photons
Photons are tiny particles of light that are beyond our sight. All light is made of photons. Unlike electron and quarks, photons do not contain a mass, so they can travel at the speed of light. Photons act a lot like particles and in other ways like waves. It's not just sunlight that is made of photons, but a lot of other kinds of waves like radio waves, x-rays, and the ultraviolet rays that give you sunburns. The difference between light and waves depends on the wavelength. If a photon moves in short wavelengths, like x-rays or ultraviolet rays, then that photon has more energy. That's why you have to be careful how much x-ray radiation or UV rays you get, or you will get a sunburn. If the wavelength is longer, then that photon will have less energy, that's why it's not dangerous to stand in the way of radio signals and television signals. When photons hit atoms some of their energy can get the electrons in those atoms moving faster, which creates heat