63 Measuring Calories

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63 Measuring Calories Key Vocabulary calorimeter calorie Calorie endothermic exothermic

63 Measuring Calories Watch the teacher demonstration Where did the light energy come from? Record your ideas in your notebook.

63 Measuring Calories What are some other chemical changes that release energy? Share your ideas with the class.

63 Measuring Calories Look at the nut Does the nut have any potential energy? Discuss your thoughts with the class.

63 Measuring Calories How can we release and measure this stored energy from the nut? Share your thoughts with the class.

63 Measuring Calories Read the introduction and look for key ideas

63 Measuring Calories How many Calories are in a nut?

63 Measuring Calories Safety Be sure to wear safety goggles during this investigation. Long hair must be tied back, and loose sleeves rolled up. If anything besides the nut starts to burn, inform your teacher immediately. Be especially careful not to get clothing or your hair near the flame. Make sure to keep a cup of water close by the experiment as a fire- safety precaution. Notify your teacher if you are allergic to nuts. The can may become quite hot. Carefully follow all instructions from your teacher.

63 Measuring Calories Complete the procedure Calculate, in calories, the amount of heat energy the water gained by using this formula: energy released (calories) = temperature change of water (°C) x mass of water (g)

63 Measuring Calories Share your results with the class What can account for the lower value in your results? Share your thoughts with the class.

63 Measuring Calories Analysis question 1 How many Calories were in your nut? Show your calculation.

63 Measuring Calories Analysis question 2 Explain, in terms of energy transfer and transformation, what caused the temperature of the water to change.

63 Measuring Calories Analysis question 3 Was all of the energy from the burning nut transferred to the water? If not, explain what happened to the energy that was not transferred to the water.

63 Measuring Calories Analysis question 4 How would you improve the design of this calorimeter so that it would work better? a. Draw a detailed, labeled diagram of your improved calorimeter. Be sure that you could build it yourself, if you had the materials. b. Explain why your design is better than the one you used.

63 Measuring Calories Analysis question 5 If you burned a puffed cheese snack of the same size as the nut, would you get the same result? Why or why not?

63 Measuring Calories Analysis question 6 A curious student wanted to know if the calorimeter would work with different amounts of water. The table below shows the results from her burning three nuts of the same type and mass, but using varied amounts of water in the can. Explain from the table below whether the calorimeter measured the energy in the nut properly when used with each amount of water.

63 Measuring Calories SCORING GUIDE: Analyzing Data

63 Measuring Calories How many Calories are in a nut?

63 Measuring Calories Key vocabulary definitions Calorimeter - A device that measures the amount of chemical potential energy in a material. calorie - A measure (unit) of heat energy. Specifically, it is the amount of energy needed to raise one gram of water one degree Celsius.

63 Measuring Calories Key vocabulary definitions Calorie – 1,000 calories. Endothermic - A chemical reaction characterized by the absorption of heat. Exothermic - A chemical reaction characterized by the production and release of heat. See endothermic reaction.

63 Measuring Calories Experiment With your teacher’s permission, measure the temperature change caused by burning a marshmallow or a puffed cheese snack.