax prevents mold from developing. Applying a voltage difference across a conductor and measuring the current flowing through a resistor allows the resistance of the conducting material to be determined. From this you can calculate the resistivity if you know the length of the sample and its cross-sectional area.
A good method would be to get a plastic tube eg electrical conduit and drill a few holes in the side. Then fill it with Play Doh and poke electrodes in the ends. As the V and I are increased, you can measure the voltage drop across two voltmeter probes placed at a measured separation in the Play Doh. I tried an external voltages from 0. I found resistivities of about 0. You could investigate the conditions and reason under which it becomes non-ohmic.
If you want to see how the resistivity changes over the day, the ends need to be sealed with cling-wrap or something else to stop it drying out and resisting the movement of charge. You may like to try different diameters of pipes as well. It all goes towards seeing if the measurement of resistivity of this funny stuff is subject to different lengths, areas and voltages. Chris Fuse said about the time factor:. Resistance and temperature for non-ohmic sausages You can cook food by forcing an electrical current through it.
This method of cooking is known as ohmic heating and was proposed at the end of the 19th century. However, no clear conclusion has been reached with regard to the potential use of ohmic cooking in commercial meat processing. The suitability of food for ohmic heating is essentially dependent on its electrical conductivity and there are critical values below 0. Secondly, knowledge of the electrical conductivity of meat may give important knowledge about electrical safety for humans.
In this regard, determination of the electrical conductivity of a sausage maybe a worthwhile investigation. There are many problems with this though. Firstly, you may wish to know if the sausage is an ohmic resistor - by increasing V across its ends and noting the current through it. But herein lies the problem: as you increase V the sausage will warm up due to Joule heating and its resistance will thus change. You have to keep temperature constant for Ohm's Law to be checked.
That's your first problem. At each chosen temperature you could also calculate its resistivity and work out the change in resistivity with temperature knowing the length and diameter would be necessary. If you are tempted to eat the sausage when you have finished - don't. The bacteria may have had a field-day while the sausage is left warm.
Electrical conductivity of selected juices: influences of temperature, solids content, applied voltage, and particle size.
Journal of Food Processing and Engineering Making and testing a catapult - the trebuchet A catapult is any kind of device that shoots or launches a projectile by mechanical means. There are many types of catapult. Today 'catapult' describes any machine that hurls a projectile, and one example is the trebuchet.
A trebuchet is a siege engine that was employed in the Middle Ages either to smash masonry walls or to throw projectiles over them. It works by using the mechanical principle of leverage to propel a stone or other projectile much farther and more accurately than other catapults. The sling and the arm swing up to the vertical position, where usually assisted by a hook, one end of the sling releases, propelling the projectile towards the target with great force. The projectile force of the trebuchet is obtained from the gravitational potential energy of a heavy weight.
Among the various types of catapult, the trebuchet was the most accurate and among the most efficient in terms of transferring the stored energy to the projectile.
GPE of weight, length and position of arms; why do these affect range? Please note: it is all very well to make spectacular and intricate trebuchets eg carved and polished oak or pouring your own lead counterweight complete with ancient inscriptions of battles won , and it is all very well to do heaps of testing battling each others castles on the footy oval ; but unless you meet the requirements of the criteria in analysis, discussion, evaluation etc there is little hope for a good EEI grade.
Be warned! Your teacher will also be concerned about safety see " weapons " note above. You will have to get parental supervision if you are using power tools or testing it at home.
Some teachers have wisely said: the trebuchet must be small enough to fit on a school desk; the projectile should be soft, eg a softball; or the projectile should have a mass no more than a golf ball.
Teachers report some lethal trebuchets used to launched huge projectiles in the back yards of suburbia. However, there have been students who made ballista ie catapults out of paddle-pop sticks and received an "A". Extra photos can be downloaded click here. Making and testing a catapult - the mangonel A 'mangonel' is another form of catapult that relies on potential energy to provide the projecting force.
It consists of a long, wooden arm and a bucket medieval models used a sling with a rope attached to the end. The arm is then pulled back fromthe vertical. Elastic potential energy is stored in the tension of the rope and the arm. A mangonel does not release its energy in a linear fashion. The arm makes an arc portion of a circle with a radius equal to the arm's length. Therefore, the potential energy is transferred into rotational kinetic energy and to translational kinetic energy of the projectile.
