Matter is everything that has a volume. Matter is anything that takes up any amount of space. There are only 5 states of matter in the universe, condensation, solids, liquids, gases and plasmas. To remember t the changes of states, you can think of what is similar to it or something easier to remember like a song. The kinetic molecular theory is composed of five postulates, one of which states that gas particles are in constant random motion and it remains in random motion unless acted upon by an outside force. Another rule is that the volume gas molecules occupy is negligible when compared to the volume of the container in which they exist. A third rule posits that when gas molecules collide, there is no loss or gain of energy. Another rule states that there is no notable force of attraction between gas particles.  I learned from the bag of change lab that the colors change because indicators are chemicals that change color when chemicals react. In this case when the calcium chloride and baking soda dissolved into a liquid, they reacted to form an acid which was a different color.