Colors of Objects

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Colors of Objects

This lesson aligns with NGSS PS4.B

Introduction

The captivating world of colors around us is a result of a fascinating interplay between light and matter. From the vibrant hues of a rainbow to the various shades of objects in our daily lives, the interaction of light with matter is a fundamental principle that explains the colorful world we observe. Light is a form of energy that travels in waves. These waves vary in wavelengths. The color that an object appears to be is determined by the wavelengths of light waves. In this article, we will delve into the science behind how light and matter come together to create the beautiful palette of colors we see everyday.

Colors of Objects

When we observe an object such as a blue pen, we are not seeing the pen itself. Instead, we are seeing the light that the pen reflects or emits. When light from a source strikes an object, it interacts with the surface of the object. The surface of the object is made up of tiny particles called molecules. The molecules on the surface of an object have a unique property – they can absorb and reflect certain wavelengths of light. The color of light is determined by the wavelength of the light wave.

When the light reaches your eyes after being reflected off an object or after being transmitted through an object, something amazing happens. It turns into tiny electrical messages that your brain reads as colors.

Colors of Opaque Objects

When white light interacts with a colored opaque object, some colors of light are absorbed and some are reflected. Only the light that is reflected reaches your eyes and is detected by your brain. Therefore, the colors of light that are reflected by an opaque object determine the color you perceive.

Imagine a green leaf under the Sun. The leaf appears green because its molecules absorb all the colors of light except green. Green light is reflected off the leaf's surface and into our eyes, creating the perception of a green leaf. Another example is mentioned below.

White and Black Colors

If green objects reflect green light and red objects reflect red light, what about the white color of a cow? White light is like a magic box that holds all the colors. When it touches white objects, like the cow's white hair —appears white because all the colors of light are reflected.

But then there's black, which is a bit mysterious. When light meets a black object, it absorbs all the colors and keeps them to itself. Therefore, we see it as black.

Colors of Transparent and Translucent Objects

Not all materials interact with light in the same way. The color of transparent and translucent objects is determined differently than the color of opaque objects. Transparent objects such as clear glass, allow light to pass through them without scattering the light. This is why you can see clearly through glass windows. On the other hand, translucent objects such as frosted glass or wax paper, scatter the light as it passes through, creating a blurred or diffused image.

However, some transparent objects are colored. When you look through colored transparent or translucent objects, you observe the color of light that was transmitted through the material. All the other colors were absorbed.

Summary

The color of light is determined by the wavelength of the light wave.
Red has the longest wavelength, while violet has the shortest wavelength. All other colors of light have wavelengths in between.
When white light interacts with a colored opaque object, some colors of light are absorbed and some are reflected. So, the colors of light that are reflected by an opaque object determine the color you perceive.
When light strikes on colored transparent or translucent objects, you observe the color of light that was transmitted through the material. All other colors were absorbed.

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