A gamma ray is one of the most poweful and destructive forces in the electromagnetic range. Gamma rays are emmited during a supernova, type IA or IIA, and are constantly being produced by white holes, the "theoretical" other end of a black hole. If one was to look at an animation of a supernova they would see a bright beam of light baing spewed from it, this is a gamma ray. A GRB reffers to the gamma rays being emitted or stricking earth. If this where to happen, the atmoshpere would vaporize and all living things, or almost, would die of 1,000 time the lethal dose of radiation. If going to ISEF, where i have competed, you will need a concrete basis for your project explainng what they are where they come from, effects of them, and on and on. Research supernovae first, and then go on from there, Also watch the UNIVERSE, my favorite show.