http://www.iypt.at/en/iypt2010/problems/
1. Electromagnetic cannon
A solenoid can be used to fire a small ball. A capacitor is used to energize the solenoid coil. Build a device with a capacitor charged to a maximum 50V. Investigate the relevant parameters and maximize the speed of the ball.
2. Brilliant pattern
Suspend a water drop at the lower end of a vertical pipe. Illuminate the drop using a laser pointer and observe the pattern created on a screen. Study and explain the structure of the pattern.
3. Steel balls
Colliding two large steel balls with a thin sheet of material (e.g. paper) in between may "burn" a hole in the sheet. Investigate this effect for various materials.
4. Soap film
Create a soap film in a circular wire loop. The soap film deforms when a charged body is placed next to it. Investigate how the shape of the soap film depends on the position and nature of the charge.
5. Grid
A plastic grid covers the open end of a cylindrical vessel containing water. The grid is covered and the vessel is turned upside down. What is the maximal size of holes in the grid so that water does not flow out when the cover is removed?
6. Ice
A wire with weights attached to each end is placed across a block of ice. The wire may pass through the ice without cutting it. Investigate the phenomenon.
7. Two flasks
Two similar flasks (one is empty, one contains water) are each connected by flexible pipes to a lower water reservoir. The flasks are heated to 100C and this temperature is held for some time. Heating is stopped and as the flasks cool down, water is drawn up the tubes. Investigate and describe in which tube the water goes up faster and in which the final height is greater. How does this effect depend on the time of heating?
8. Liquid light guide
A transparent vessel is filled with a liquid (e.g. water). A jet flows out of the vessel. A light source is placed so that a horizontal beam enters the liquid jet (see picture). Under what conditions does the jet operate like a light guide?
9. Sticky water
When a horizontal cylinder is placed in a vertical stream of water, the stream can follow the cylinders circumference along the bottom and continue up the other side before it detaches. Explain this phenomenon and investigate the relevant parameters.
10. Calm surface
When wind blows across a water surface, waves can be observed. If the water is covered by an oil layer, the waves on the water surface will diminish. Investigate the phenomenon.
11. Sand
Dry sand is rather 'soft' to walk on when compared to damp sand. However sand containing a significant amount of water becomes soft again. Investigate the parameters that affect the softness of sand.
12. Wet towels
When a wet towel is flicked, it may create a cracking sound like a whip. Investigate the effect. Why does a wet towel crack louder than a dry one?
13. Shrieking rod
A metal rod is held between two fingers and hit. Investigate how the sound produced depends on the position of holding and hitting the rod?
14. Magnetic spring
Two magnets are arranged on top of each other such that one of them is fixed and the other one can move vertically. Investigate oscillations of the magnet.
15. Paper anemometer
When thin strips of paper are placed in an air flow, a noise may be heard. Investigate how the velocity of the air flow can be deduced from this noise?
16. Rotating spring
A helical spring is rotated about one of its ends around a vertical axis. Investigate the expansion of the spring with and without an additional mass attached to its free end.
17. Kelvins dropper
Construct Kelvin's dropper. Measure the highest voltage it can produce. Investigate its dependence on relevant parameters.
Monday, October 26, 2009
Sunday, October 25, 2009
Saturday, October 24, 2009
Measurment
http://www.thestudentroom.co.uk/wiki/Revision:Measurement
1.1 Standards of measurement
1.1.1 : Fundamental and derived units
Fundamental units are, in general those which can't be expressed in terms of others (there are exceptions). Mass, length, time, electric current (this is defined in terms of force between wires, but is fundamental in terms of electric circuits). The newton is a derived unit, because it is defined as the force required to accelerate 1kg at 1 ms-2. Other derived units include Power (work x time), Pressure (force per unit area), density (mass per unit volume).
1.1.2 : Definition of some fundamental units
Kilogram...a measure of mass, defined by a platinum-iridium cylinder kept in Sevres, France (Though I really can't imagine the IB asking that :)
Meter...unit of distance, defined as the distance traveled by light in sec, where the speed of light (about 3 x 108 m/sec).
Second...unit of time, based on time taken the number of vibrations in a cesium atom (9.1 x 10 ).
1.2 Vectors and scalars
1.2.1
Vector quantities have both a magnitude, and a direction. Scalar quantities have only a magnitude. Vector quantities are those such as displacement, velocity, acceleration. Scalar quantities are distance, speed, work and energy (those last two are important...apparently)
1.2.2
Vectors can be represented as lines, where the length is the magnitude and the direction is the direction on the paper. Vectors can be added by using a scale diagram...The first vector is drawn, then the second from the end of the first, and so on. The resultant vector goes from the beginning of the first to the end of the last...in that direction, not the other way.
