The rise in temperature is called global warming . Acid Rain Air pollution also causes acid rain . Rainwater picks up particles and gases when it falls through the air. If the air is polluted, the rainwater becomes polluted, too. Polluted rain is called acid rain .
Some acids are helpful.
We have acid in our stomachs to break down and digest food. We use vinegar, an acid, to pickle cucumbers. Acids like these are help us. But, acids can also be harmful. If there is too much acid in garden soil, plants will not grow.