Complex Circuits

Activity 4

Purpose

Students will practice algorithmic thinking by engaging in tasks that have them think about conditions that lead to specified outcomes. In the identity activity, this is accomplished by having students discuss how identities can shape how people make decisions. In the circuit activity, this is considering how multiple inputs to a circuit can affect the output of the circuit (lighting an LED).

Materials

For each participant:

1 battery 9 V
1 resistor (220 Ohm)
1 LED
5 wires
1 pushbutton
1 potentiometer
1 breadboard

Vocabulary

pushbutton
potentiometer
breadboard
LED
battery
breadboard
potentiometer

Identity Activity

Intersectionality & Power

This activity engages students in thinking about how power and identities interact with one another. By working in groups, students should discuss their responses to a series of statements about people based on their "identity cards". These statements are yes or no questions based on whether they think someone would be able to perform that action given their intersectional identities.

Directions

Have the students get into groups of 2-3
Explain the activity
Put up the sample statements, or hand them out with each identity card
Hand out the identity cards, with each group getting one identity card to discuss (4 groups for 4 identity cards)
For a few minutes (recommended: 5) have the students think about what their responses to the combination of identity and statements are.
Once they've had time to think about it by themselves, have them discuss within their groups their responses. Have them come to a consensus, or figure out where they do not agree. (recommended: 15-20 min)
As a large group, have each small group share out the identity and the response they had. Some questions to prompt the discussion:
- Who answered all yes? All no? Why?
- Where were some points that the group disagreed? Why?
- How did their identities interact with one another, if at all? Was one identity more relevant than the others?

This activity is adapted from a presentation of this teaching note.

intersectionality_activity.pdf

Using a Potentiometer

A potentiometer similar to the one that will be used in this activity

A potentiometer is a type of resistor that can change the amount of resistance that it has. This is helpful for when you want to have more than two values for something, such as a dimming light or a radio station number. You can read more about how they work here!

Most important to note about the potentiometer for this lesson is that it has 3 prongs that are inserted in the breadboard instead of two (like the push button).

The leftmost and rightmost prongs will be used for the connection to positive or negative voltage, or ground (GND) depending on your needs for the circuit
The center prong will be used as our connection to the LED (where the signal is coming from)

Illustration of a simple circuit with a potentiometer

Using the Potentiometer in a Circuit

Similarly to the push button, we can use a potentiometer in a circuit to control an LED. Unlike a push button, we can change the brightness of the LED, rather than just turning it on and off.

To try this out, recreate the circuit pictured to the left! Here are a few pointers:

The blue power rail is being used as the negative side
The red power rail is being used as the positive side
The potentiometer in the image might look a bit differently than the one you have, but it works the same way!
Once the circuit is assembled, try turning the knob at the top of the potentiometer. If it is working, the light of the LED should be either getting brighter or dimmer, depending on the direction you turn it. If not, you might want to check the connections again to be sure the circuit is built correctly.

Once you've explored how the potentiometer works in this circuit, you can start making it more complex by adding a push button!

Creating a Complex circuit

Once you've figured out how to use the potentiometer in a simple circuit, you can make it more complex by adding more input components. In this example, we will combine the push button and the potentiometer.

If you want to refresh your understanding of using a push button in a circuit, you can check out lesson 3 of this unit!

Illustration of completed circuit

Questions to consider before starting

What do you think this circuit will do? Why do you think that?

Combining multiple inputs to an LED

To start, create a simple circuit with a potentiometer (seen above).
- When that circuit is done, the LED should change brightness as the value of the resistance on the pot changes.
Once you have created that circuit, add a push button between the rightmost prong of the potentiometer and the positive voltage (seen to the left).
Once your circuit is done, it should be connected similarly to the image on the left.

Questions to consider once finished

Now that you have built it, can you tell me what this circuit does?
Where else could we have put the push button to have the same effect? If you aren't sure, try connecting the push button in the same way to the leftmost prong of the potentiometer. Does it still work? Why do you think it does/does not?
What do you think would happen to the LED if the second static (not changing) resistor was removed from the circuit? Try it!

REflection

Where do you see examples of potentiometers in your life?
Do you think that the activities from today allowed to to work with other students? Why or why not?
Could you explain how a potentiometer works to someone else? How would you describe it?

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