Amazing Lasers! - Cheapy Lighter Laser Burner! SCIENCE HOBBYIST: Top Page. The Most Useless Machine. How to Recover a Master Lock Combination | TVLesson. Chapter 2: Electromagnetism -- Build a railgun in 10 minutes. A railgun is a device for accelerating an object by running electric current through it along a pair of rails. When large amounts of power are used, the railgun becomes a potent weapon. But the principles can be demonstrated safely by using a smaller amount of power, in our case, from a 9 volt battery. When a small amount of power is used, the rails can be re-used many times. If larger amounts of power are used, the railgun becomes a one-shot device, as the rails are destroyed in the process of shooting the gun, due to arcing and flexing of the rails. There are several types of rail gun, each with a different method of accelerating the object.
This version is called a linear homopolar motor. Click on image for an animated picture What you need A piece of cardboard or wood for a base. Click on image for a larger picture We start by spreading a thin layer of glue on the base, to hold down the foil strips. Next we attach the battery with the clip leads. Firing the railgun How does it do that? Lesson Plan for Making a Speaker Laboratory. ©1995 The Regents of the University of California by Regan Lum Introduction: A speaker is a device that converts an electronic signal into sound. The speaker you will build (see figure 1) consists of a Styrofoam or paper cup, a coil of wire, a permanent magnet, and a signal source.
Figure 1 Purpose: In this laboratory, you will explore how a speaker works. Materials: 1 permanent magnet 2 feet of wire 1 pencil tape or glue 1 Styrofoam or paper cup 1 signal source (tape player) 1 plug with alligator clips for tape player Procedure: Assemble material as shown in figure 1. Leaving about 10 centimeters on the end, wrap the wire around a pencil to make a wire coil and tape or glue it to the bottom of the cup. Conclusion Does the volume control on the tape player work on your speaker? Return to CEA Science Education Home Page.