Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes.

Question

Vocabulary: circuit, closed circuit, conductor, current, electron, fuse, insulator, open circuit, parallel circuit, series circuit, short circuit

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1.	What do a light bulb, a toaster, a radio, and a computer all have in common?

2.	Suppose you connect a battery to a small light bulb with a single wire. What do you think will happen? Explain your answer.

Gizmo Warm-up: Build a circuit

1.	Using the Standard components in the upper left of the Gizmo, try to get a light bulb to light up. You can drag as many bulbs, wires, batteries, switches and fuses as you like onto the circuit board.

A circuit is a path containing easily moveable charges. When the light bulb lights up, negatively-charged particles called electrons are flowing through the wire and bulb. This flow is called current.

2.	Now try to light the bulb with the smallest number of components.

3.	Based on what you have seen, what must be true for a circuit to light a bulb?

Activity A:

Closing a circuit	Get the Gizmo ready: 
●	Click Clear.
●	Turn on Show current and select Electron flow.
●	Set up components as shown to the right.

Introduction: You should have just built an open circuit (shown above). The gap on the left prevents the flow of charges. There are no gaps in a closed circuit, so charges can flow.

Question: What materials will close a circuit?
1.	Predict: Conductors are materials with easily movable charges, allowing current to occur. Insulators do not have easily movable charges, so current is not produced. Look at the nine Materials at lower left.

Which do you think are conductions?	
Which are insulators?

A.	Predicted conductors:	
B.	Predicted insulators:

C.	How could you use your open circuit to test if a material is a conductor or insulator?

2.	Experiment: Drag each material into the gap of the open circuit. If the light bulb lights, the material is a conductor. If not, the material is an insulator. Keep track of your findings below.

Conductors	Insulators

3.	Analyze: Look at your list of conductors.

A.	What kind of material are most conductors?

B.	Did any conductor have a different effect on the light bulb than the others? Explain.

Activity B:

Series circuits	Get the Gizmo ready: 
●	Click Clear.
●	Check that Show current is on.
●	Build the circuit shown to the right.

Question: In a series circuit, components are arranged in a single loop. What are the characteristics of series circuits?

1.	Observe: Turn the switch to ON, which allows charges to flow through the circuit. Notice how brightly the bulb is lit and how much current (shown by the arrows) there is. Now start replacing wire segments with light bulbs. You can fit up to four bulbs in this series circuit.

A.	What do you notice about the brightness of the bulbs as you add more bulbs?

B.	Do all the bulbs have the same brightness?

C.	Look at the current arrows in each part of the circuit. Are there any parts of the circuit that have more current than other parts?

2.	Explore: Now remove a light bulb from your series circuit, leaving a gap. What happens to the remaining bulbs?

3.	Extend your thinking: Build another series circuit with several light bulbs, a 1.5-volt AA battery, and at least a few wire segments. Turn the switch to ON.

A.	How does a circuit with a 1.5-volt battery compare to a circuit with a 9-volt battery?

B.	Replace one of the wire segments with another 1.5-volt battery. What happens?

4.	Compare: Compare a series circuit powered by six 1.5-volt batteries to a series circuit powered by a single 9-volt battery. Make sure there are equal numbers of light bulbs in each circuit and that the batteries are all in the same orientation.
What do you notice?	
Why is this true?

Activity C:

Parallel circuits	Get the Gizmo ready: 
●	Click Clear.
●	Check that Show current is on.
●	Build the circuit shown to the right.

Question: In a parallel circuit, there is more than one path that current can take. What are the characteristics of parallel circuits?

1.	Observe: Turn the switch to ON, which allows charges to flow through the circuit. Notice how brightly each bulb is lit and how much charge is flowing in each part of the wire. Are the two bulbs equally bright?

2.	Experiment: Add two more light bulbs to the circuit, as shown to the right. Turn the switch to ON, and observe the brightness of the bulbs.

A.	Did the brightness of the bulbs change?	
B.	Remove one light bulb. What happens?

C.	How did the parallel circuit respond differently to these changes than a series circuit?

Adding bulbs:	
Removing bulbs:

3.	Observe: Replace one of the light bulbs in your circuit with a wire. Now there is a path in the circuit with no light bulb to slow down the moving charges. What happens?

This situation is called a short circuit. The red arrows indicate enormous current. This is very dangerous          because so much current will heat up the wire and could even start a fire!

4.	Apply: Short circuits can be avoided using fuses, devices that melt if too hot. Set up the circuit shown to the right, and turn the switch ON.

