• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13

Find the relationship between amount of fat and amount of energy produced in different foods.

Extracts from this document...


July 2001 Biology Coursework Year 10 Aim Find the relationship between amount of fat and amount of energy produced in different foods. Planning I am going to ignite different foods and see how much heat energy they give out. The food that causes the biggest amount of change in temperature will have the most amount of energy. However, calculations have to be carried out to create an average energy output per gram. Variables Independent Variables: This will change from food to food, thus giving me a range of different results. In this experiment it will be type of food. Dependant Variable: This is the amount of Energy per gram which can be calculated Controlled Variables: These are the things that will keep the same, in order to sustain a fair test. These are; * Apparatus * Type of boiling tube * Distance of boiling tube from Bunsen burner * Distance of food from boiling tube * Amount of time taken to move ignited food to boiling tube Fair Test It is essential that I keep it a fair test in order to sustain accurate results for comparison at the end. To ensure a fair test, I must keep the controlled variables for every test I do. The apparatus must all be kept the same because there may be some minor differences in insulation properties, or measure of accuracy between them. If this were to happen, it would prevent me from sustaining accurate results. The same type of boiling tube must be kept constant because, every boiling tube may have different conducting properties. If it were not as dense as a previous test tube, it would heat up more quickly, and if it were denser, I would get the opposite affect. This is why it is essential that all the boiling tubes are identical as it could lead to totally false results. The boiling tube must be changed for each test though, because a previous boiling tube may have retained heat from a previous experiment. ...read more.


ENERGY (J/g) PUMPKIN SEEDS 0.1g 16?C 35?C 19?C 20g 1596 15960 0.1g 18?C 48?C 30?C 20g 2520 25200 0.1g 26?C 29?C 3?C 20g 1260 12600 CRISPBREAD 1.1g 15?C 25?C 10?C 20g 840 764 1.2g 16?C 32?C 32?C 20g 1344 1120 1.1g 17?C 29?C 12?C 20g 1008 916 1.1g 19?C 37?C 18?C 20g 1512 1375 Calculations Energy (Joules) = 4.2 x temperature difference x weight of water Energy (Joules/g) = Energy (J) Weight of food Crispbread 1. Energy (J) = 4.2 x 10?C x 20g = 840J Energy (J/g) = 840J / 1.1g = 764J/g 2. Energy (J) = 4.2 x 32?C x 20g = 1344J Energy (J/g) = 1344J / 1.2g = 1120J/g 3. Energy (J) = 4.2 x 12?C x 20g = 1008J Energy (J/g) = 1008 / 1.2g = 916J/g 4. Energy (J) = 4.2 x 18?C x 20g = 1512J Energy (J/g) = 1512 / 1.1 = 1375 Pumpkin Seeds 1. Energy (J) = 4.2 x 19?C x 20g = 1596J Energy (J/g) = 432J / 0.1g = 15960J/g 2. Energy (J) = 4.2 x 30?C x 20g = 2520J Energy (J/g) = 480 / 0.1g = 25200J/g 3. Energy (J) = 4.2 x 20?C x 20g = 1680J Energy (J/g) = 432J / 0.2g = 840J/g 4. Energy (J) = 4.2 x 3?C x 20g = 1260J Energy (J/g) = 480 / 0.1g = 12600J/g Results from Main Experiment FOOD WEIGHT OF FOOD START TEMPERATURE END TEMPERATURE TEMPERATURE DIFFERENCE WEIGHT OF WATER ENERGY (J) ENERGY (J/g) DRIED PEAS 0.49g 22?C 29?C 7?C 20g 582 1200 0.25g 23?C 26?C 3?C 20g 252 1008 SUNFLOWER SEED 0.13g 24?C 34?C 10?C 20g 840 6462 0.15g 21?C 26?C 5?C 20g 420 2800 PASTA 0.33g 22?C 24?C 2?C 20g 168 509 0.30g 24?C 26?C 2?C 20g 168 560 CRISP 1.48g 20?C 33?C 13?C 20g 1092 738 0.86g 24?C 37?C 13?C 20g 1092 1270 Calculations Energy (Joules) ...read more.


