Lesson 19 – Safety with Light and Sound

Read About Safety with Light and Sound


Read the vocabulary terms to understand the reading better.


A device is a piece of equipment made for a special purpose.


Ultraviolet light is short light waves produced by the sun that cannot be seen by humans.

Safety with Light and Sound

Many devices apply the properties of light and sound. Many of these devices make our lives safer. For example:

UV-coated sunglasses protect our eyes from harmful sunlight.

Safety sensors stop doors from closing on something in the way.

Back-up signals on trucks and cars warn us the vehicle is moving.

Ear plugs protect our ears from loud noises.

Some technologies that use light and sound have disadvantages. For example, talking on a cell phone can be dangerous while walking, biking, or driving. Loud sounds can damage your hearing. Loud sounds can come from music, motors, and nature.

Now Show What You Know!

Complete some questions about the reading selection by clicking “Begin Questions” below.