Science Buddies: "Ask an Expert"

Hi for a science assignment we are to develop a research question for an experiment that will be completed at a later date and I am after some advice as to whether or not I am on the right track. The question I have developed is " Does the temperature of water affect the way substances are dissolved?". I'm just wanting to know if I am on the right track with the variables, so far I have the independent variable as being the temperature of the water ( ice-cold, hot, room temperature) , the dependent variable being the rate in which each substance dissolves at, ( the substances I am using are : salt, sugar, bi-carb, asprin crushed, and gelatin) and the controlled variable being : the size of the container, the amount of water in each container, the weigh/amount of each substance, stirring of the substance. Am I on the right track? we are needing to have 5 controlled variables but so far I can only come up with 4, have I missed anything? and do you think this would be a fair test investigation?
I was originally going to go with only testing one substance like asprin as I'm not sure whether adding the other substances would be changing more than one independent variable at one time, would testing the other substances in different temperatures of water be adding more independent variables?
I appreciate any feedback thank you .

Hi for a science assignment we are to develop a research question for an experiment that will be completed at a later date and I am after some advice as to whether or not I am on the right track. The question I have developed is " Does the temperature of water affect the way substances are dissolved?". I'm just wanting to know if I am on the right track with the variables, so far I have the independent variable as being the temperature of the water ( ice-cold, hot, room temperature) , the dependent variable being the rate in which each substance dissolves at, ( the substances I am using are : salt, sugar, bi-carb, asprin crushed, and gelatin) and the controlled variable being : the size of the container, the amount of water in each container, the weigh/amount of each substance, stirring of the substance. Am I on the right track? we are needing to have 5 controlled variables but so far I can only come up with 4, have I missed anything? and do you think this would be a fair test investigation?

This all looks correct to me.

I was originally going to go with only testing one substance like asprin as I'm not sure whether adding the other substances would be changing more than one independent variable at one time, would testing the other substances in different temperatures of water be adding more independent variables?
I appreciate any feedback thank you .

For each substance, the temperature of the water is the independent variable. You are correct that changing substances is a complication. Now you are doing multiple comparisons. 1: for any 1 substance does temperature affect time to dissolve. 2: Does this behavior vary among substances. When you are doing the second comparison in effect the substance is the independent variable. All the other properties are the controlled variables, and the relationship between temperature and time to dissolving is the dependent variable. I think you have everything right.


Cheers,
Colin