Visible Light and Ultraviolet Light

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Visible Light and Ultraviolet Light

This lesson aligns with NGSS PS4.B

Introduction

Visible light is a type of electromagnetic radiation that is visible to the human eye. We can see the visible light as a rainbow color where each color consists of a different wavelength. When we observe our surroundings, we can see objects because of the reflection of light off them. However, when a bee sees the same objects, it would see them differently. It is because these bees can see the light which is invisible to the human eye. This type of light is known as ultraviolet light. In this article, we will learn about visible light and ultraviolet light, their properties, and their applications in our lives.

Visible Light

Visible light lies within the electromagnetic spectrum that is visible to the human eye. It consists of a spectrum of colors, ranging from red, orange, yellow, green, blue, indigo, and violet. These colors can be seen when light passes through the prism, creating the well-known rainbow effect.

Red light has the longest wavelength and violet light has the shortest wavelength among all other colors. Therefore, violet light carries more energy due to its shorter wavelength.

The electromagnetic spectrum is a scale that categorizes various forms of electromagnetic radiation based on their wavelengths and frequencies. Visible light occupies a small portion of this spectrum, sandwiched between shorter-wavelength ultraviolet (UV) light and longer-wavelength infrared light.

Colors of Light

The range of colors is known as the visible spectrum. To memorize these colors, you can use the mnemonic “Roy G Biv” which stands for red, orange, yellow, green, blue, indigo, and violet. Combining all those colors results in which we see the light as white light. Examples of sources emitting white light include sunlight, incandescent light bulbs, and fluorescent light bulbs.

Ultraviolet Light

Ultraviolet light is a form of electromagnetic wave originating from the sun. Compared to visible light, it possesses shorter wavelengths and higher frequencies than visible light, resulting in a higher energy level. This greater amount of energy impacts us in both positive and negative ways.

One of the most interesting aspects of ultraviolet light is how it is perceived by different creatures. Bees, for example, have a unique ability to see into the UV spectrum. Certain flowers have distinct patterns or markings on their petals that are invisible to humans but visible to bees under ultraviolet light.

Positive Effects

In a beneficial context, ultraviolet waves are generated artificially by ultraviolet lamps to serve the purpose of killing bacteria on both food and surgical instruments.

Moreover, controlled exposure to ultraviolet light provides an advantage to our bodies. When our skin is exposed to ultraviolet light, it triggers the production of vitamin D, a crucial substance necessary for calcium absorption by the intestines. Adequate calcium absorption is vital for maintaining strong teeth and bones.

Negative Effects

On the negative side, excessive exposure to ultraviolet light can lead to several adverse effects on our health and appearance, including sunburn, skin cancer, eye damage, wrinkles, and premature aging of the skin. Although much of the sun's ultraviolet light is filtered out by the Earth's atmosphere, it is essential to protect ourselves from the remaining ultraviolet rays that reach the surface.

To safeguard against harmful ultraviolet light, it is crucial to take precautionary measures. Utilizing sunscreen with a high Sun Protection Factor (SPF) and wearing sunglasses that effectively block ultraviolet light can significantly reduce the risk of UV-related health issues. It is vital to recognize that ultraviolet light can penetrate through clouds, so even on overcast days, adequate protection is still necessary.

Summary

Visible light lies within the electromagnetic spectrum that is visible to the human eye.
It consists of a spectrum of colors, ranging from red, orange, yellow, green, blue, indigo, and violet. The range of colors is known as the visible spectrum.
Ultraviolet light is a form of electromagnetic wave originating from the sun.
Compared to visible light, it possesses shorter wavelengths and higher frequencies than visible light.
Artificial Ultraviolet waves are used to kill bacteria on both food and surgical instruments.

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