LAB: ENERGY inside a peanut

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INTRODUCTION

 

Every thing has energy in it. (after all E = mc²). Potential energy is the stored energy of an object due to its ____________ (see lesson). This potential energy can be transferred into another form of energy like energy of motion and heat.

 

For example, a tiny peanut contains stored chemical energy. When we eat it, te stored energy is converted bu our body so we can do __________. The energy contained in a peanut can be used to heat a container of water.

 

PURPOSE:

In this activity, you will determine measure the temperature of water before and after a peanut is burned to determine how much energy is in a single peanut.

 

PLEASE be careful not to cut yourself on the metal cans. Also, be careful with the fire.

 

PROCEDURE

 

Step1: Carefully push the eye of the needle into the smaller end of thhe cork.

 

Step2: Gently push the pointed end of the needle into a peanut. Be careful not to push too hard, because the peanut will break. If the peanut breaks, use another one. It should look similar to the picture below.

 

 

 

 

PLEASE TAKE TIME TO READ THE INTRODUCTION

Don’t jump on the lab part
FILL THE BLANK FOR FULL CREDIT

ANALYSIS

 

1) Fill the TABLE

 

2) Calculate the number of calories transferred from the peanut to the water for each trial using the following equation: (thermal energy)

 

Heat = s . m . ΔT

Where: s = the specific heat of water = 1 cal/g ºC

m = mass of water

ΔT = change in temperature

 

 

 

2) The calories you count when you are dieting are kilocalories. How many kilocalories are there in each of your peanut ?

 

3) Compare the quantity you found with the Calories inside a can of soda (about 200 Kcalories).

 

4) How much heat is required to raise the temperature of 70g of water from 20C to 80C?

 

5) How much heat must be removed from a 200g block of copper to lower its temperature from 150C to 30C ? The specific heat of copper is 0.093 cal/gC ?

Step3: Weigh an empty 200ml beaker. Fill it about half way with room temperature water and weigh it again.

 

Step4: Clamp the beaker to a ring stand amnd place the cork (with the peanut attached) on the base of the ing stand.

 

Step5: Take the initial temperature of the water and record it on in TBALE1 (should be around 25C)

 

Step6: Carefully light the peanut on fire. Be sure the ENTIRE peanut is charred and on fire.

 

Step7: As soon as the peanut has caught fire, immediately place a coffe can cylinder around the nut/ Be sure the holes are on the bottom of the coffee can.

 

Step8: Lower the beaker so that is close to the flame coming from the peanut.

(see picture below).

 

Step9: Let the peanut burn until it goes out. The bottom of the beaker may becole charred.

 

Be careful not to touch the black charcoal from the peanut and the beaker !

Step10: Once the peanut goes out, take the final temperature of the water.

 

Step11: Repeat the experiment a second time and record the data. Make sure you let the beaker cool down before you start. (or take another one)