Final answer:
Heat waves or body heat are forms of infrared radiation, a type of electromagnetic radiation with longer wavelengths than visible light. This radiation is emitted by objects at certain temperatures, including our bodies, and can be felt as heat without requiring a medium to travel through.
Step-by-step explanation:
What we call heat waves or body heat is actually just infrared radiation. Both heat and light are forms of electromagnetic radiation. The key difference is in their wavelengths; heat, often emitted by objects as infrared radiation, has longer wavelengths than visible light. When materials absorb light of various wavelengths, that energy can be converted into heat, which we perceive as warmth. Heat transfer by radiation doesn't require a medium, as the electromagnetic waves are absorbed directly by our skin.
The sun emits a wide spectrum of electromagnetic radiation, including visible light and infrared radiation, which we feel as heat. Our bodies also emit infrared radiation due to our body temperature. This form of energy is a part of the electromagnetic spectrum, which also includes radio waves, microwaves, ultraviolet radiation, X-rays, and gamma rays. The perception of color in the human eye is limited to visible light, which makes up only a small fraction of the entire spectrum of electromagnetic radiation.