When a wave crashes onto a shore you can see white foam splash on the rocks and sand. As the water hits the beach it traps thousands of bubbles of air and they make the water look white. If you have been out in sunny weather you may use a foam to protect your skin. When you press the top of the sun cream cylinder it will rush out as a white foam for you to spread on your skin.

Plastic foam is solid. It has gas bubbles in it. They are made by chemicals that are mixed with the plastic. The bubbles make the plastic very lightweight and make it springy and flexible. Plastic foam is used for making the padding in upholstered furniture. This makes it comfortable to sit on. Plastic foam is also used as a filling for cushions and pillows.

The foam is made of individual bubbles. The video below shows bubbles being made one by one.