Iam giving a lot of points for a stupid question. i need honestly on this.
what kind of experiment would i do? that's what i don't understand. if you were a scientist, how would you test if cell phones cause health risks? what type of experiment might you design to figure out if you are frying your brain with your cell phone?

Its is a really tough one butu could carry out an experiment to show how cellphones harm ones eyes, thinking,body in some cases
u can compare between a person whom was busy with their phone close to their eye...harming their eyesight etc.
there are alot of cons...so make good use of that...
good luck than

You can do a control test on plants. buy some seedling plants ( like an herb plant but not full grown yet) and place the same amount of healthy in a room of at least 2 routers and placing the control group in another room that is a few rooms away  feeding them all the same food and water and in a controlled temperature for up to 14 weeks.
This test should show you the effects on a plant  of what wifi signals emitted from your cell phone ( which is radiation) has on the human body..

I hope this is what you are looking for.

True. the more you know, the better of you will be.