# Interactions with Light

## Physical Science - Middle School

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Interactions With Light Reflection of Light A reflection can be sharp and clear, like the reflection from a mirror. This is called regular reflection. At other times the image is fuzzy, like the reflection in moving water. This is called diffuse reflection. diuse reection regular reection diuse reection regular reflection diffuse reflection Refraction of Light Light is refracted, or bent, when it passes from one substance to another. Light travels at about 300,000 km/s. If light travels from air to another material, such as water, the speed of light decreases. As light passes from air to water, instead of continuing in a straight line, the light ray is bent downward, or refracted. This causes an object in water to appear higher and the water to appear shallower than it really is. air speed of light = 300,000 km/s refraction glass air air index of refraction = n air water water Diffraction of Light Light travels in a straight line. Diffraction of light can only be seen when light passes through very small openings. The molecules that make up the atmosphere can sometimes act as these tiny openings. Sunlight behind a cloud is diffracted by the air molecules in the cloud, and produces a halo around the cloud. Polarized Light Light from most sources, such as the Sun or a lamp, travels outward in all directions. Light that travels in all directions is called incoherent light. Light that travels in only one direction is called coherent or polarized light. A special filter can be used to polarize light, which only allows light traveling in one direction to pass through. This is how polarizing sunglasses reduce the amount of light you see on a sunny day. A laser produces a special kind of polarized light that has high energy. incoherent light polarizing filter polarized light © Copyright NewPath Learning. All Rights Reserved. 94-4480 Visit www.newpathlearning.com for Online Learning Resources. In a regular reflection, parallel light rays hit a smooth surface and are all reflected at the same angle. While in a diffuse reflection the light rays are reflected in different angles. A material’s index of refraction, represented by n, is a measure of how much light bends when it enters that material. The higher the index of refraction the more light bends. air molecules
Description Interaction Reection Refraction Diraction Polarization Examples Pause and Review Fill in the table. Describe each interaction and give a real life example of each. © Copyright NewPath Learning. All Rights Reserved. 94-4480 Visit www.newpathlearning.com for Online Learning Resources. Interactions With Light