chemistry

[happyhammy]

hypothesis: 'The rise in temperature of a fixed volume of water is proportional to the mass if solid fuel burnt'
In my experiment I used 1cm3 ,1.5cm3, 2cm3,2.5cm3 of hexamine fuel blocks to burn under a glass beaker with 100ml of tap water.
This experiment was really simple but I am just stuck on the controls for this experiment. it is 6 marks and it is asking for you to identify a range of variables appropriate to control. and also to give an appropriate explanation of how to control these variables.
I have two
1.The volume of water for each experiment.(100ml)
2.size and mass of the fuel.

could you give me some others .please:(
this is urgent. please can you reply as soon as possible

[norman40]

Hi happyhammy,

An independent variable is something that you change in your experiment to get an observable response in a dependent variable. In your experiment the independent variable is the mass of your fuel blocks. Temperature is the dependent variable.

Controlled variables are things that must be held constant during your experiment to assure a fair test of the effect of the dependent variable on the independent variable. One controlled variable you mentioned is the volume of water. Some others that come to mind are the beaker size, beaker material (glass or metal), and type of thermometer used for temperature measurement. Changes to any of these items between tests of your dependent variables would change your results. You may be able to identify some additional controlled variables by thinking about things in your experimental procedures that could influence your results if they were not held constant.

I hope this helps. Please post again if you have more questions.

A. Norman