Evaluate the method for this investigation. Think about which factors have been controlled to make it a fair test. Consider whether any factor other than temperature could be responsible for the colour leaking from the beetroot cores. Do you think this experiment will give you valid results? Describe how you could improve the experiment to give more reliable (or more valid) results.
The factors controlled in this test are the ones that are the same from one group to another – the size of the beetroot cores (their surface area and volume), the advance treatment of the beetroot cores, the volume of water in the test tubes, the pre-heating (or chilling) of the water in the test tubes using the water baths, the length of time the cores spend in the water baths, the treatment of the cores after heating. The experiment could be made more reliable by using more samples of beetroot, and by maintaining the temperature with thermostatically-controlled water baths.