Biology: What is a controlled variable,dependant,etc...?

OKay, we have this assignment and I just want some help cause I am confused. Its 9th grade project: Here it goes...





We have to design an experiment about Lung capacity and I already know what I want to do but the only problem is the critteria says:





'; choose one controlled relevant variables and two test variables';





what do those words mean?





Thank youBiology: What is a controlled variable,dependant,etc...?
Ask your teacher - it's what they're paid for.





But seriously.





In this case, a controlled variable is something that remains stable and unchanging. You haven't altered it in any way, and you will be comparing the test variables against it.





The test variables here would be two different ways you could show different lung capacities (that's just an example I came up with).





The bottom line is: Test variables are the ones you change or experiment with, while the controlled variable is the 'normal' one that you compare them with.





Hope this helps, but please ask your teacher to clarify it - that's what he/she is there for!!





Good luck :)