Distinguish among materials that are opaque, translucent, and transparent in terms of their appearance and light transmittance.

When you're in a room with the curtains drawn during the day, very little light seeps in. This is because the material of the curtains is most likely opaque, meaning it doesn't allow light to pass through. Opaque materials are essential in everyday life as they provide privacy and protection from light. Examples of opaque substances include materials like metals, such as steel and copper, which reflect light rather than letting it pass through. Similarly, wood is an opaque material; when you stand behind a wooden door, you can't see through to the other side.
Opaque materials play a crucial role in construction and design for providing structural integrity and controlling light within spaces. Their zero to minimal transmittance means that they either absorb light, which converts to heat, or they reflect light, appearing solid and impenetrable to the human eye. For instance, think of a metal teapot or a brick wall; you cannot see the contents of the teapot or what is on the other side of the wall because these materials do not allow light to transmit through them.

Imagine you're holding a sheet of wax paper up to the sun. You can see light passing through, but you can't quite make out the details of objects on the other side. This is characteristic of translucent materials. They sit in between opaque and transparent materials in terms of light transmittance. These materials allow light to pass through but scatter the rays so that images seen through them are not sharp.
Examples of translucent objects include frosted glass and certain plastics. When light encounters these materials, it is diffused, creating a soft glow that partially masks what lies beyond. Frosted glass, commonly used in bathroom windows and shower doors, provides privacy while still letting in light. This property of translucent materials is particularly helpful for creating ambiance or mood lighting. Another everyday use is in lamp shades which allow light to spread uniformly without revealing the bare bulb inside.

Have you ever looked through a window and admired the view? The glass in that window is transparent, providing a clear path for light to travel through, allowing you to see the outside world without obstruction. Transparent materials, such as clear glass, water, and some plastics, enable us to view objects with very little distortion because they have high light transmittance.
In your home, windows are made from transparent materials to offer visibility and light. Optics, such as eyeglasses and microscopes, also depend on the transparency of their lenses to function correctly. The clarity of these materials is crucial in numerous applications, from the screens on our smartphones and computers to the windshields of our cars, emphasizing the value of clear and undistorted vision. Clean air is another transparent material, so invisible that we may not even think of it as a 'material,' yet it allows us to see across vast distances.