Types of food:
There are three types of food-carbohydrates, fats and proteins. We need carbohydrates and fats for energy. We need proteins for growth and repair.
Cornflakes, rise, spaghetti, potatoes, sugar, cakes = carbohydrates
Chocolates, butter, ice-cream, cream, peanuts = fat
Fish, milk, cheese, eggs, Soya protein = proteins
How much energy is given by different foods?
The amount of energy given by a particular food depends on the substances, it contains. For example margarine and butter consists almost entirely of fat, so they give a lot of energy. On the other hand a cabbage is 90% water, so it gives very little energy.
Another thing that determines how much energy a particular food gives of is how it is cooked e.g. potatoes fried in fat give three times more energy as potatoes boiled in water.
A food calorimeter is used to find out how much energy there is in a sample of food:
Prediction
I think that the more energy a food contains then the more hotter the water will be.
The food containing more fats will increase the temperature the most because…
More fats>more energy>rise in temperature
Plan
To investigate how much energy a food sample contains I will need…
Bowling tube
Tongs
Water
Crushed food – crisps, cereal, rice, biscuit, noodles, bread
Bottle top
Thermometer
Bunsen burner
Pestle and mortar
For the whole of the experiment I shall be wearing goggles.
Firstly I am going to fill a boiling tube with 1/3 of water and then I am going to clamp it (see diagram).
Then I shall record the temperature of the water.
Then I am going to crush the food that I shall be using with a pestle and mortar and then place the food in a bottle top.
Then by using the tongs I am going to hold the bottle top in the blue (roaring) flame of a Bunsen burner until the food sets alight.
Whilst the food is burning I will be holding it under the boiling tube of water, once the food has stopped burning I shall use a thermometer to stir the water in the boiling tube and take its new temperature.
Results
Conclusion
From looking at both the graphs and results it shows that crisps had the most amount of energy.
I am not surprised that the noodles contained the least amount of energy, as the noodles don’t have much fat.
Order of energy given out:
Evaluation
I think that the experiment was unreliable. The results were not very accurate due to the not so accurate amount of water and the foods, we could of weighed and made sure that we used the same amount of food for each one. Also we should of left the water to cool down between each food for the same amount of time.
Instead of using a 1/3 of the boiling tubes amount in water we could of used 20ml of water.
There were also difficulties in keeping the Bunsen burner alight and also keeping the food alight long enough to have an effect in the temperature of the water. Also to ensure the Bunsen stays alight and isn’t affected by wind, e.g. place a shield around the Bunsen.
