1. Agenda 9.12.07 ► Mentos Lab (25 minutes)  Write your objectives in your science notebooks ► Energy Conversion & Energy Conservation Discussion  Finish copying the examples of “Energy Conversion from the White Board” (Write these examples on page 16.) ► Objective  Students will be able describe what energy conversion is taking place after a mentos is dropped into a diet coke.

2. Objectives: 9.12.07 (Pg. 17) ► The students will make observations that describe what happens when a mentos is dropped into a 2 liter of diet coke. ► The students will describe or explain the energy transfer that occurs when a mentos is dropped into a 2 liter of diet coke. ► The students will make predictions about variables that can change the height of the soda geyser.

3. Energy Conversion and Conservation ► The law of conservation of energy states that energy cannot be created nor destroyed. It can only be converted or transformed from one form to another. ► For example when an object is falling, the potential energy is being converted into kinetic energy. ► We must not forget that there are different forms of energy. They are mechanical, electrical, electromagnetic (light), nuclear, sound, thermal (heat), and chemical energy. ► Whenever we use an appliance, the appliance uses one of the sources of energy as a primary source of energy. While the primary source of energy is being used to run the appliance, it is also being converted into a new form of energy. ► For example, a stove uses electrical energy and converts it into heat or thermal energy so that we can cook our food.

4. The Mentos Activity ► Before 1.What do you think will happen when you place a mentos candy in a bottle of 2 liter diet coke? 2.Why do you think this will happen? ► After 1.What happened when you placed the Mentos candy in the 2 liter coke bottle? 2.Try to explain what’s really causing this soda geyser to erupt. 3.Trace the energy transfer throughout this energy system.

5. The Mentos and Diet Coke Explanation ► When placing a mentos candy into a 2 liter of diet coke, you will witness a violent reaction taking place, in which, the soda fizzes and exits the bottle like an explosive volcano. ► Why does this happen? The mentos candies have pits all over them, although you can’t see them. When the candy is dropped into the carbonated liquid, the candy reduces the solubility of Carbon Dioxide gas. The Carbon Dioxide gas forms on these pits and then is released, quickly. The Carbon Dioxide gas is trapped in the form of bubbles and is released at such a rate that pressure in the bottle builds up at an exponential rate and then is released through the opening of the bottle. ► The chemical energy is transferred from the mentos candy to the Carbon Dioxide gas, in the form of thermal energy since this reaction is happening on a molecular level.

6. Homework ► In your composition notebook, draw an illustration that shows the energy conversions taking place when dropping a mentos candy in a bottle of soda. ► In your composition notebook, draw an illustration that shows the energy conversion taking place rolling a marble down a ramp.