The difficult question before you even start is: what will be your independent variable and how will you measure it? Home-made mangonel. The twisted rope in the middle of the base stores the elastic potential energy. Ballistic pendulum - speeds of projectiles The motion of projectiles - balls, bullets and arrows - always makes a popular EEI. One of the things you may need to measure is the speed of the projectile and this can be tricky. An old-fashioned way is to use a device called a ballistic pendulum see below.
It was invented in by English mathematician Benjamin Robins to provide the first way to accurately measure the velocity of a bullet. Once, students would do this prac using live ammunition. They would fire their guns at a wooden block suspended by a rope i.
By measuring how high the pendulum swung, they could determine the initial velocity of the bullet. Robins' original work used a heavy iron pendulum, faced with wood, to catch the bullet. Today, in university physics labs through the world they have these elaborate and costly devices for students to us.
However, the physics principles tend to get lost in the bells and whistles. I used to use an air-rifle and fire pellets into a small ball of clay. But you can't do this today in class as it is too dangerous. But you could do it with a bow and arrow, or a ball launched from a small catapult and so on. The maths is not too complex but making the apparatus work without errors is the challenge.
The simplest ballistic pendulum is just a absorbent target clay, plasticine, toilet roll, foam hanging on a single string. Robins used a length of cotton thread to measure the travel of the pendulum. The pendulum would draw out a length of thread equal to the chord of pendulum's travel.
Great idea that still works well. But if the target rotates at all when struck then some of the translational kinetic energy is transferred to rotational kinetic energy and not to gravitational potential energy.
How do you stop this? So where is the EEI in this if it is so simple? The aim is not simply to measure the velocity of a projectile ho hum - but it could be about extending or refining this idea. That's what turns a "cook-book" prac into an EEI.
You could compare this method with some other method for measuring projectile speed time-of-flight, range ; you could look at how the accuracy varies with the relative or absolute mass of the projectile and target, or its speed; or the angle through which the pendulum swings. You could look at whether four strings better than two or one; is any kinetic energy converted to heat; does the period of oscillation of the pendulum bear any relationship to the velocity it does, but how? This could be quite a remarkable EEI.
Optimise a water rocket A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel - the engine of the rocket - is usually a used plastic soft drink bottle. The water is forced out by a pressurized gas, typically compressed air. As the water is ejected the rocket's mass becomes less so less force is needed to maintain acceleration; but as the gas expands it's pressure becomes less and can provide less force. How do these competing factors affect the motion of the rocket.
You could look at height or time of flight vs initial mass of water, pressure, nozzle area, mass of rocket. Explain the physics to justify your hypothesis or will you do it by trial-and-error? A detailed examination of the maths behind water rockets has been provided by Dr Peter Nielsen from Department of Civil Engineering at the University of Queensland. Click here to download. He has also provided a rocket simulator spreadsheet to examine the factors theoretically.
Factors affecting the trajectory of a solid fuel rocket This is a popular one if you are able to get hold of rocket "motors". These forces are lift, weight, thrust and drag. The lift force acting on a rocket in flight is usually pretty small. The other three forces, however, all directly impact the maximum height the rocket can reach.
Weight is a function of how each component of the rocket is designed. The lighter the rocket is, the higher it will be able to go all else being equal. Thrust is generated by the rocket's motor. The more thrust the motor produces, the higher it will go.
However, neither of these forces is heavily dependent on the nose shape. The force that has the most effect and does vary significantly with the shape of the nose is drag.
Patrick decided to investigate nose shape cylindrical, elliptical and pointed as a factor in a rocket's performance. You can read his abstract here along with a couple of his data tables and a comment on the method. He said there were no real problems apart from some faulty launch controllers "which they replaced promptly". Click here to see the Toyworld catalogue page. Robert said that he was looking at less powerfulengines in "The Cs are spectacular but you need a large area for testingand a small amount of wind as it's likely they will go missing".
The first number after the letter represents the number of seconds of engine thrust. The second number represents the number of seconds of delay between the end of engine thrust and the reverse recovery system deployment or second stage ignition charge.
Thus a type C delivers 10 newton seconds of thrust in a six second burn, followed by a five second delay. The altimeter's data can be downloaded via a USB connection and analysed for altitude, acceleration and velocity of rocket flight. More photos from Patrick's EEI can be seen here.
