Here are some potential questions and hypotheses for a stem fair project on cell phone radiation:
Question: Does the distance between a cell phone and a person's head affect the level of radiation exposure?
Hypothesis: If a cell phone is held closer to a person's head, then the level of radiation exposure will be higher.
Question: Do different types of cell phone cases affect the level of radiation exposure?
Hypothesis: If a cell phone is covered by a case made of a certain material, then the level of radiation exposure will be lower.
Question: How does the amount of time a person spends on their cell phone affect their level of radiation exposure?
Hypothesis: If a person spends more time on their cell phone, then their level of radiation exposure will be higher.
It's important to note that these are just a few potential ideas, and you may want to come up with your own question and hypothesis based on your interests and the resources available to you. It's also important to conduct thorough research and use reliable sources to support your conclusions.