1.2.3
Multiplying or dividing a vector by a scalar only affects the magnitude, not the direction...and works just like normal multiplication / dividing.
1.2.4
Place the vector as a diagonal of a rectangle...this allows the vertical and horizontal components to be calculated by pythag and basic trig. The sum of all the vertical components = the vertical component of the resultant vector and so for the horizontal.
1.3 Graphical techniques
1.3.1
Graphs should be drawn with the dependent variable on the vertical axis (unless the slop is supposed to be a particular unit over another, in which case use that). Usually only the dependent variable uncertainties are relevant, which means you only need vertical uncertainty bars ( and make sure you have a title, and label both axes...it's not like it requires any skill, and yet they still give marks for it :) Draw a line of best fit, usually a straight line, but not always...some points will probably have to be discarded, just to make things fun.
1.3.2
The units of the constant defining the slope of the graph will be . The range of possible slopes can be found by taking a maximum line of 'best' fit and a minimum line of 'best' fit using the uncertainty bars...Physics doesn't have to obey the foolish laws of grammar :)
The intercepts' relevance varies from graph to graph...in general, the intercept is the value of one component when the other is zero...ie on a temp vs pressure graph, the intercept will be a -273 c...representing absolute zero.
1.3.3
By playing around with powers (including negative powers) you can get a linear graph, from which it is much simple to determine the relationship. When you have a straight line which goes through the origin, the unit on the vertical axis is directly proportional to that on the horizontal axis.
1.3.4
Any straight line graph can be put in the form , where the slope and the intercept. Nb...If is not zero, then they are not directly proportional.
1.3.5
sin, or other repeating graphs have the following characteristics...amplitude -- the difference between the highest and lowest y values...Wavelength is the distance from the top of the crest of a wave to the top of the next crest (or equivalently, the distance between successive identical parts of a wave.) Period is the time required to complete one cycle ex. time for a pendulum to make one back and forth swing... frequency -- usually relevant in graphs against time, where frequency is the number of cycles per second...
1.3.6
Draw bar graphs...choose the appropriate intervals (they should all be of the same width, not too large or small to mask trends) and then find trends...Millikan's oil drop...the bars all differ by the same amount (the charge of an electron)...the frequency of values may increase or decrease with larger, or smaller values.
1.4 Uncertainties and errors
1.4.1
Uncertainties are due to lack of precision in measuring equipment, errors are actual inaccuracies ie equipment being mis-used, or mis-measurements...Uncertainties could come from the fact that a rule is only marked down to 1 mm, Errors could come if you miss read 15 on the ruler as 14...Uncertainties cause uncertainty bard, errors usually result in the particular piece of data being discarded.
1.4.2
Random uncertainties result from the magical randomness of measuring equipment...sometimes the jaws of a micrometer will close one way, sometimes another...they're random, and you can't do anything about them. Systematic errors are those built into the equipment.
1.4.3
Record uncertainty along with data. The minimum uncertainty is half the limit of the reading...ie if the measurement is 3.6g, then the uncertainty is ± 0.05g.
1.4.4
Random uncertainties are found by measuring the greatest difference from the arithmetic mean of the values...this decreases, at first rapidly and then more slowly as more data is collected. By using graphs we can obtain a line of best fit which wits within all the uncertainties.
1.4.5
When adding or subtracting, the uncertainty is the sum of the absolute uncertainties for each term. When multiplying or dividing, the uncertainty is the sum of the relative uncertainties (ie )...this can result in large uncertainties being created by performing operations on data with small uncertainties.
1.1 Standards of measurement
1.1.1 : Fundamental and derived units
Fundamental units are, in general those which can't be expressed in terms of others (there are exceptions). Mass, length, time, electric current (this is defined in terms of force between wires, but is fundamental in terms of electric circuits). The newton is a derived unit, because it is defined as the force required to accelerate 1kg at 1 ms-2. Other derived units include Power (work x time), Pressure (force per unit area), density (mass per unit volume).
1.1.2 : Definition of some fundamental units
Kilogram...a measure of mass, defined by a platinum-iridium cylinder kept in Sevres, France (Though I really can't imagine the IB asking that :)
Meter...unit of distance, defined as the distance traveled by light in sec, where the speed of light (about 3 x 108 m/sec).