A question often asked about tracking a rocket either solid propellent or a water rocket is: could you use a GPS tracking device? The issue with GPS is that it's not very fast or accurate. A Garmin GPS as used in say cycling works best when you're moving, otherwise it meanders around all over the place.
In terms of ruggedness, if it was onto grass a bit of foam padding may help. That being said - a GPS data logger would be good - something with batteries and an "event" button so you could find the start of your testing. Hydraulic Jumps in a kitchen sink When you let a tap run in a sink see below , you notice a very interesting phenomenon called 'Hydraulic jump'.
When a smooth column of water from the tap hits a horizontal plane the sink , it flows out radially. At some radius, its height suddenly rises. This is the hydraulic jump HJ. Since then, a considerable amount of work has been devoted to this question both from experimental and theoretical viewpoints. For a flow of water as in the diagram above, the radius of the hydraulic jump R j is related to a number of factors and exploring these would make a great EEI.
But you should note that the concepts are quite difficult and the maths could be a bit daunting. You could try using a burette, and making a series of nozzles for it of different diameters I just took the nozzle off.
Varying density or viscosity could be done using ethylene glycol car radiator antifreeze and diluting it with water. It has been found that surface tension has an effect so you could make up water solutions with different concentrations of detergents not too much. Measuring the velocity of the water as it spreads across the plate is very hard but can be done by high speed filming and observing the outward radial motion of micro-bubbles.
Even though the theory is difficult, you may be able to determine some simple relationships between the variables by use of graphs. I had lots of trouble measuring the flow rate of water out of the burette needed 3 hands but I think if you videoed a stopwatch and the burette as it empties you could get accurate measurements. Water discharge from a leaky bucket Whether its at hole in a dam wall or a leaky urn in the tuckshop - leaks are annoying.
But the rate of flow of water from a reservoir is obviously dependent on the height of water above the hole the 'head' and the size of the opening.
Engineers model fluid flow through an orifice so they can design the optimum combination when the flow is desirable, and the design safety devices for coping with accidents when the flow is not wanted. A great EEI can be done on this topic.
I just saw a great one by Year 12 student Steven Ettema from Brisbane Bayside State College using a bucket of water, a Pasco force meter and a computer to collect the data. His teacher Mr Ben Robson was very impressed. Steven's dependent variable was the change in weight F w of the water with time, and his manipulated independent variable was the size of the hole in the bucket see diagram below.
His development and justification of the hypothesis was breathtaking. To tantalise you I can report that is took Water discharge from a water rocket Steven's idea mentioned above can also be used to measure the change in flow rate with time from a water rocket plastic water bottle partly filled with water and pressurised.
When the stopper is removed the water jets out under gas pressure. However, as the air in the headspace expands, the pressure decreases and you would think the rate of flow gets less. All you need to do is prepare a pressurised water rocket in a water bottle, suspend the water rocket from the ceiling using a force meter to measure the weight, and the remove the stopper from the mouth.
As the water comes out the force meter will give you a reading of the weight gets less - but maybe not regularly. You could then consider changing the starting pressure or the volume of water or whatever you like. Water flow I - Poiseuille's Law The study of the flow of real fluids through tubes is of considerable interest in physics and chemistry as well as in biomedical science flow of blood in arteries and in engineering.
Engineers have to keep water moving in pipes to supply cities with drinking water, and to take waste water away. They know that the speed of the water depends on the viscosity, the diameter of the pipe, the length of the pipe and the pressure difference.
You can look this up to find out what the symbols mean. A first year university experiment is shown in the diagram below but you could do it with a Buchner Art 101 Wooden Sketch Box Easel Video flask in place of RF below and a plastic water bottle, stoppers and glass tubing. You hook up a vacuum pump to reduce the pressure in flask RF and when the valve "A" is opened water flows from jar CF through the pipe "T" into the flask RF.
By measuring the volume of water collected in a given time for a controlled pressure and tube diameter and thickness you can look at relationships. Then vary the length of the pipe, or its thickness, or the pressure, or the viscosity and so on. What a fabulous experiment for an EEI. A paper about this experiment is available from the European Journal of Physics V27 Click to download.
If you do it as an EEI please send me a photo for this webpage. Water flow II - Poiseuille's Law Another neat way of exploring the factors affecting flow rate in liquids is shown in the diagram below. It could be used in university physics. The motion sensor measures the changing height of the water column by using an ultrasound beam. These are commonly available in high school laboratories these days Vernier, DataLogger Pro etc. For high school, you could also keep pressure constant by having a small hose from the lab tap going into the top of the column and doing away with the motion sensor.
