An electrical circuit is like a NASCAR raceway.  The electrons (racecars) zip around the race loop (wire circuit) superfast to make stuff happen. Although you can’t see the electrons zipping around the circuit, you can see the effects: lighting up LEDs, sounding buzzers, clicking relays, etc.

There are many different electrical components that make the electrons react in different ways, such as resistors (limit current), capacitors (collect a charge), transistors (gate for electrons), relays (electricity itself activates a switch), diodes (one-way street for electrons), solenoids (electrical magnet), switches (stoplight for electrons), and more.  We’re going to use a combination diode-light-bulb (LED), buzzers, and motors in our circuits right now.

A CIRCUIT looks like a CIRCLE.  When you connect the batteries to the LED with wire and make a circle, the LED lights up.  If you break open the circle, electricity (current) doesn’t flow and the LED turns dark.

LED stands for “Light Emitting Diode”.  Diodes are one-way streets for electricity – they allow electrons to flow one way but not the other.

Remember when you scuffed along the carpet?  You gathered up an electric charge in your body.  That charge was static until you zapped someone else.  The movement of electric charge is called electric current, and is measured in amperes (A). When electric current passes through a material, it does it by electrical conduction. There are different kinds of conduction, such as metallic conduction, where electrons flow through a conductor (like metal) and electrolysis, where charged atoms (called ions) flow through liquids.

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Here’s what you need:

• 2 AA batteries
• AA battery case
• 2 alligator wires
• LEDs (any you choose is fine)

Download Student Worksheet & Exercises

Be alert for:

1. Batteries inserted into the case the wrong way!

2. LED in the wrong way (LEDs are picky about plus and minus – they are POLARIZED)

3. Is there a metal-to-metal connection?  (You’re not grabbing ahold of the plastic insulation, are you?)

4. Bad wires can cause headaches – if all else fails, then swap out your alligator clip lead wires for new ones.

Exercises

1. What does LED stand for?
2. Does it matter which way you wire an LED in a circuit?
3. Does the longer wire on the LED connect to plus (red) or minus (black)?
4. Do you need to hook up batteries to make a neon bulb light up?  Why or why not?
5. What’s the difference between a light bulb and your LED?
6. What is the difference between a bolt of lightning and the electricity in your circuit?
7. What is the charge of an electron?

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