I predict that at 45 C the rennet will make the milk clot but at 85 C the milk will not clot because the enzyme rennet will be denatured and therefore no work.EquipmentSafety gogglesLab coats6 test tubes2 test tube racks2 water baths, one at 45 C and the other at 85 C8 cm cubed of rennet8 cm cubed of fresh milk2 pipettes4 thermometers2 stopwatches2 measuring cylindersDiagramMethodGet out all of the equipment listed aboveMeasure out 4 cm cubed of milk and put it in a test tubeRepeat this once more putting the milk in another test tubeMeasure out 4 cm cubed of rennet and put this in a different test tube againRepeat this one more putting the rennet in another test tubeThere should still be 2 clean test tubesHeat the milk in one test tube to 45 c and the milk in the other to 85 C using the waterbathsDo the same with the rennetPour the rennet that is heated to 45 c into the test tube of milk, which is also at 45 CPour the rennet that is heated to 85 C into the test tube of milk, which is also at 85 CReplace these 2 test tubes into the water baths at the correct temperaturesEvery 1-minute look at the test tube and record what you can seeRepeat this all again for reliability.ResultsConclusionIn conclusion my prediction was correct.
The milk clots firmly after 8 minutes in the water bath at 45 C but at 85 C it does not clot as the rennet enzyme has been denatured and therefore will not clot the milk. The longer that the milk and rennet was in the 45 c water bath the firmer the clots got. This is because the rennet had a longer period of time to clot the milk. We did not get any anomalous results, which shows that our results are quite accurate. This is shown on the two graphs.
EvaluationIf I had chance to perform this experiment again I would repeat the results for reliability, I did not do this because I ran out of time but with more time this would be able to be completed. I also stopped recording the affect of the rennet on the milk after 8 minutes but I should have done this for half an hour as the teacher suggested it.