Light Sources
Light Sources
This lesson aligns with NGSS PS4.B
Introduction
While visible light occupies a small portion of the electromagnetic spectrum, its impact on our lives is profound. The visible light emitted by the sun serves as the primary energy source for plants, enabling their growth and reproductive processes. Without plants forming the foundation of the food chain, the existence of numerous other life forms would be severely compromised. Additionally, the significance of visible light becomes evident in our ability to see the world around us. In the absence of sources emitting visible light, our eyes would be useless. In this article, we will learn about natural light sources, artificial light sources, and how light is produced.
What are Light Sources?
Light is the brightness that lets you perceive things around you. When you are looking at a television set in a bright room, you see not only the image displayed on the screen but also the cabinet housing the television. However, when viewing the same television in the dark, only the image on the screen becomes apparent.
The difference is that the screen functions as a light source, while the surrounding cabinet does not. The visibility of a light source in darkness results from its capability to emit light directly into your eyes. Examples of such light sources include flames, light bulbs, fireflies, and the sun. In scientific terms, objects capable of producing visible light are described as luminous.
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Most of the objects in your surroundings are not light sources. But you are still able to see them because they interact with light emitted by a light source. This light reflects off the objects and then travels to your eyes. In scientific terms, a visible object that is not a light source is being illuminated.
Natural Light Sources
The most prominent natural light source is the sun. The sun emits a wide range of light, including visible light that allows us to see. It is the primary source of natural light on Earth, providing energy and life to our planet. The sun's light is made up of various colors, which we can see when it passes through a prism, creating a beautiful rainbow of colors. This phenomenon is known as dispersion.
Natural light sources also include celestial bodies like stars, the moon, and even lightning during thunderstorms.
Artificial Light Sources
Artificial light is human-made, and designed to provide illumination in various settings. These light sources have evolved, becoming more efficient, diverse, and environmentally friendly. Incandescent light, fluorescent light, Neon light, and vapor light are artificial light sources.
Incandescent Light
One of the most well-known artificial light sources is the incandescent bulb. This was one of the earliest forms of electric lighting. It was invented by Thomas Edison in the late 19th century. These bulbs have been widely used for decades, but they are not very energy-efficient.
Fluorescent Light
Fluorescent lights are more energy-efficient than incandescent bulbs and are commonly used in offices, schools, and homes.
LED Lights
Light Emitting Diodes (LEDs) have revolutionized the world of artificial lighting. LEDs are incredibly energy-efficient, durable, and versatile. They work by passing an electrical current through a semiconductor, which emits light. LEDs are now used in a wide range of applications, from household lighting to traffic signals and electronic devices.
Halogen Lamps
Halogen lamps are a type of incandescent lamp that uses halogen gas to increase efficiency and lifespan. They produce a bright, white light and are often used in spotlights, car headlights, and outdoor lighting.
Production of Light
Light sources are responsible for emitting light in many ways. For instance, one such method involves heating a piece of metal to a high temperature, causing it to emit a visible red glow. Light can be generated chemically, like the light produced by a firefly. Moreover, the passage of an electric current through specific gases can also result in the production of light.
Summary
- Light is the brightness that lets you perceive things around you. Examples of light sources include flames, light bulbs, fireflies, and the sun.
- The objects capable of producing visible light are described as luminous, while a visible object that is not a light source is being illuminated.
- The most prominent natural light source is the sun.
- Artificial light is human-made, and designed to provide illumination in various settings. Incandescent light, fluorescent light, Neon light, and vapor light are artificial light sources
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