Demonstrations in Class for Physics 150, Fall 2003
1. Lecture 1: Introduction
• Purpose: To illustrate mechanics of a few bodies
• Observe motion that is surprising yet simple
2. A deck of cards
• Purpose: To illustrate order and entropy
• Throw cards in the air - entropy (disorder) of universe increases
• Put cards back in order - Does entropy of universe increase?
3. Tesla Coil with Light Bulb
• Purpose: To illustrate electromagnetic energy and waves, light, and quantum mechanics
• Coil induces sparks in second coil; sparks to wire held by instructor (student)
• Causes fluorescent tube, neon gas to glow; Lines seen in grating show effect of quantum mechanics
4. Atomic Spectral Lines and Diffraction Gratings
• Purpose: To illustrate quantum mechanics
• Observe definite lines from a given element
5. Geiger Counter
• Purpose: To illustrate uncertainty principle quantum mechanics
• We cannot predict which nucleus will decay next. Does "God throw dice"?
2. Lecture 2:
1. Bow and arrow
• Purpose: Visualize Aristotle's theory of motion
2. Toy cars with small and large friction
• Purpose: Low and High friction motion
3. Steel Balls of different weight
• Purpose: Low friction motion
4. Steel plate onto which to drop the balls
• Purpose: falling of bodies with different weight
5. Balls dropping in water, glycerin
• Purpose: Falling in media with different viscosity (friction)
• Compare approaches of Aristotle and Galileo
6. Bowling ball rolling on incline with flashing lights
• Purpose: To illustrate how Galileo "slowed down" effects of gravity to make them easier to measure
• Purpose: Shows that mathematics can be used to transform equation to a different form that can be more readily tested.
• Lights flash at equal intervals, spaced at distances of 1, 4, 9, 25, 36, ... units
7. Constant acceleration using demos from Web site "Java Applets on Physics"
3. Lecture 3: Toward Science of Mechanics
1. Penny and Feather dropping in air and vacuum
• Purpose: Nowadays we can realize the frictionless case
2. Electric tractor on a large sheet of cardboard
• Purpose: Demonstrate relative motion in a line and in two dimensions
3. Two Ball Drop
• Purpose: Show the balls hit the ground at the same time - Independence of X-Y motion
4. Shoot the Monkey
• Purpose: Show dart and monkey fall with the same acceleration since each is falling freely
5. Projectile motion using demos from Web site "Java Applets on Physics"
4. Lecture 4: Astronomy: The problem of the planets
1. Sun, Earth, and Moon Rotations
• Purpose: Show the sun and moon relative to the earth; phases of the moon
2. Shadows on Earth by Sun - I
• Purpose: Show how circumference of earth was measured more than 300 years BC
Have globe with two vertical sticks at different lattitudes; floodlight that can be held by hand
3. Shadows on Earth by Sun - II
• Purpose: Show how distance to moon and sun were measured more than 300 years BC
using globe small ball (baseball, ping pong ball) and floodlight
4. Model of Solar System
• Purpose: Show Phases of Venus; earth orbit; etc.
5. Kepler's laws illustrated with demos from Web site "Java Applets on Physics"
5. Lecture 5: Newton's 3 Laws and the Universal Law of Gravitation
1. Tractor on a card
• Purpose: To show motion in more than one dimension (same idea as in previous lecture)
2. Vectors: Circular chalkboard and magnetic stick-on vectors Also using demos from Web site "Java Applets on Physics"
• Purpose: To show vector addition and acceleration in circular motion
3. Cannon on a cart
• Purpose: To show how motion is relative: Galilean invariance. (Related to 1st law.)
4. Cannon on a cart with pulley (same equipment as above)
• Purpose: To show acceleration caused by a force (2nd law)
5. Rocket Cart (Fire Extinguisher cart)
• Purpose: To show action/reaction principle (3rd law)
6. Ball on a string
• Purpose: To show circular motion, force due to string
6. Lecture 6: Conservation Laws
1. Air track with carts
• Purpose: To show conservation of momentum (3rd law, but even more general)
2. Bowling ball on wire from ceiling
• Purpose: To show conservation of energy (Professor bravely lets it swing right up to his nose
3. Track with rolling ball (NOT actually used in 2003)
• Purpose: To show conservation of energy as ball rolls
4. Bow and arrow
• Purpose: To illustrate transformation of energy between different forms
5. Ball to drop
• Purpose: To illustrate transformation of energy between gravitational, kinetic, heat
7. Lecture 7: Second Law of Thermodynamics
1. Dye dropped into water
• Purpose: To show dissipation of dye as example of decrease of order - evolution to morev probable states
2. Steam engine
• Purpose: To show a heat engine that takes in hot staem and exhausts cooler steam or water
3. Liquid Nitrogen steam engine
• Purpose: To show that steam engine camn work between any two tempartures
8. Lecture 8: Electric and Magnetic Forces
1. Pith Balls and Rod
• Purpose: 1. To illustrate Electric Forces; 2. to show there are two types of electric charge; 3. to make the point that there is a question how fast the force travels.
