Simple Circuit

In this lesson, students practice decomposing problems by creating puzzles that they can take apart and the individual components that complete a simple circuit. In addition, students practice abstraction by identifying the similarities and differences between multiple types of circuits.

All of these components can be put together to create a circuit. A circuit is “the path that charged particles take as they move from one side of a power source to another”.

Battery: Circuits start with a power source. The power source for us today is a 9V battery.

Current: The amount of electrons flowing in a circuit during a period of time. The rate of the flow is measured in amperes, known as Amps.

Voltage: You can’t have a current without an energy source pushing the electrons. Voltage is the amount of potential energy (or electrical pressure) in a source like a battery. Voltage is like water pressure: the higher the voltage, the more it can push electrons through a circuit.

LED: A Light Emitting Diode (LED) is a diode that emits light when a current flows through it. An LED has two terminals (or legs). The longer end is the positive end (+) and the shorter end is the negative end (-).

Conductive material: A conductive material is any material that allows electricity to flow from one point of the circuit to another point. Common conductive materials are wires made out of copper and copper tape. For example, when you want to light a lamp, you need a wire or a conductive material to run the current from the power source, usually a wall outlet, to the light bulb.

Circuit: All of these smaller component parts can be put together to create a circuit. A circuit is the path that charged particles take as they move from one side of a power source to another.

Q: Can you think of an example of where you might see a circuit in your house?

Directions:

1. Attach the battery snap to the top of the 9V battery.
2. Attach the black wire (negative) to the negative end of the LED (short leg, aka cathode). To make sure the wire stays attached, bend and wrap the cathode around the metal end of the wire.
3. Attach the red wire (positive) to one end of a resistor. To make sure the wire stays attached, bend and wrap the metal end of the resistor to the metal end of the wire.
   • Unlike with the LED, it doesn't matter which end of the resistor you attach this wire to. Electricity will flow the same way through a resistor regardless of the direction the resistor color bands are pointing. This means we don't have to worry about how we attach the resistor in the circuit.
4. Take another wire and attach it to the other end of the resistor. Make sure to wrap the metal part of the resistor around the metal part of the wire to keep it attached
5. Touch the metal end of the wire to the positive leg (longer, aka anode) of the LED. While the wire is touching the LED will light up. This is because it is a complete circuit. If you disconnect the wire from the LED, the LED will not light up because the circuit is broken

Once complete, it should look something like the images below.

Now, see if you can abstract this knowledge to other types of circuits, some of which you may have seen before! The following images are all different types of circuits; see if you can name all the parts that are going into the circuit. What parts are the same? What parts are different? What is missing? What components do you not understand?

• Did you work together with others to create your circuit? why or why not?
• What are some examples of simple circuits you see in real life?
• How would you explain a circuit to someone else?