Examples of electromagnetic energy include gamma rays, X-rays, ultraviolet radiation, visible light and infrared radiation, as well as microwaves and radio waves. Electromagnetic energy is any self-propagating energy that has an electric and a magnetic field.
All these forms of electromagnetic energy do different things. Visible light makes objects discernible to the human eye and enables plants to carry out photosynthesis, infrared emits heat and X-rays enable us to image the internal structures of the human body for noninvasive medical examinations, to name only a few examples.
The different forms of electromagnetic energy all have some shared characteristics, however. First, all electromagnetic energy forms move in waves. The length of the wave actually determines the type of electromagnetism; extremely short waves are high-energy forms, such as gamma rays, while extremely long waves are low-energy forms, such as radio waves.
Second, all forms of electromagnetic energy can travel through the vacuum of space. Not all can reach the surface of the Earth, however. Our sun radiates all the forms of electromagnetic energy, for example, but the planet's atmosphere blocks some of them. A familiar example is ultraviolet radiation, which is mostly blocked by the ozone layer. Likewise, the infrared (heat) radiation emitted by Earth is trapped by the greenhouse gases of the planet's atmosphere.