You could do it with a plastic water bottle, a stopper or two and some glass tubing. What a great EEI! A paper about this experiment is available from the European Journal of Physics V29 If you do it as an EEI be sure to send me a photo for this page.
However, not far behind were water clocks. Later named clepsydras "water thieves" by the Greeks, who began using them about BCE, these were stone vessels with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom. In a variation, the Saxons ancestors of modern-day English, Germans and Dutch would place a small bowl with a hole in its bottom in a larger container of water.
It would slowly sink as water rushed in through the hole and and finally submerge when full. The Saxons used the time it took the bowl to submerge to limit orations speeches.
There is a story that other service providers used such bowls to allocate their customer's time. These were still in use in North Africa in the 20th century. It is highly likely that there is a relationship between the diameter of the hole and the time until submergence and it won't be linear so plenty of data points. However, as water enters the hole and the bowl fills you would think it would get harder and harder for more water to enter.
Maybe, maybe not. Also, it would seem that as the cup sunk the hole would be further from the surface and thus experience greater pressure. I've seen these cups made from the plastic PVC caps they use for plumbing see below. Buy a lot, drill holes of varying diameter and Bob's your uncle. May need one drop of detergent why?
You could even use an old jam tin or something like that which may give a longer sink time. Lots of errors to talk about. She hypothesised that as the diameter of the Saxon Bowl was increased, then the sinking time would decrease when the dimensions of the bowl and density of sinking liquid are kept the same. She argued, in part, that a higher flow rate would result in a decrease in fluid pressure as per Bernoulli's theorem which states "if the fluid flows horizontally so that no change in gravitational potential energy occurs, then a decrease in fluid pressure is associated with an increase in fluid velocity.
Her graphs are as follows:. As it flows there is loss of energy due to viscous resistance with the walls of the blood vessel and this is the major source of blood pressure drop. This energy is transformed into heat. Such flow can be modelled by the use of a syphon. With a water syphon see below it seems logical that the flow rate is dependent on the height of the "loop". This is borne out by experiments. However,this is not because there is a greater weight of water being pushed up the tube because there is an equal weight of water on the other side to balance this out.
It is to do with the greater length of tube and hence the greater friction involved in the flow. Hence, flow rate Q is inversely proportional to the length of the tube.
I tried three lengths of clear PVC tubing: 50, and cm, and kept the h3 value the same at 20 cm. This gave me h1 values of My flow rates were I've plotted them below:.
But this is hardly enough fro a good EEI. For a start you'd need a lot more data points perhaps do triplicate measurements of each of five diferent heights. And you should be able to think of factors to vary besides height. There's an idea. This is of concern to environmental scientists as the erosion of soil and "crusting" is a function of their size and energy. This suggests a great EEI though. You could investigate the bounce and splash heights of a water droplet as a function of its drop height and diameter.
It seems that you do not have to worry about the droplet reaching terminal velocity before it strikes the ground as water droplets of 2mm diameter take at least 5 metres to reach terminal speed. How to measure drop diameter? If you ever do titrations in chemistry you'd know that 1 drop from a burette is said to be 0. If you treat this drop as a sphere of water you can work out its diameter. I'd let drops fall from a burette or dropper into a beaker on an electronic balance; then calculate the mass and hence volume of one drop.
To get bigger drops just cut a little bit off the tip of the plastic nozzle see above. These are disposable and are as cheap as chips. You can get them from LabPro if you are in Australia.
Measuring bounce and splash heights is another thing. Dave suggested we use a tray of water 5 cm deep and a sheet of black cardboard with a ruler attached. The splash height was obvious from the droplets on the black cardboard.
To see the bounce heights he videoed the with an ordinary camera and scrolled through the frames to see the bounce height VLC Player works okay for this. This is not necessary if you are just doing splash heights.
You can see Dave's video here. This EEI would be so much fun. A helicopter flies by means of the thrust that is created by the rotation of the blades of a main rotor that is mounted on a shaft above the fuselage of the aircraft see below.
