http://www.ck12.org Chapter 2. Matter
FIGURE 2.36
FIGURE 2.37
Q:What happened to the chocolate?
A:The chocolate melted. It changed from a solid to a liquid.
In order for solid chocolate to melt and change to a liquid, the particles of chocolate must gain energy. The chocolate
pictured in theFigure2.37 gained energy from sunlight. Energy is the ability to cause changes in matter, and it is
always involved in changes of state. When matter changes from one state to another, it either absorbs energy—as
when chocolate melts—or loses energy. For example, if you were to place the melted chocolate in a refrigerator, it
would lose energy to the cold air inside the refrigerator. As a result, the liquid chocolate would change to a solid