Smoke rings offer wonderful lessons in fluid dynamics. Use them to initiate discussions on fluid flow, air pressure, and Bernoulli's principle. This lesson contains instructions for how to build your own smoke ring machine out of an empty soda bottle, and outlines the physics...

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

This experiment demonstrates the basic features of hurricanes and tornadoes in spectacular fashion. With a kitchen turntable or a spinning stool, it can be put together with common classroom materials. A tutorial on hurricanes is included. Lecture slides are attached.

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Instructions for building the vortex in a bottle, a device that produces a vortex like the one found in a bathtub drain. The device is completely self-contained and can be used in any classroom setting. It is simple enough and cheap enough for students to build their own to t...

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.

This lesson outlines the construction and operation of a pendulum wave machine that can be built from inexpensive materials in the classroom. Building the demonstration requires a fair amount of patience: construction only takes about 30 minutes, but adjustments and fine tuni...

This lesson describes how to construct a simple and inexpensive micrometer that can be used to measure objects up to several centimeters thick. It has a readout accuracy of 0.1mm or better, with a potential precision of 0.01mm. Construction time is about 30 to 60 minutes plus...

Bernoulli's principle states that a region of fast moving fluid exerts less pressure on its surroundings than a region of slow moving fluid. This principle explains a clever trick for blowing up a long thin balloon in a single breath. Stage a friendly competition in class and...

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.

Altho...

The Bernoulli principle states that a region of fast flowing fluid exerts lower pressure on its surroundings than a region of slow flowing fluid. The principle applies to the motion of air over an airplane wing, to air flow through a carburetor, to a flag flapping in the bree...

Superabsorbent polymers (SAP's) are used to absorb and retain liquid in a variety of applications, including baby diapers and potting soil. One common SAP, known commercially as "instant snow", is sold as a white powder that can absorb several hundred times its weight in wate...

Turn a glass of water upside down without letting the water fall out. The secret to this trick involves some basic lessons in air pressure. Best performed over a teacher's head.

This lesson gives some information on Earth's magnetic field: the physics of how it is produced and its geologic history. Many suggestions for further reading are also listed. It might be considered useful background for any activity having to do with magnetic compasses. Lect...

The Lilac Chaser illusion is a creation by Jeremy Hinton that relates to the effects of desensitization (and afterimages), motion-induced blindness, and beta movement (perceiving motion from static images). It makes a great follow-up activity after a lesson on negative afteri...

A lesson on zeotropes, phenakistoscopes and other vintage animation technologies, with explanations and attached printouts for making your own version.

This lesson provides an overview of the anatomy of the eye and suggests several simple activites for exploration, including

• observing pupil response to variations in light
• verifying the inverted image on the retina
• comparing central and peripheral v...

This lesson provides a tutorial in color perception and the physiology of color sensitive cells in the eye. It includes three classroom activites for exploring color vision:

1. a game testing peripheral color vision
2. a demonstration of mixing colored light usin...

Cheshire cat illusions are images that fade slowly away as you stare at them. They result from desensitization in the eye (and brain) when you view them without moving your eyes. This lesson explains the mechanism behind the disappearance, and provides several examples of opt...

Construction plans and suggestions for a homemade telegraph. Serves as a good application for studying electromagnets.

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, che...

Diamagnetic materials are repelled by a magnet, in contrast to magnetic materials (like iron), which are attracted to a magnet. This lesson describes several demonstrations of diamagnetic repulsion using water and graphite (both diamagnets), with inexpensive setups. The most...

This lesson provides

• plans for making a simple compass and
• tips on magnetizing a needle

learning goals:

• understand the mechanism behind magnetization
• figure out which way is north

For other ideas and more in-depth...

This lesson gives instructions for one of the simplest and most popular designs for a homemade motor. It can be used as an in-class demonstration, or a hands-on activity for students, or a take-home kit. In any of these modes, it offers a wonderful introduction to the working...

This lesson provides some general background on electromagnets and describes three simple activities for students to explore on their own. For reference, it also includes formulas for the magnetic field strength around several common types of electromagnets.

learning go...

This lesson describes a simple motor that can be constructed in 15 minutes with inexpensive materials. It involves all the basic principles of motors involving magnetic force, electromagnets, and commutators (rotating switches common in many commercial motors). This device is...