picture of a soda in a flask.  It shows bubbles from gas escaping from the soda.

Source: Combining Pop Rocks with Sprite inflates a balloon, posted by Loralee, Candy Experiments

The three states of matter we are addressing in this lesson are solid, liquid, and gas.

There is a fourth state of matter called plasma. Plasma is a highly ionized gas composed of ions, electrons, and neutral particles. In this lesson, however, our focus will be on solids, liquids, and gases.