Circuits and , Motion, and

Two Kinds of Current Lexile 750L

1 Look around you and name five things that use . What are they?

2 Many things use electricity, but not all electricity is the same. There are two very different kinds of electricity.

3 The first kind of electricity is called direct current, or DC. It is called direct because it flows from the energy source to the device that uses it. Devices that use batteries get their energy from direct current. They are powered by this kind of electricity. and cameras are examples of devices that use direct .

4 A device that uses DC energy has a source with a positive side and a negative side. Look at a closely. You will find that it has a positive and negative side, too. When putting batteries into a , you have to be careful to match the sides correctly, or else the flashlight will not .

5 The other kind of electricity is called alternating current, or AC. Power plants produce this type of electricity. It is carried by large power lines from the plant to your home. When you plug a TV, a lamp, or a hair dryer into the wall socket, you are using this type of electricity.

6 AC energy cannot go right into TVs and lamps because it is too powerful. It first needs to pass through a . A transformer breaks the electricity down into smaller parts. The transformer sends just the right amount of energy to your home. This prevents your alarm from burning up!

7 Now look around you once again. Can you tell which things use DC electricity and which use AC electricity?

1 Circuits and Electricity Force, Motion, and Energy

1 The author organized this passage by:

A Contrasting DC and AC currents

B Describing the sequence of how power gets to your home

C Explaining the many uses of electricity

D Telling you the steps to create a circuit

2 Which of these household items is powered by alternating current?

A A flashlight

B A remote control

C A hair dryer

D A handheld video game

3 “A transformer breaks the electricity down into smaller parts. It sends just the right amount of energy into your home.” (sixth paragraph)

Why would a device start burning without the transformer?

A It would not work, and so people might throw it in the fireplace.

B The current would be so powerful that it would cause the device to catch on fire. C You would not be able to tell which way to plug in the device, so there would be a spark on the . D The battery would explode.

2 Circuits and Electricity Force, Motion, and Energy

4 What should go in the empty box?

Electricity is produced at a plant

The transformer breaks the energy into smaller parts

A The energy is stored in a battery.

B You plug in your toaster to use energy.

C , coal, , or nuclear plants generate electricity.

D The electricity travels through power lines.

5 Which of the following statements is true of DC and AC currents? They:

A Have positive and negative sides

B Provide power to devices when they are plugged into a wall socket C Are useful in homes

D Would not work without a transformer

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