Food provides us with the energy we need to grow, move, think and for many other vital reactions in our bodies. This energy is stored in chemical bonds in the food molecules and released in our bodies when we need it. This energy is released slowly in our bodies but more quickly if the food is burnt it air. This heat energy can be used to heat water. Some foods store and can release a lot more energy than other foods.
The aim of this investigation is to contrast the amount of energy stored in a selection of foods.
To make this a fair test I am going to use the same digital thermometer each time, I will also keep the food the same distance away from the boiling tube, keep the bunsen burner on the same heat and use the same measuring cylinder each time I measure out the water.
ÃÂ·Stand and clamp
ÃÂ·5 different foods
At the start I am going to record the start temperature of the water, then I will burn the piece of food and then place it under the boiling tube, filled with 20cm3 of water. When the flame on the food has burnt out I will then take the temperature of the water in the boiling tube and record it in my results table. I shall repeat this 3 times for each of the foods. Then I will find the average of all 3 results and find out how much energy has been burnt, put it into a separate table and then I will then be able to complete a graph.
I will investigate 5 different foods. They will be:
I chose this number of foods so I have a lot of foods to compare with the other foods and work out what type of foods burn more energy. I chose these foods because they are a wide variety, some are fatty foods and some are full of protein.
I predict that the foods with more fat in such as wotsit, biscuit and tortilla will burn off more energy than the other foods.
Tables of Results
Temperature of the water
FoodFood (g)Start Finish temp rise
Pasta1.4 23.9 27.6 3.7
1.4 25.5 40.6 15.1
1.4 26.4 40 14.2
Wotsit0.3 23.3 26.1 2.8
0.2 25.3 25.5 0.2
0.3 24 31.1 7.1
Biscuit0.8 23.6 41.7 18.6
0.6 25.5 35.2 9.7
0.6 23.5 29.4 5.9
Tortilla0.5 24.7 31.8 7.1
0.3 24.7 29.9 5.2
0.3 26.4 28.9 2.5
Bread1.2 24.2 25.5 1.3
1.4 25.6 27.9 2.3
1.3 24.9 26.4 1.5
FoodEnergy burned (Kj)
Temperature of the water
Before I start the experiment I will put on an apron, a pair of goggles, tie my hair back, tuck my tie in and check all the equipment is useable and in good condition.
My prediction was correct, but it some ways it was incorrect because the food that burnt more energy than the tortilla and wotsit was the bread, which was unexpected. But the biscuit was the food that burnt off the most energy. The pasta was the food that had burnt off the least amount of energy. The only pattern I noticed were that in my graph it rapidly went up then steadily went up. I think that my findings were fairly accurate because I repeated the method three times and all three results were close to each other.
My plan was a good way of getting the information that I wanted to know because nothing in my plan went wrong and all went along how it should of, so I think I got the results I needed. I also think my method got me quite accurate results because I used a digital thermometer and it gave and answer to a decimal place. Another reason why it was accurate was because I repeated it 3 times, and then found an average of all the results, so I got close readings.