As the blades rotate, an airflow is created over them, resulting in lift. This raises the helicopter. Newton's third law requires that the air in turn exert an equal force upward on the rotor. For a helicopter to hover, the force exerted by the rotor blade on the air must be equal to the weight of the helicopter. You decide! You're not trying to prove the formula but look for relationships between various quantities such as mass, frequency, radius, blade angle and so on.
What fun! Here's an article from The Physics Teacher that gives a bit of the theory. Lift of a flat surface in wind You may have seen the roof a house lift off in a storm. Sometimes it is the low pressure created on the top of the roof that causes it to lift off. However, with awnings and carport roofs it could be the wind lifting from underneath. What would be interesting to find out and make a good EEI is to see how the wind speed affects the lifting force of a flat roof.
Perhaps you could measure the upward or downward force on a flat surface by using an electronic balance that supports a pillar with a flat surface attached at the top, push the 'tare' button, and turn the fan on. In terms of physics theory you would need to consider Bernoulli's Principle in your investigation. There is a heap of stuff on the internet.
Just Google "Bernoulli's Principle lift of roof" and you'll see plenty of pages with examples and calculations. One that seems quite good and has a worked example is here. Lift the dependent variable DV ; 2. Wind speed 3. Area of roof 4. Angle of roof. To change wind speed you could adjust the setting on a fan off, 1, 2, 3. That would give you 4 "treatments" or data points but they are not a measured physical quantity but just someone's idea of fast and slow.
Five points would be better, so you could shift the fan away from the "roof" to make the speed lower. To measure the speed important for an EEI you could use an anemometer wind speed meter that most schools seem to have if not in Science, try Geography. It's also available for Android. It uses the microphone as a sensor and the loudness of the sound is a measure of the speed.
If you can't get steady results from the scale it may be that the weight of the device is too light and it is jumping up and down a bit on the pan. Make it out of something a bit heavier. What more to say: a simple but socially relevant investigation set in the context of houses having their roofs blown off. Loud music can cause hearing damage. The closer the source is to your ear the louder it sounds.
That's why earbud headphones can be bad for your health. This EEI looks at the relationship between loudness and distance. In essence, you just generate a fixed sound and measure its loudness or sound pressure level SPL with a microphone or as you gradually move it away from the source.
But be careful with the theory here. The sound intensity I is different to the sound intensity level L. Intensity I is inversely proportional to the square of the distance between the loudspeaker and the microphone.
Sound intensity level L is the perceived sound intensity taking the response of the human ear into account.
The response of the human ear to different intensities at fixed sound frequency is close to being logarithmic. Let's try that. Two things are necessary: 1. A source of sound. The simplest thing would to be use Audacity on your computer to generate a set frequency say Hz played through some earbud headphones well, just one earbud; hide the other one under a pillow.
Make sure you keep the sound at the same level between tests. The other thing is a sensor to measure sound pressure. Audacity can measure loudness but it doesn't calculate SPL values; it just converts the analogue input to a digital signal and assigns 0dB on the recording level meters to a certain input level, which corresponds to the maximum value of the digital signal.
So forget about that. Their results were reported in the Journal of the Acoustical Society of America V, EL : "Evaluation of smartphone sound measurement applications".
This was the only app to absolutely nail the results each and every time. It passed all four tests with flying colors. They said the microphones on the Android and Windows devices were not Wooden Magnetic Sketch Board Yellow very good but that may have changed by now. I used NoiSee which was terrific see photo below , but Noise Hunter was much much better as you could save and email the the readings and it gave you peaks, averages and standard deviations. My recommendation. A good frequency to try is 3 kHz.
This value is used because the human ear is most sensitive to frequencies in the 3. But don't quote me - get a proper reference. The distance between the loudspeaker and the sound level sensor could be varied say from 1 cm to 50 cm. It sounds close but the background noise wouldn't intrude. MBC students tested it out to 6 metres but got all sorts of background noise interferring.
I also investigated different frequencies see below. Sound intensity and distance - frequency effects examined It seems obvious that the further you are away from a loudspeaker the less loud it will sound see above. You textbook will tell you that the intensity level of a sound is directly proportional to the logarithm of the inverse square of distance from the sound source. But is this true for all frequencies or is this just a general relationship.
You can hear the thumping bass from an outdoor rock concert miles away but the higher frequencies seem to diminish quickly however, there are too many variables to make that an EEI. How does the relationship stand up over say 10 cm or 10 metres? You have to be cautious when using big distances as external sounds intrude. Here are some student results. Singing wine glass You can make a wine glass sing a pure tone by rubbing your degreased and wetted finger around the rim.
