Lighthouses are used as guides for boats, ships and small planes. They help keep ships safe from dangerous coastlines and shallow water.

The earliest lighthouses used fire or candles for light. Next came lamps that burned oil. These lamps were placed in a reflector. Reflectors made the light brighter. Now many lighthouses use electric lights.

Sound is a kind of energy that we can hear.

Sound energy is made when objects vibrate. When an object vibrates, it moves back and forth quickly. When something vibrates, air around the object vibrates too.

The ear collects the sound energy results in vibrations of the eardrum. These vibrations are sent to the brain and the brain tells you what sound you heard.

Not all sounds are the same. Some are loud, others are soft. Small vibrations make soft sounds, big vibrations make loud sounds.

Pitch is how high or low a sound is. Fast vibrations make sounds with a high pitch. Slow vibrations make sounds with a low pitch.

Shorter strings make high pitch sounds, long strings make low pitch sounds.

Most sounds you hear move through air. Air is made of gases. The closer you are to a sound, the louder it sounds. The farther you are from a sound, the softer it sounds.

Sound can move through solids and liquids too.

We use light to see things. Light is a kind of energy. You see things when light reflects, or bounces off the things around you. The reflected light enters our eyes then we can see the objects.

The light may be from the sun, lightbulb or a flashlight.

White light consists of all the colors and we can use a prism which bends the light and all the colors become visible.

A prism is a glass object that can make light bend.