Microwaves propagate through space by means of electromagnetic waves. Electromagnetic waves are a combination of electric and magnetic fields that oscillate perpendicular to each other and travel through space at the speed of light.
In the case of microwaves, they fall within the electromagnetic spectrum with wavelengths ranging from approximately 1 millimeter to 1 meter. These waves are generated by a microwave source, such as the magnetron in a microwave oven or an antenna in a communication device.
Once generated, microwaves propagate through space in a straight line until they encounter an obstacle or are absorbed by a material. Unlike visible light, microwaves can pass through certain materials, such as glass, plastic, and ceramics, but are absorbed by others, like metal.
When microwaves encounter an object, their behavior depends on the size and nature of the object relative to the wavelength of the microwaves. If the object is much larger than the wavelength, it will typically reflect or scatter the microwaves. This is why you can see the reflection of microwave signals off surfaces in your everyday life, such as metal objects or the walls of a microwave oven.
On the other hand, if the object is of comparable size to the wavelength, it can absorb the microwaves, converting their energy into heat. This absorption property is the principle behind microwave ovens. The microwaves are absorbed by the water molecules in food, causing them to vibrate and generate heat, which cooks the food.
In summary, microwaves propagate as electromagnetic waves through space, traveling in straight lines until they encounter objects that can reflect or absorb them, depending on the nature and size of the objects involved.