Introduction to Circuits

Objectives and Overview

In this lesson, you’ll explore basic circuits and conductive materials. You’ll use Makey Makey, an invention kit for creating interactive projects by experimenting with a variety of conductive objects that you may not otherwise have considered.

Lesson Objectives

• Be able to identify a basic circuit
• Describe the circuit connection of an LED and coin cell battery
• Identify conductive materials
• Be able to recognize and explain a simple circuit drawing

What is a Circuit?

A circuit is a closed path through which electricity flows. If there is a break in the circuit, the current will cease to move. You’ll see through these projects that a switch works by opening and closing a circuit.

Take a look at an LED. The long leg is called the anode, or positive lead. The shorter leg is the cathode or negative lead.

Now, take a look at this circuit sketch. This is a drawing of a coin cell battery connected to an LED. What this shows is a connection between the positive side of the battery and the positive side of the LED and another connection between the negative side of the battery and the negative side of the LED.

Conductive Materials

Materials such as copper are conductive, which means that electricity can flow through. Materials like rubber are insulating, which means that electricity can’t move as easily through.

Some objects that you may not have considered as conductive are fruits and vegetables. While fruits and vegetables don’t produce electricity themselves, they contain liquids that are conductive, such as electrolytes.

There are many online resources for conductive materials. Here are some examples:

• Fruits and vegetables- experiment to see which work!
• Copper and other metals.
• Some plants (as long as they aren’t dried out)
• Play-Doh and other modeling clays (as long as they aren’t dried out)
• Graphite from a pencil, but you’ll need to experiment with the thickness
• Aluminum foil
• People!

This is not a complete list of conductive objects. If some of these objects surprise you, conduct some research to discover what makes certain things more conductive than others. One of the strengths of the Makey Makey is that through exploring and discovering conductive materials, you’ll be able to more fully take advantage of the interactive nature of the kit because you’ll not be limited to just using foil and other metals.