Circuit Builder Gizmo Answer Key

Name: Rogelio West Date: 12-04-2022 Student Exploration: Circuit Builder Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. 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? They use electricity. 2. Suppose you connect a battery to a small light bulb with a single wire. What do you think will happen? Explain your answer. The wire doesn't need to be connected on either side. 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? Two wires, a lightbulb, and a 9-volt battery with both sides attached to the circuit are all that are required. Get the Gizmo ready: Activity A: ● Click Clear. ● Turn on Show current and select Electron flow. ● Set up components as shown to the right. Closing a circuit 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? Silver, Pencil Lead, Brass and Copper Which are insulators? Glass, Wood, Plastic and Yarn A. Predicted conductors: Silver, Pencil Lead, Brass and Copper B. Predicted insulators: Glass, Wood, Plastic and Yarn C. How could you use your open circuit to test if a material is a conductor or insulator? With a 9-volt battery, a wire, a light bulb, and one of the wires, create a simple circuit. It is a conductor if the bulb illuminates. It is an insulator if it is dark. 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 Pencil Lead Wood Iron Glass Silver Plastic Brass Yard Copper 3. Analyze: Look at your list of conductors. A. What kind of material are most conductors? Metals B. Did any conductor have a different effect on the light bulb than the others? Explain. Because pencil lead (graphite) conducts electricity as a result of the "spare" electrons being delocalized between the layers, the bulb was brighter when Iron, Silver, Brass, or Copper was used as the conductor. So, while it's an excellent conductor, it's not quite as good as the others. Get the Gizmo ready: Activity B: Series circuits ● 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? Because there is more electricity attempting to be distributed, the brightness decreases as you add more bulbs. B. Do all the bulbs have the same brightness? Yes 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? They all have the same number of currents, though. 2. Explore: Now remove a light bulb from your series circuit, leaving a gap. What happens to the remaining bulbs? Due to the fact that they are connected in series, if one malfunctions the others also stop working. 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? The brightness of the bulbs is decreased because there is less electricity. B. Replace one of the wire segments with another 1.5-volt battery. What happens? The light bulb becomes brighter as a result of the increased power 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? Each battery in six is 1.5 volts. The voltage will be 9 if there are 6 batteries present, giving both light bulbs the same level of brightness. As they are both 9 volts, it will be the same as the 6 batteries. Why is this true? Due to the identical brightness provided by each circuit, it will be the same for both circuits. Get the Gizmo ready: Activity C: Parallel circuits ● 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? Both of the light bulbs are equally lit 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? No B. Remove one light bulb. What happens? Nothing the lights stay the same brightness C. How did the parallel circuit respond differently to these changes than a series circuit? Adding bulbs: Parallel circuits will have identically glowing lights. But in series circuits, each bulb's brightness varies. Removing bulbs: In a parallel circuit, when a bulb is removed, the remaining bulbs continue to shine at the same brightness. In a series circuit, however, the brightness of each bulb increases. 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? It shorts out because a connection was made between two electrical circuit nodes that were meant to be at different voltages. 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? Nothing B. Create a short circuit. What happens now? The fuse blows C. How does a fuse make the circuit safer? If an appliance malfunction results in an excessive current flow, the fuse shuts off the circuit. If something goes wrong, this safeguards both the wiring and the appliance.