U 10 Lesson 3 What Is an Electric Circuit?

Sidney wants to make an electric circuit. She gathers the items shown below.

What additional item does Sidney need to make a complete circuit?

• a battery

• a conductor

• an insulator

• a switch

Clayton tries to build an electric circuit using a battery, a light bulb, a paper clip, and copper wire. The diagram below shows what he builds.

Which statement best explains why the circuit would not conduct electricity?

• The circuit lacks a power source.

• The paper clip stops the electric current.

• The light bulb uses the electric current.

• The circuit is not a complete loop

Roberto makes an electric circuit that has a switch as one of its parts. The diagram below shows the circuit that he makes.

What would happen to the light bulb if Roberto changed the switch from closed to open?

• It would be duller.

• It would start glowing.

• It would stop glowing.

• It would be brighter.

Sara arranges the parts of a circuit as shown below.

Where should Sara put a piece of wire in order to complete the circuit?

• between the top of the battery and the top of the paper clip

• The paper clip stops the electric current.

• between the top of the paper clip and the bottom of the battery

• . between the top of the battery and the bottom of the light bulb

Which of the following items would work best to complete a circuit?

• metal coin

• wooden toothpick

• plastic straw

• glass bead

Serena is building an electric circuit. She will use it for a science project. Which of the following does Serena need for electricity to flow through the circuit?

• The circuit needs a light bulb.

• The circuit must be a complete loop.

• The circuit must be open at one end.

• The circuit needs an insulator.

Courtney wants to know if a wooden craft stick can be used to close a circuit that turns on a light bulb. Which observation would show that wood does not conduct electricity?

• The bulb lights for a short time and then goes out.

• The bulb flickers on and off.

• The bulb lights brightly.

• The bulb remains unlit.

A key lists the symbols used for the parts of the circuit diagram shown below.

What is the purpose of the battery in the circuit?

• to use the electric current

• to slow the flow of electricity

• to provide a source of energy

• to connect the components

Ryan has a circuit made up of a battery, a light bulb, some wires, and a metal rod as a switch. Ryan replaces the metal rod with a wooden rod. When he closes the new switch, what will Ryan most likely observe?

• flashing bulb

• brighter bulb

• unlit bulb

• warmer bulb

Joy builds an electric circuit out of several pieces of wire, a light bulb, and a battery. Now she wants to add a switch to the circuit. Which of the following would be best to use for a switch?

• a cotton string

• a wooden stick

• a plastic spoon

• a metal paper clip