Foam is a substance produced by some kind of liquid that forms bubbles. Foam is commonly found in natural areas where there is a lot of water. It’s also found in some cleaning products and in certain types of drinks such as beer:
Beer foams when it is poured into a glass. (This sentence uses "foam" as a verb.)
Beer develops a head of foam after it is poured into a glass. (This sentence uses "foam" as a noun.)
Beer can be too foamy if it isn’t poured properly. (This sentence uses "foamy" as an adjective.)
Coca-cola foams when it’s poured over ice.
We noticed there was a lot of foam along the shoreline when we sent swimming yesterday.
When water rolls in along the shoreline from the ocean or from a large lake, it looks like it’s foaming.
If you spray water into a container that has a lot of soap, foam will form on the surface of the water.
If a dog is foaming at the mouth, it might be really sick.
If a person is foaming at the mouth, he or she might be really angry or crazy. ("Foaming at the mouth" is a figure or speech used for people who are very mad. They’re really isn’t foam coming from the mouth.)