# Design and carry out an experiment to find out the energy content of various foods.

SC1 Investigation

## Problem

For this piece of coursework, I intend to design and carry out an experiment to find out the energy content of various foods.

## Method

For my experiment I have chosen four different foods that I will test for energy content, they are sweetened banana chips, toffee popcorn, original flavour Hula Hoops and salted peanuts. I will use the following apparatus and will set it up as shown:

For the experiment all I am going to have three variables, the food that I use, temperature of the water and the weights of the food won’t all be equal, everything else will be kept the same, the distance of the candle from the test tube, the amount of water in the test tubes, etc.

I will fill the test tube with 25cm3 of water using a measuring beaker. I will do three or four tests of each food as to obtain an accurate result and a good average. For each specimen I will find the starting weight, and the starting temperature of the water in the test tube. For the actual experiment I will start off by attaching the food to a spike and then setting it alight by the use of a candle. I will need to make sure that the candle is not too far nor too close to the test tube so as it won’t affect the temperature of the water. As soon as the piece of food is alight I will quickly move it over to under the test tube so that not too much energy is lost during the period of movement between the test tube and the candle. I will hold the item of food under the test tube until the flame goes out, continuously stirring the water so as I don’t get what is called a thermocline (when the water forms layers due to differences in temperature), with a warm layer and a colder layer of water. Once the piece of food has burnt out, I will check the temperature of the water once again and record it. Next I’ll weigh the food and record this as well. Finally, for the calculations to find out how much energy each food has in kJ I will use the following equation:

Temperature rise in oC * Volume of Water in cm3 * 0.0042 = Energy content in kJ

This gives you the amount of kJ per however much the food weighs but I want to find out how many kJ there are per 100g so I will do the following:

100/Weight Burned * Energy content = Amount of kJ per 100g

I will do this for all three tests and then find the average (All results added together divided by number of results). Then I will follow all of these tests for the other three foods.

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