Light is energy that allows us to see. In a vacuum, such as space, light rays travel in a ______________________ path and at the same speed. On Earth, however, light travels through different types of ______________________ . This affects both the speed and direction. When light rays change speed and direction, this is called ______________________ .
Refraction happens all the time and all around us. Refraction is most easily observed when we place an object like a straw or pencil in water. The object appears bent or enlarged. The path of light is creating an ______________________ . Remove the item from the water and you can see that it is not changed.
The speed at which light travels changes as it moves through ______________________ solids, liquids, and gases. Light will always take the fastest path it can between two places even if that path is not straight. Light travels faster through gas than it does liquids and solids.
A ______________________ is a tool used to separate white light into a spectrum of colors. White light refracts when it passes through a prism, causing the light to split apart. The light travels through the air, through the solid glass, and back through the air again into our eyes.
Many technologies today rely on the refraction of light to work. Lenses in glasses, some telescopes, and microscopes are all examples. ______________________ use a small curved lens or sphere to refract light and enlarge the image to see more than what the naked eye is capable of.