Vibrations are set up in the wall of the glass and resonance occurs in the air column. A lot of it is counter-intuitive! But is the pitch proportional to the circumference, the diameter of the glass or the amount of liquid in the glass?
Physics books give wayward opinions and you could finally work out who is right and what factors are involved. Capture the sound on a CRO and work out the frequency.
Four variations you could try are shown below. The last one has a solid column in the glass so there is less water but the same water level. Or you could compare liquids of different density or viscosity; or non-polar hexane with polar ethanol. Don't try to do too many variables or you'll run out of time. My thanks to Physics teacher Steven Anastasi from The Cathedral College, Rockhampton, Queensland: "One would expect that a singing wine glass behaves like a closed pipe, but a few simple tests challenge this fact.
For one thing, filling the glass with water would imply that the note goes up, not down. Does it? That said, the length of a wine glass is very short, so the frequency might be so high you just don't hear that note. Perhaps these days there is software available that can 'hear' well above the range of human hearing, and this would be worth investigating by doing a theoretical analysis of the frequencies expected, then searching for them with technology. Yet there remains the question of what variables influence the frequency of the singing wine glass, and testing the frequency heard is just one aspect, and a little bit simple for a thorough going physicist.
Is it the thickness of the glass? The volume of water, the height of water? Is it a coupling of the water to the glass? Is there a temperature effect? Is it predictable. Indeed, the holy grail of singing wine glasses is to arrive at a formula that predicts the frequency that might be heard, for well justified reasons.
Your object ought to be to arrive at an answer. This might be discoverable using your fancy calculator, but that is maths barely not physics. In the end you should be able to provide reasons for its behaviour, based on your personal observations, and verifiable by prediction based on equations or by trend. Well you don't - and therein lies the beauty of this for an EEI.
There is a good little article in the Physics Teacher December The reverberation time of a large hall You are probably familiar with the way some rooms echo whereas others always sound really quiet. The best measure of this acoustic property of a room is known as reverberation time.
Reverberation is the persistence of sound in a particular space after the original sound is stopped. A reverberation, or reverb, is created when a sound is produced in an enclosed space causing a large number of echoes to build up and then slowly decay as the sound is absorbed by the walls and air. The reverberation time RT 60 is the time required for reflections of a direct sound to decay by 60 dB below the level of the direct sound. The reverberation time receives special consideration in the architectural design of large chambers, which need to have specific reverberation times to achieve optimum performance for their intended activity.
This makes a great EEI. Not only can you measure the reverberation time of a number of different rooms laboratory, classroom, large lecture hall, auditorium, sports hall but you can make measurements from different parts of the room. All you need is a stopwatch, a ruler, a sound pressure sensor connected to a computer is good and something to make a loud noise.
A more sophisticated setup for measuring sound pressure level loudness is using the Audacity program on a computer. In this case you would start recording and then pop a balloon. You will see a spike on the waveform which levels off to zero as the sound dies away. Trim the waveform by deleting the quiet parts either side. Then go to "Effects" menu and select "Normalise".
Check the DC Offset box to remove offset, and enter That will reduce the peak amplitude to a managable level. In the "Audio Track" menu to the left of the wave, you can select "Waveform dB " so that the scale is now in dB instead of from 0 to Audacity sets the peak to 0dB and the middle horizontal axis to dB which is designed for working out reverberation time see below.
Just note the time elapsed from the big peak to where the line crosses the dB central line. Use a ruler as the graph should be a straight line. I added the yellow line to make the slope clear. Guitar Strings and Mersenne's Law You should be well aware that as you tighten a guitar string it's pitch sound frequency increases; and the thick strings wound with copper produce a lower frequency than the lighweight steel or nylon ones. This is the basis of Mersenne's Law: the fundamental frequency of a vibrating string is proportional to the square root of the tension and inversely proportional both to the length and the square root of the mass per unit length.
You could investigate this for yourself but the Law is only the starting point; it's no good just proving the law by using a recipe-style experiment - that's hardly the recipe for a good EEI. For some practical suggestions for this investigation go further down this EEI webpage until you hit "Guitar Pickups" where I talk about making a sonometer. I made one from a piece of pine about cm long. As far as the string goes I suggest going to a guitar shop and get a G-string as it is the thickest 0.
