Science Buddies: "Ask an Expert"

Hi my daughter is doing an experiment for the science fair. Her experiment is complete and she is finalizing her report. She is having trouble identifying her experiment independent variable, dependent variable and control group.
Her experiment is on the effects of freezing and thawing on rocks and which rock (igneous, sedimentary or metaphoric) would be the first to crack after being frozen in water and then thawed out.

Any help would be appreciated in identifying the experiment variables listed above

Hi there,

The project sounds great. We have a resource here on Science Buddies that would help your daughter with defining the variables for her project. https://www.sciencebuddies.org/science- ... bles.shtml

Take care!

Thank you. We read it but are still having a problem putting it in the context of the rocks and the freezing/thawing process. Could you please explain

Still looking for some help....any ideas from anyone please?

Hi! Sorry we didn't get back to your response very quickly.

In this case, the type of rock would be the independent variable, since it is the variable that is changing throughout the tests.
The dependent variable would be the cracking found in the rocks, since the amount of cracking DEPENDS on what type of rock is being tested.
Your controlled variable(s) are the variables kept constant throughout the experiment (such as the freezing and thawing temperatures).

Hope this helps! If you have any more questions, please ask.

This is very helpful. Thank you.