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displaying 31 - 40 of 52 lessons
title description rating updated author
Balancing Magnetic Coins

This lesson describes a magic trick with magnetic coins (or washers) that demonstrates some important principles in magnetism. It's a good lead-in to a conversation on magnetic materials and magnetization.

For other ideas and more in-depth explorations of magnetism,...

Average: 4.4 (9 votes)
22-May-2015 guy
Getting to Mars the Easy Way

Two different methods of getting to Mars are proposed. A simple analysis shows that one is better than the other. The reasons for the difference are explored, yielding an insight into orbital mechanics. The topic is appropriate for any high school physics class familiar with...

Average: 4.5 (2 votes)
5-Apr-2015 gsgreenstein Mars from Hubble

This lesson describes how to construct a simple siphon and gives a general tutorial on how siphons work. Lecture slides with extra figures are attached.

Average: 3.3 (10 votes)
28-Oct-2014 guy siphon with pressure
Phone Book Friction

It is possible to shuffle two phone books together in a way that they will withstand thousands of pounds of force to pull them apart. This lesson shows an example with discussion of the general principles.

Average: 3.6 (12 votes)
23-Jun-2014 guy
Benham's Top

In 1894, Charles Benham invented a top with a black and white pattern that produces a sense of color when it spins. This lesson contains instructions and materials for producing your own Benham top, as well as a short explanation behind the false color perception.


Average: 4 (5 votes)
14-Jun-2014 guy
Balancing Forks - A Study in Center of Mass

Two forks and a pair of toothpicks are all you need to perform an amazing balancing act (figure 7). Use this demonstration to teach students the fundamentals about "center of mass". A basic tutorial on center of mass concepts is included. Lecture slides are attached.

Average: 4.5 (10 votes)
12-Jun-2014 guy forks and salt shaker
Flip Books

A lesson on flip books, with an attached book to print out and pointers on how to make your own flip book.

Average: 4.5 (2 votes)
2-Jun-2014 guy sciphile detonated
Shades of Inhibition - Optical Illusions with Lateral Inhibition

Look carefully at the optical illusion in figure 7. The green cylinder appears to cast a shadow across the checkerboard. However, the shades of the squares are not what they appear to be. Photoreceptors in the human retina are wired to the brain in such a way as to emphasize...

Average: 3.8 (4 votes)
2-Jun-2014 guy checker shadow illusion
A Survey of Homemade Batteries

A general overview of battery chemistry and operation, with examples of several types of homemade batteries. Tables of suggested materials and sources are included.

Average: 4.3 (35 votes)
2-May-2014 guy Coke can battery
Slow Motion Magnets

Drop a strong magnet through a copper pipe and watch it slow down as it enters the pipe. The invisible drag is caused by forces between the pipe and the magnet, induced according the laws of electromagentism. It's a magical demonstration for a class, made even better if the...

Average: 4 (7 votes)
24-Apr-2014 guy slow motion magnet