This could have been faulty equipment being used. The time taken for the food to be put under the boiling tube once lit was not measured. Therefore I suspect that it was different for every experiment. We did not time it and it was hard to tell when the food was totally ignited. This made the test unfair. Also there was the fact that not all of the energy was being used to heat the water. Some would have been lost. Also, the food is not completely burned. The black residue left behind proves this. Therefore, not all of the energy is used. I don't think there are many ways of improving the accuracy of the experiment large deal. If it were repeated around 5 times for each food, it may prove better because only two comparisons is not very helpful. When an anomaly was present, I often did not know which one was the anomaly, and had to find out via comparison with other pupils' results. Also, a larger range of foods should be tested. Therefore, there would be more means of comparison. The main cause of inaccuracy was the lack of energy reaching the water. To increase this, maybe if the burning food was placed into a metallic container, and the rise in temperature in the atmosphere in the container was recorded, it may be more accurate. However, one way to encourage the complete combustion is to burn the food in a higher concentration of oxygen than normal atmospheric conditions. However, oxygen is pretty explosive so it would require greater safety features and would be done in a controlled environment. That is why experimenting it in a bomb calorimeter, would be most accurate and is how official results are obtained. Bomb calorimeters burn the food in special chamber totally enclosed by the water it is heating. In these the food is burned in pure oxygen as this helps to ensure that it is totally burned and therefore all the energy is released. The experiment that we carried out is an example of a simple calorimeter. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

A good account of the investigation including detailed discussion of unexpected results. There are too many incorrect references to energy being produced or created.

4 Stars

Marked by teacher Adam Roberts 25/10/2014

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    effect of temperature on the rate of respiration in yeast

    5 star(s)

    A redox reaction has taken place. After a second hydrogen carrier, the hydrogen splits in to hydrogen ions and electrons. The hydrogen ions remain in solution in the mitochondrial matrix, whilst the electrons are passed along a series of electron carries. This makes energy available which is used to convert ADP + Pi to ATP.

  2. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    These enzymes break down the sugar into ethanol and carbon dioxide. The optimum temperature for the enzymes in yeast is between 20-30?C. If the temperature is above 50�C then the enzymes will become denatured. If the substrate concentration is increased, the rate of reaction will increase up to a point,

  1. Marked by a teacher

    Biology coursework investigation: Comparing the length of ivy leaves (Hedera helix) in areas of ...

    4 star(s)

    When measuring the leaves, only the frond length (without the petiole) of each ivy leaf will be measured. In order to enable a fair comparison to be carried out between the lengths of the two groups of ivy leaves,

  2. Marked by a teacher

    Studying the Effect of Salt on Cress Germination

    4 star(s)

    Results from the test (fig 5) show that germination in the presence of 1.25 g to 2g (2.5 - 4%) salt concentration is severely inhibited. No concentration of salt appeared to increase the rate of respiration (in comparison to the control).

  1. Free essay

    Biological Importance of Water

    3 star(s)

    In plants, the build up of osmotic pressure helps to disperse the seeds of some plants such as the squirting cucumber and the spores of mosses and ferns can also be carried by water. As a Reagent: Water is vital for a number of metabolic reactions.

  2. Cycles in Biology.

    Carbon is stored in the lithosphere in both inorganic and organic forms. Inorganic deposits of carbon in the lithosphere include fossil fuels like coal, oil, and natural gas, oil shale, and carbonate based sedimentary deposits like limestone.

  1. Yeast Coursework

    This shows how the enzyme makes the substrate molecules react to form a new product. After this takes place, the enzyme remains the same, and repeats this process. The enzyme lowers the amount of energy that is needed for the reaction to take place, making it much more likely to occur.

  2. Effects of exercise on tidal volume and breathing rate

    Calculate the coefficient (R) using the formula below. The answer will always be between 1.0 (a perfect positive correlation) and -1.0 (a perfect negative correlation).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work