Opaque and Translucent Materials

A little girl woke up for school, cozy in her room. Outside it was very cold. She walked to the window to see if it had snowed, but the windows looked very strange. The winter night had covered them with icy frost. The morning light could shine in, but the girl couldn't really see out. Everything outside was only a blur. What made that happen? 

Translucent Materials
Opaque Materials
How Do We Know That?

Do you ever wonder why some objects let light through while others don't?

Translucent Materials
Sometimes light can shine through materials that aren't really clear. These materials are translucent. A translucent material allows light to pass through, but prevents the light from forming images. The object scatters the light when it enters. When the light is scattered, the image looses its sharpness.
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Opaque Materials
Light cannot shine through opaque materials at all. In fact, opaque materials absorb the light that shines on them. A little of the light is reflected back, though. Each object reflects some light waves of a certain color. Some objects reflect blue waves of light. These objects look blue to us. Other objects reflect yellow light. We see these objects as yellow. 
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How Do We Know That?
If you look around, you can see many translucent and opaque materials. Have you ever seen a door with white, frosted glass? Light can go right through this kind of glass. But if someone stands behind it, they'll look blurry. Frosted glass is opaque. So is tracing paper. Hold a piece up to the window. Light shines right through it! But you can't really see through it, right?

Opaque materials are things that have shadows. If a red apple is sitting in the sun, it will create a small shadow. This is because the red apple is opaque. The light cannot pass through it. The apple absorbs the sunlight and reflects red waves of light. This is why it looks red.  
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