Science Buddies: "Ask an Expert"

In the solar powered bristle bot experiment given on this site, is using the battery power the control and the 3 different weather conditions are the independent variable? Or are the 3 weather conditions considered separate tests and the independent variable is the power source?

Also, fossil fuels are focused on in the background research. Are standard batteries considered a fossil fuel? From my research I think they usually use electrolytes and there is a chemical reaction that produces the energy, but I am having a hard time understanding if they somehow fall into the category of fossil fuels? Or are they just used as a control in this experiment and the experiment is not about comparing solar power to fossil fuels?

Thank you for your help.

Hi dawefam,
You are correct. The battery power is the control and 3 weather condition is indeed the independent variables. (The independent variable is the variable that you, the scientist, is changing to see how the dependent variable response. In this experiment, the dependent variable is the speed that you are recording.) https://www.sciencebuddies.org/science- ... /variables

In regards to your question about whether battery is consider a fossil fuel, the answer is NO. Like you had found in your research, batteries are typically consisting of chemicals and is not like Fossil fuel, which comes from buried / dead organism. https://en.wikipedia.org/wiki/Fossil_fuel

Good Luck and please post again if you have any other questions!
Willey

Thank you SO much for your response! This is so helpful!