define radiation ?
Radiation is an energy that travels in the form of waves or high speed particles. Radiation may be electromagnetic (like light) or particulate (i.e., mass given off with the energy of motion). Gamma radiation and x rays are examples of electromagnetic radiation. Beta and alpha radiation are examples of particulate radiation.
Take two closed tin cans paint one black and the other white then pour equal amount of water in both of the cans. Now measure the water temperature in both case and note it down. Then leave both the tin cans out under the sunlight for 1 hour and then measure the temperature of water in both the tin cans. And note it down.
Find the difference between the reading of the two cans, you'd find the water temperature in the black coloured tin can would be more than that of the white.