Light Energy By: Genevieve Rickey 5th Grade Mrs. Branin 2016
Everyone has probably turned on a light before, but have you ever thought about what light is? Light is a form of energy that is reflected from some objects. Light is not a form of matter. Light is a mean of transferring energy between points. Light is produced by three different types of energy. They are nuclear energy, chemical energy, and electrical energy. The sun produces light from nuclear energy. A burner flame produces light from chemical energy. An electric light bulb produces light from electrical energy. Heat is involved in all three cases. What is Light?
How does Light Travel? Know that you know what light is, are you wondering how it travels? It does not need matter to travel. Light can travel in straight lines or not in straight lines. If there is a shadow behind an object that suggests that that the light traveled in a straight line. As long as the light travels in one type of matter it will travel in a straight line. A beam of straight light is called a light ray. Some scientists think that light travels as tiny bundles of energy called photons.
Concave Mirrors A concave mirror curves out on the shiny side. They can form many different types of images, depending on the position of the object in relation to the mirror. Images formed by a concave mirror depend on how far the object is from the mirror. When objects are very close, they image in the mirror is enlarged and right-side-up. The mirror produces upside down images when the object is farther away. As the object gets farther and farther away from the mirror, the image remains upside down but gets smaller.
Convex Mirrors A convex mirror is curved out on the shiny side. Convex mirrors always form smaller, upright images. Convex mirrors are used as side rearview mirrors in cars. These mirrors give a wide angle view. Cars in mirrors seem to be farther away than they really are. Convex mirrors can also be uses in stores as security mirrors.
What is polarization? In our daily lives, we use many products that control the light. Polarization allows light vibrations to pass through in only one direction. Light travels in waves. Normally these waves vibrate in all directions. However, light can be polarized by some materials. Sunglasses use polarization. The polarization materials in sunglasses let through only the light that is vibrating up and down. This blocks glare and all other kinds of light that vibrates sideways. Because of this, we can see clearly on sunny days when we wear sunglasses.
Opaque materials completely block light from passing through. A stuffed animal is an example of an opaque material. No light can pass through the stuffed animal. Opaque
A transparent material allows light to pass through with almost no disturbance. Transparent materials may or may not color the light. You can always objects clearly through these materials. An example of a transparent material is a window. When you look through a window, you can always see the beautiful nature on the other side. Transparent
Translucent materials allow only part of the light to pass through, while also bouncing it in many new directions. Since translucent materials give only a blurry view, they are often used in shower doors. They let some light in, but they provide privacy. Translucent
Refraction is the bending of light rays as they pass from one substance into another. Refraction causes the light to to turn in a new direction. When you put a pencil into a clear glass of water, it may look bent. The illusion is caused when light rays from the lower part of the pencil change directions as they go from water to air. Refraction
Concave Lenses Concave lenses form images by refracting light rays apart. These images are always right side up and look smaller than the original object. These lenses curve inward. If you are nearsighted, you will need a concave lens. The lens will allow the image to fall on the retina.
Convex Lenses Convex lenses form images by refracting light rays together. The size and position of the image depends on how far the object is from the lens. These lenses curve outward. People who are farsighted need convex lenses to see. They allow the image to fall on the retina.
Light Passing Through Matter Light usually changes its direction when it passes from one substance into another. Light travels in waves, and these waves can be distributed or bent when the travel past the edge of a thin object. They also do this when they flow through a very narrow opening.
A prism is a triangular piece of cut and polished glass. When white light hits the prism, it simply spread the colors out by refracting each one at a different angle. The result is the spectrum. The spectrum is another word for rainbow. White light is really made up of all of the colors in the spectrum. If you shine the rainbow unto another prism, the result would be white light. Have you ever seen a rainbow in the sky? In this process, the raindrops act as the prism and they sun acts as the white light. Prisms
Electromagnetic Spectrum The electromagnetic spectrum is all of the wavelengths of visible and invisible light in order from short to long. The wavelength is measured from crest to crest. The colors of light have all different wave lengths. Red has the longest while violet has the shortest. Radio waves, Microwaves, and infrared light all have wavelengths longer than red. These waves are not seen. Ultraviolet light, X rays, and Gamma rays aren't seen either because their waves are shorter than violet light.
Summary Light is not matter. It is a form of energy that is reflected by some objects. When color is reflected, and object will look that color. Looking at different mirrors and looking through different lenses can change an image. The electromagnetic spectrum shows us visible and invisible light. Who would think turning on a light switch has so much science behind it.
I hope you enjoyed learning about light energy!