How Temp Affects Rate Of React Essay

, Research Paper


In this investigation I am trying to find out how the temperature of water affects the reaction rate between amylase and starch. The thing that I am going change are the temperature of water, which are 10. C, 20. C, 30. C, 40. C, 50. C. The things I will measure are the colour of the mixture in the present of iodine each minute until it stays a constant brown. I researched this information in a previous lesson in which we did the experiment at one temperature and timing the amount of amylase to break down the starch. Amylase, a carbohydrase found in saliva, works best in slightly alkaline conditions at a pH of about 7.5. I think this information applies to everyday life because it gives us the information about what temperature starch is used in our body.


I predict that the 40.C experiment will be the fastest to breakdown the starch into sugar. The scientific reasons why I think this might be is because 37.C is our bodies temperature and analyse is a biological enzyme in our body so it would work best at 37.C. However, as I do not know how amylase will react at a higher temp and I know that any temp below around 40.C works slower so I think that it will be faster at the highest temperature.


200ml beaker

Test Tube




Spotting tile

Stop Clock


Measuring Cylinder






Step by Step:

1) Collect Equipment

2) Fill beaker with 200ml water at the specified temperature

3) Put 5ml starch, 1ml amylase into test-tube and place in water

4) Start the Stop clock

5) While waiting for 1st minute fill spotting tile with iodine

6) At the each minute interval fill one spot to see colour using pipette

7) Repeat until colour does not change

8) Try again for different temperatures

9) Record results

10) Pack away equipment

I will take measurements every minute. I will make them accurate by carrying out the experiment as safely and carefully as possible. I will use the same amount of iodine amylase and starch in each experiment. I will vary the temperature of the water. I will make it a fair test by taking measurements on the exact minutes adding the same amount of liquids.


1st set of results

Time (min)

Temp 1 2 3 4 5 1 over t

10.C Black Black Black Black Black 1/5 = 0.2

20.C Black Black Drk Brown Tan Tan + = 0.25

30.C Drk Brown Brown Tan Tan Tan + = 0.5

40.C Drk Brown Brown Tan Tan Tan + = 0.5

50.C Black Drk Brown Tan Tan Tan 1/3 = 0.33

2nd set of results

Time (min)

Temp 1 2 3 4 5 1 over t

10.C Black Black Black Black Black 1/5 = 0.2

20.C Black Drk Brown Drk Brown Brown Brown + = 0.25

30.C Drk Brown Tan Tan Tan Tan + = 0.5

40.C Black Drk Brown Tan Tan Tan 1/3 = 0.33

50.C Black Drk Brown Brown Tan Tan 1/3 = 0.33

These results tell me that 30.C – 40.C was the quickest temperatures to make the starch breakdown. My conclusion disagrees with my prediction because I said that the higher the temp the faster the starch would be broken down. The reason for this is because amylase is a biological enzyme which beaks apart when they get too hot, this is when the amylase denatures. Our body temp is around 37.C so this is the best for the starch to work at.

As you can see I have done two graphs. The first one shows how long the starch and amylase took to react at each temp on both set of results but the second graph shows the rate of reaction using 1 over t. I did this second graph to find the optimum temp and this worked out to be 32.C. This shows that my results are not as accurate as they could be because the optimum temperature should be around 37.C.


My results were not as accurate as they could be because the optimum temperature should have worked out to be 37.C. I think this might be because I did measurements at every minute and if I done measurements at every half-minute they would be more accurate and show a better set of results. Having found out that my optimum temperate was 32.C it was an unexpected result to me. I could improve the test by repeating it once more and also taking measurements every 30 seconds. Another test I could do is to test other enzymes in our body and see the results for them.