A.	What happens?	
B.	Create a short circuit. What happens now?	
C.	How does a fuse make the circuit safer?

GPT-4o mini · Answer

## Prior Knowledge Questions 1. **What do a light bulb, a toaster, a radio, and a computer all have in common?** - They all require an electric current to function; they are all electrical devices that convert electrical energy into other forms of energy, such as light, heat, sound, or data processing. 2. **Suppose you connect a battery to a small light bulb with a single wire. What do you think will happen? Explain your answer.** - If you connect a battery to a small light bulb with a single wire, the light bulb will not light up because there is no complete circuit. A complete or closed circuit is necessary for electric current to flow. Since there is only one wire, the circuit is considered an open circuit, and the flow of electrons is interrupted. ## Gizmo Warm-up: Build a Circuit 1. **Now try to light the bulb with the smallest number of components.** - The smallest number of components required to light the bulb is one battery, one wire, and one bulb connected in a closed circuit configuration. 2. **Based on what you have seen, what must be true for a circuit to light a bulb?** - For a circuit to light a bulb, it must be a closed circuit, allowing electrons to flow from the battery through the bulb and back to the battery. The circuit must include a conductor to facilitate the flow of current. --- ## Activity A: Closing a Circuit 1. **Predict:** A. **Predicted conductors:** Metal objects (e.g., copper, aluminum). B. **Predicted insulators:** Rubber, wood, plastic, glass. C. **How could you use your open circuit to test if a material is a conductor or insulator?** - You can replace the gap in the open circuit with different materials one at a time. If the light bulb lights up when a material is placed in the gap, that material is a conductor. If the bulb does not light up, then the material is an insulator. 2. **Experiment Results:** - **Conductors:** (List the materials that lit the bulb). - **Insulators:** (List the materials that did not light the bulb). 3. **Analyze:** A. **What kind of material are most conductors?** - Most conductors are metals, as they have free-moving electrons that allow current to flow easily. B. **Did any conductor have a different effect on the light bulb than the others? Explain.** - (Discuss any variations in brightness or other effects if observed; otherwise, note that generally all conductive materials showed similar effects). --- ## Activity B: Series Circuits 1. **Observe:** A. **What do you notice about the brightness of the bulbs as you add more bulbs?** - The brightness of the bulbs tends to decrease as more bulbs are added to the circuit because the total current is divided among all the bulbs. B. **Do all the bulbs have the same brightness?** - Usually, yes; in a series circuit, all bulbs typically have the same brightness, but they may all be dimmer compared to a single bulb setup. C. **Look at the current arrows in each part of the circuit. Are there any parts of the circuit that have more current than other parts?** - In a series circuit, all parts of the circuit have the same current since the current has only one path to follow. 2. **Explore:** - When you remove a light bulb from the series circuit, the remaining bulbs go out because the circuit becomes open. 3. **Extend your thinking:** A. **How does a circuit with a 1.5-volt battery compare to a circuit with a 9-volt battery?** - A circuit with a 9-volt battery will generally cause the bulbs to be brighter than those powered by a 1.5-volt battery due to the higher voltage providing more potential energy for the current. B. **Replace one of the wire segments with another 1.5-volt battery. What happens?** - The voltage in the circuit increases, making the bulbs brighter, similar to what you would find in a circuit with a higher voltage battery. 4. **Compare:** - **What do you notice?** - The series circuit powered by six 1.5-volt batteries provides similar brightness and performance as a circuit powered by a single 9-volt battery. **Why is this true?** - This is true because the total voltage provided to the series circuit is the same (9 volts), regardless of how many batteries are used. --- ## Activity C: Parallel Circuits 1. **Observe:** - Yes, the bulbs are equally bright. Each bulb receives the full voltage across its terminals because they are in parallel. 2. **Experiment:** A. **Did the brightness of the bulbs change?** - No, adding additional bulbs did not change the brightness of the existing bulbs since they all still receive the same voltage. B. **Remove one light bulb. What happens?** - The remaining bulbs remain lit and maintain their brightness, demonstrating the independent pathways in a parallel circuit. C. **How did the parallel circuit respond differently to these changes than a series circuit?** - In a parallel circuit, adding bulbs does not diminish the brightness of existing bulbs, while in a series circuit, adding bulbs decreases total brightness. 3. **Observe:** - When a wire replaces a light bulb, the circuit creates a short circuit, causing the remaining current to increase significantly, which could be very dangerous. 4. **Apply:** A. **What happens?** - The light bulb may blow out or become very bright momentarily before the fuse acts due to excessive current. B. **Create a short circuit. What happens now?** - The current surges, potentially causing the fuse to blow immediately or the circuit to short out, stopping the current flow for safety. C. **How does a fuse make the circuit safer?** - A fuse interrupts the current flow if it becomes too high, preventing excess current that could cause overheating or start a fire.