Monday, December 5, 2011

What is the control variable for my science fair project?

For my science fair project Im growing crystals and and seeing the different rate of each crystal. All the materials are: 2 pencil, 2 paperclip, 2 cup, 2 tbsp of sugar, 2 tbsp of salt, 2 string, and 200ml of water per cup.


So what is the dependent Variable, independent variable, and controls?|||Everything you change on purpose is the `independent` variable. Everything that changes BECAUSE of that thing you changed is the `dependent` variable. And whatever you started with, that you didn`t change at all, is your control. Your control is what you make the changes to; it doesn`t matter where you start your control at.





So, if you added 1tbsp of salt and 1 tbsp of sugar to 50mL of water, and record the crystal sizes, this is your control. If you CHANGE it by adding 2tbsp of salt, and keep the same 1tbsp sugar and 50mL water, then the extra salt is your independent variable, because you yourself changed it, and the resulting crystal sizes are the dependent variable, because their size DEPENDS on how much salt and sugar you added.


You should have at least one control, but you can only change one thing at a time with it. So you can`t add more sugar AND more salt at the same time, because you`re putting too many variables, or unknowns, into the situation. You won`t know if the bigger crystal sizes are because of the salt, the sugar, or both mixed together.





Does this make sense? I hope so. Good luck with this, and have fun! (Science is awesome, after all. :))|||The independent variable in this experiment is the amount of sugar you use to make the crystal. The dependent variable is the varying size of the crystal as a result of using different amounts of sugar. A control would be a crystal created using the 'recommended' amount of sugar.|||okay your control would be your plain cup of water with no crystals in it, you haven't tampered with it.... your indpendent variable is the thing that you don't change and you dependent variable is the thing that you change in able to test your testable question

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