What passes through glass:
* Visible light: This is the portion of the electromagnetic spectrum we can see. Glass is transparent to visible light, allowing us to see through it.
* Some near-infrared (NIR) radiation: This is heat radiation. Some NIR wavelengths can pass through glass, which is why greenhouses use glass to trap heat.
* Some ultraviolet (UV) radiation: A small amount of UV radiation can pass through glass, but most is absorbed. This is why you can still get a sunburn through a window.
What doesn't pass through glass:
* Far-infrared (FIR) radiation: These longer wavelengths are mostly absorbed by glass, which is why glass is a good insulator.
* Microwaves: These waves are blocked by glass, which is why you can't use your microwave with the door open.
* Radio waves: Glass is generally opaque to radio waves, though some wavelengths can pass through depending on the type of glass and thickness.
* X-rays and gamma rays: These very high-energy waves are completely absorbed by glass.
Why?
The ability of electromagnetic waves to pass through glass depends on their frequency and wavelength. Here's how it works:
* Higher frequency/shorter wavelength: The more energy a wave has, the more likely it is to interact with the atoms in the glass, leading to absorption. This is why X-rays and gamma rays don't pass through.
* Lower frequency/longer wavelength: Waves with lower energy are less likely to interact with the glass atoms and can pass through. This is why visible light and some infrared radiation can get through.
So, while glass isn't completely opaque to all electromagnetic waves, it does have a selective permeability based on the energy level of the waves.