Second...unit of time, based on time taken the number of vibrations in a cesium atom (9.1 x 10 ).
1.2 Vectors and scalars
1.2.1
Vector quantities have both a magnitude, and a direction. Scalar quantities have only a magnitude. Vector quantities are those such as displacement, velocity, acceleration. Scalar quantities are distance, speed, work and energy (those last two are important...apparently)
1.2.2
Vectors can be represented as lines, where the length is the magnitude and the direction is the direction on the paper. Vectors can be added by using a scale diagram...The first vector is drawn, then the second from the end of the first, and so on. The resultant vector goes from the beginning of the first to the end of the last...in that direction, not the other way.
1.2.3
Multiplying or dividing a vector by a scalar only affects the magnitude, not the direction...and works just like normal multiplication / dividing.
1.2.4
Place the vector as a diagonal of a rectangle...this allows the vertical and horizontal components to be calculated by pythag and basic trig. The sum of all the vertical components = the vertical component of the resultant vector and so for the horizontal.
1.3 Graphical techniques
1.3.1
Graphs should be drawn with the dependent variable on the vertical axis (unless the slop is supposed to be a particular unit over another, in which case use that). Usually only the dependent variable uncertainties are relevant, which means you only need vertical uncertainty bars ( and make sure you have a title, and label both axes...it's not like it requires any skill, and yet they still give marks for it :) Draw a line of best fit, usually a straight line, but not always...some points will probably have to be discarded, just to make things fun.
1.3.2
The units of the constant defining the slope of the graph will be . The range of possible slopes can be found by taking a maximum line of 'best' fit and a minimum line of 'best' fit using the uncertainty bars...Physics doesn't have to obey the foolish laws of grammar :)
The intercepts' relevance varies from graph to graph...in general, the intercept is the value of one component when the other is zero...ie on a temp vs pressure graph, the intercept will be a -273 c...representing absolute zero.
1.3.3
By playing around with powers (including negative powers) you can get a linear graph, from which it is much simple to determine the relationship. When you have a straight line which goes through the origin, the unit on the vertical axis is directly proportional to that on the horizontal axis.
1.3.4
Any straight line graph can be put in the form , where the slope and the intercept. Nb...If is not zero, then they are not directly proportional.
1.3.5
sin, or other repeating graphs have the following characteristics...amplitude -- the difference between the highest and lowest y values...Wavelength is the distance from the top of the crest of a wave to the top of the next crest (or equivalently, the distance between successive identical parts of a wave.) Period is the time required to complete one cycle ex. time for a pendulum to make one back and forth swing... frequency -- usually relevant in graphs against time, where frequency is the number of cycles per second...
1.3.6
Draw bar graphs...choose the appropriate intervals (they should all be of the same width, not too large or small to mask trends) and then find trends...Millikan's oil drop...the bars all differ by the same amount (the charge of an electron)...the frequency of values may increase or decrease with larger, or smaller values.
1.4 Uncertainties and errors
1.4.1
Uncertainties are due to lack of precision in measuring equipment, errors are actual inaccuracies ie equipment being mis-used, or mis-measurements...Uncertainties could come from the fact that a rule is only marked down to 1 mm, Errors could come if you miss read 15 on the ruler as 14...Uncertainties cause uncertainty bard, errors usually result in the particular piece of data being discarded.
1.4.2
Random uncertainties result from the magical randomness of measuring equipment...sometimes the jaws of a micrometer will close one way, sometimes another...they're random, and you can't do anything about them. Systematic errors are those built into the equipment.
1.4.3
Record uncertainty along with data. The minimum uncertainty is half the limit of the reading...ie if the measurement is 3.6g, then the uncertainty is ± 0.05g.
1.4.4
Random uncertainties are found by measuring the greatest difference from the arithmetic mean of the values...this decreases, at first rapidly and then more slowly as more data is collected. By using graphs we can obtain a line of best fit which wits within all the uncertainties.
1.4.5
When adding or subtracting, the uncertainty is the sum of the absolute uncertainties for each term. When multiplying or dividing, the uncertainty is the sum of the relative uncertainties (ie )...this can result in large uncertainties being created by performing operations on data with small uncertainties.
Program
پنجشنبه هفتم آبان : اندازه گیری - ؛جایزه نوبل 2009
یکشنبه دهم آبان: بدفهمی در فیزیک؛ مکانیک - نور
First Step
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