Agenda 9.12.07Agenda 9.12.07

► Mentos Lab (25 minutes)Mentos Lab (25 minutes) Write your objectives in your science notebooksWrite your objectives in your science notebooks

► Energy Conversion & Energy Conservation Energy Conversion & Energy Conservation DiscussionDiscussion Finish copying the examples of “Energy Conversion Finish copying the examples of “Energy Conversion

from the White Board” (Write these examples on page from the White Board” (Write these examples on page 16.)16.)

► ObjectiveObjective Students will be able describe what energy conversion Students will be able describe what energy conversion

is taking place after a mentos is dropped into a diet is taking place after a mentos is dropped into a diet coke. coke.

Objectives: 9.12.07 (Pg. 17)Objectives: 9.12.07 (Pg. 17)

►The students will make observations that The students will make observations that describe what happens when a mentos describe what happens when a mentos is dropped into a 2 liter of diet coke. is dropped into a 2 liter of diet coke.

►The students will describe or explain the The students will describe or explain the energy transfer that occurs when a energy transfer that occurs when a mentos is dropped into a 2 liter of diet mentos is dropped into a 2 liter of diet coke. coke.

►The students will make predictions about The students will make predictions about variables that can change the height of variables that can change the height of the soda geyser. the soda geyser.

Energy Conversion and Energy Conversion and ConservationConservation► The law of conservation of energy states that energy The law of conservation of energy states that energy

cannot be created nor destroyed. It can only be cannot be created nor destroyed. It can only be converted or transformed from one form to another. converted or transformed from one form to another.

► For example when an object is falling, the potential For example when an object is falling, the potential energy is being converted into kinetic energy. energy is being converted into kinetic energy.

► We must not forget that there are different forms of We must not forget that there are different forms of energy. They are mechanical, electrical, energy. They are mechanical, electrical, electromagnetic (light), nuclear, sound, thermal electromagnetic (light), nuclear, sound, thermal (heat), and chemical energy. (heat), and chemical energy.

► Whenever we use an appliance, the appliance uses Whenever we use an appliance, the appliance uses one of the sources of energy as a primary source of one of the sources of energy as a primary source of energy. While the primary source of energy is being energy. While the primary source of energy is being used to run the appliance, it is also being converted used to run the appliance, it is also being converted into a new form of energy. into a new form of energy.

► For example, a stove uses electrical energy and For example, a stove uses electrical energy and converts it into heat or thermal energy so that we converts it into heat or thermal energy so that we can cook our food. can cook our food.

The Mentos ActivityThe Mentos Activity

► Before Before 1.1. What do you think will happen when you place a What do you think will happen when you place a

mentos candy in a bottle of 2 liter diet coke? mentos candy in a bottle of 2 liter diet coke? 2.2. Why do you think this will happen?Why do you think this will happen?

► AfterAfter1.1. What happened when you placed the Mentos What happened when you placed the Mentos

candy in the 2 liter coke bottle?candy in the 2 liter coke bottle?2.2. Try to explain what’s really causing this soda Try to explain what’s really causing this soda

geyser to erupt. geyser to erupt. 3.3. Trace the energy transfer throughout this Trace the energy transfer throughout this

energy system. energy system.

The Mentos and Diet Coke ExplanationThe Mentos and Diet Coke Explanation

► When placing a mentos candy into a 2 liter of diet coke, When placing a mentos candy into a 2 liter of diet coke, you will witness a violent reaction taking place, in which, you will witness a violent reaction taking place, in which, the soda fizzes and exits the bottle like an explosive the soda fizzes and exits the bottle like an explosive volcano. volcano.

► Why does this happen? The mentos candies have pits all Why does this happen? The mentos candies have pits all over them, although you can’t see them. When the candy over them, although you can’t see them. When the candy is dropped into the carbonated liquid, the candy reduces is dropped into the carbonated liquid, the candy reduces the solubility of Carbon Dioxide gas. The Carbon Dioxide the solubility of Carbon Dioxide gas. The Carbon Dioxide gas forms on these pits and then is released, quickly. The gas forms on these pits and then is released, quickly. The Carbon Dioxide gas is trapped in the form of bubbles and Carbon Dioxide gas is trapped in the form of bubbles and is released at such a rate that pressure in the bottle builds is released at such a rate that pressure in the bottle builds up at an exponential rate and then is released through the up at an exponential rate and then is released through the opening of the bottle. opening of the bottle.

► The chemical energy is transferred from the mentos candy The chemical energy is transferred from the mentos candy to the Carbon Dioxide gas, in the form of thermal energy to the Carbon Dioxide gas, in the form of thermal energy since this reaction is happening on a molecular level. since this reaction is happening on a molecular level.

HomeworkHomework

► In your composition In your composition notebook, draw an notebook, draw an illustration that shows illustration that shows the energy conversions the energy conversions taking place when taking place when dropping a mentos dropping a mentos candy in a bottle of candy in a bottle of soda. soda.

► In your composition In your composition notebook, draw an notebook, draw an illustration that shows illustration that shows the energy conversion the energy conversion taking place rolling a taking place rolling a marble down a ramp. marble down a ramp.