For the weights hanging over the end I used some from a weightlifting kit. You could start with the slotted brass masses from school up to say g but after that you really need big steel masses.
These are cheap from shops like A-Mart Sports if you haven't got any others. I'd increase the mass in 0. That will give you a tension of 4. You need a microphone and plug it into the computer sound port and use the program Audacity free to download to record and analyse the sound. Some more suggested research questions have been made by Physics teacher Stephen Pinel to whom I am most grateful:. Might there be a good reason for this? Compare and contrast the physics of a woodwind instrument e.
What differences in pitch might you expect of each instrument in changed temperature conditions? This might be considered from several perspectives - the air temperature, or the temperature of the instrument, preferably both.
You know from theory that the frequency of the woodwind instrument is related to the speed of sound, and from thermodynamics that the speed of sound in air is different when it is colder. How would this affect the note, and can you describe this with equations?
Similarly, does a guitar string 'speed up' or 'slow down' when it is cold? Does the frequency also depend on the speed of sound in air? Would a woodwind player and a guitarist have the same tuning issues if they gave a concert in a freezer? Your task is to consider this from a theoretical perspective, then test it in an experimental setting.
Variables that might be considered include whether end correction of the woodwind instrument changes against the controlled variable. Does it matter which note you are testing? Is there a connection between end correction and the note? Could you 'correct' the instrument by adding or removing the tip of the wind instrument? It produces vapour "smoke" rings about 5 cm in diameter that shoot out a few metres. They are not really smoke but are condensed water vapour clouds produced by a mist of cold alcohol vapour in the gun.
It even has a blue LED light and ray-gun sound effect. This suggests a possible EEI. I don't think you'd have much of an EEI if you just had fun with them and tried to make the biggest or fastest ring you could. You need a hypothesis about some variables that you can justify with reference to physics principles, and a means of manipulating these variables.
Instead of buying the Zero Toys Vapour Ring you would be better making your own so that the variables can be manipulated more easily. There are plenty of instructions online to choose from; but a can eg soup, canned fruit with a balloon over the open end and a circular vent in the other is a good start. When you gently flick the balloon end of your vortex launcher, a transparent ring of spinning air will shoot out of the hole you can feel it and blow out a candle metres away.
You need to make the ring visible so a smoking incense stick may help or make clouds from dry ice in water and inject into the can through a tube.
How does the hole size affect the ring? How does greater stretching of the balloon affect the ring? Good EEI variables. For more control of your variables replace the rubber drumhead with a large bass loudspeaker hooked up to a power amp driven by your computer's audio output.
This isn't really necessary to have a good EEI but if you are really keen - it could be good. Using a waveform generator like Audacity you could control of the impulse waveform applied to the vortex generator.
The waveform is a single pulse. The steep leading edge of the pulse creates the vortex. You may want to try pulses of different shapes. The loudspeaker cone should move forward quickly, then suddenly stop, then slowly return to its original position like wave 2 below. Here are some waveforms to think about. A square wave 1 will give a fast rise and should give a high velocity. The repetition rate of the square wave generator will allow you to create a train of vortices.
But you could try creating various shapes with a waveform editor as shown above. If you want to really get into the effect of the waveform on the vortex you will need an "arbitrary waveform editor" AWE where you can change the shape to your heart's desire.
Just choose the "Ramp" wave-function, set the frequency to 1. Bitscope www. Lastly, the physics of it all. You'd probably have to video the train of rings to work out their velocity.
Tuning Fork Rotation and Jet Engines If you strike a tuning fork and rotate it as you hold it up to your ear, you will hear the sound alternating between loud and soft. You should find four positions where the sound is loud, alternating with four positions where the sound is soft about 5 dB lower.
See the diagram below. This can be explained in terms of interference effects. Each tine of the fork produces a pressure wave which travels outward at the speed of sound. The compressions have a pressure higher than atmospheric pressure, while the rarefactions have a lower pressure.
At some angles the high pressure areas of the two waves coincide and you hear a louder sound constructive interference. At other angles, the high pressure part of one wave coincides with the low pressure part of the other destructive interference. That sounds logical and simple enough. However, if you sound the tuning fork at arm's length from your ear and rotate it about its long axis you will only hear two maxima and two minima not four.
These two situations are known as near-field close to your ear and far-field arm's length sounds.
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