2. Electroscope
• Purpose: To illustrate Electric Forces and to show there are two types of electric charge.
3. Wimhurst Machine (Turning wheel with wire brushes that generates large voltages)
• Purpose: To illustrate effects of large electric fields
4. Bar magnets on Vu Graph Projector
• Purpose: To illustrate Magnetic Forces.
5. Battery causing electric current
• Purpose: Conversion of chemical energy to electrical energy
6. Wire carrying current and compasses on Vu Graph Projector
• Purpose: Electric current causes Magnetic Forces
9. Lecture 9: Review of classical physics through Newton and second law
10. The demos below are good review but were not actually done.
1. Globe + Floodlight
• Purpose: Reminder of how ancient Greeks measured the radius of the earth, and distance to sun and moon
2. Various cylinders rolling down inclined plane
• Purpose: Answer question posed in class. Is it true what Galileo said, that rolling on an inclined plane is just like free fall but slowed down?
3. Vectors on circular chalk board
• Purpose: Reminder of circular motion
4. Ball on a string
• Purpose: Reminder of circular motion
11. Lecture 10: Maxwell: Electromagnetic Waves
1. Pith Balls and Rod
• Purpose: To make the point that there is a question how fast the force travels
2. Tesla Coil and tubes with neon gas; fluorescent tubes
• Purpose: To illustrate that electric sparks generate effects at a distance
3. Electromagnetic Cannon (Sudden pulse of current generates large magnetic field that shoots off conducting ring)
4. Electromagnetic Cannon Lights a Light Bulb
• Purpose: Both demos illustrate that a pulsed (changing) electric field generates magnetic field and changing magnetic field generates electric fields
12. Lecture 11: Waves and Interference
1. Prism and white light source
• Purpose: To illustrate the questions about light in Newton's time. Newton believed light was particles that were separated by the prism.
2. Bright light for showing diffraction effects - student can hold up small object or make narrow gaps with their finger to see diffraction patterns
• Purpose: To illustrate that light acts like a wave
3. Slinky spring stretched on the floor
• Purpose: To illustrate waves: transverse, longitudinal
4. Standing wave machine with Strobe
• Purpose: To illustrate wave motion
5. Music instrument
• Purpose: To illustrate that waves on a string of fixed length have only fixed wavelengths and frequencies
6. Interference of Sound from two speakers
• Purpose: To illustrate interference of sound from two sources that are in phase. Students can move side to side and hear interference.
7. Interference of light from laser and two slits
• Purpose: To illustrate that light shows the same type of interference as sound. Light is a wave. This is where things stood in 1880 after Maxwell.
13. Lecture 12: Summary of Classical Physics; Michelson-Morley Exp.; Does the Earth really move?
1. Tractor on card
• Purpose: To illustrate motion of a swimmer upstream, downstream, and across the stream
2. Sodium Lamp and glass plates
• Purpose: To illustrate interference of light
• Observe changes in the interference pattern
3. Michelson Interferometer with laser and cell in which air pressure can be pumped by small hand pump
• Purpose: To illustrate Michelson-Morley Exp. and the interference of light in the two arms
• Very small changes of pressure in the cell in one arm change the speed of light and change the interference pattern
14. Lecture 13: Special Theory of Relativity: Einstein
• No demos: "Gedanken Experiments"
15. Lecture 14: The Wedding of Space and Time
1. "Smith's Relativity" Created by Dr. J. Smith, transparency on overhead projector that demonstrates the light-and-clocks basis for special relativity.
• Purpose: To show the there must be time dilation if the speed of light is the same to all observers
• Shows light crossing a train perpendicular to the motion, as seen by obervers on train and on te ground.
• Note: the length perpendicular to the motion does not change - as can be seen by the fact that the train still fits on the track! (It is NOT obvious this must still be true at high speed - but it is obvious once one sees that both observers must observe the same physical phenomena, i.e., that the train moves on the track. Also the effect must be symmetrical: if the apparrent length in this dierction changed they could not agree on the facts.)
16. Lecture 15: The faster you go the heavier you get: E = mc2
• No demos: "Gedanken Experiments"
17. Lecture 16: General Relativity: gravity and acceleration
• No demos: "Gedanken Experiments"
18. Lecture 17: Continue General Relativity
1. Earth Globe
• Purpose: To show the idea of curved space-time for a person restricted to the surface. Shortest lines is geodesic, not a straight line. "Parallel" lines meet. Lines return to themselves. Sum of angles ofany triangle greater than 180 degrees.
19. Lecture 18: Review before Exam 2: Reminder demos
1. Tesla Coil and tubes with neon gas; fluorescent tubes
2. Interference of Sound from two speakers
3. Music instrument.- standing sound wave
4. Michelson Interferometer with laser and cell in which air pressure can be pumped by small hand pump
5. "Smith's Relativity" Created by Dr. J. Smith, transparency on overhead projector that demonstrates the light-and-clocks basis for special relativity.
6. Globe
• Demos for lectures to be added during the course