The concept of storing energy is fundamental to much of this course.

Lets start with a simple example of storing energy in a cross bow.

• Crank the string back on the bow, and energy is stored in the tension of the sting and lath.
• Release the energy by pressing the trigger

Photosynthesis begins the process by using chlorophyl and enzymes to store the sun's energy in the form of sugar molecules in plants.  Carbon dioxide (CO₂) and water (H₂O) are used by the plant to build a simple sugar.  During photosynthesis the sun's energy is stored in the chemical bonds holding the atoms together (the dash lines in the glucose molecule below).

How many chemical bonds are storing energy in this glucose molecule? _________.

If a glucose molecule contains 190 calories, how much energy is stored in each bond? ____ cal.

Energy stored in a chemical, such as glucose, is called "chemical energy."

Careful how you release the energy.  If you used a match to heat this glucose molecule up, as soon as the first bond broke, the breaking would cause a small explosion and flame.  This flame would be hot enough to break the adjacent bonds, and soon the molecule would burn on its own and you could blow out the match.

Examples of the use of chemical energy:

• All of the daily activities of your body are powered by the organic molecules you eat.  Add up the calories you eat in a day, and that is a good measure of how much energy your body uses in a day.
• Throw a log on the fire; the heat and light are both released chemical energy that was stored in the bonds of the cellulose molecules making up the wood.
• Timothy McVeigh made a bomb out of drums of sugar mixed with other organic molecules.  When he set the bomb off, the Federal Building in Oklahoma City was destroyed with terrible loss of life, pain and suffering.  The point is, this chemical energy is big time energy.