If light hits an object and doesn't bounce off or go through it, then it must be absorbed or soaked up. If you’ve ever headed for the shade to cool down on a bright hot day, you already know that absorbed light energy becomes heat energy.
Watch this animation to find out what happens to an object when it absorbs all of that light energy
Stop the animation at any time, watch it again, or read the transcript.
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Light is energy-- electromagnetic energy to be exact-- that travels in waves. Whether it is visible or invisible to our eyes, light energy is interacting with the objects and mediums all around us: it is being reflected, refracted, transmitted and absorbed.
And that last one- absorption- is particularly interesting because as that light energy absorbs into the object or medium, it transfers its energy and the object or medium heats up. It’s why the sun on your skin feels warm, why that heat lamp keeps your pet lizard happy, and why microwaves heat your food; electromagnetic waves are absorbed and transfer their energy.
But the amount of energy transfer depends on three main things-- how intense or bright your light is, how long that light interacts with the object, and how many wavelengths of the light your object is absorbing. The brighter the light, the longer the time and darker the object or medium, the more light energy will be absorbed and the hotter things get.
So that black shirt on a sunny day while waiting for a ride on that hot new roller coaster? Probably not the best choice- and all because of light energy and absorption.
Answer the following two questions in the note box, below. (Click SAVE when you have finished. To see your saved or submitted work again, click MY WORK at the top of the page.)
1) What is absorption? Use a full sentence to describe it.
2) The amount of energy transferred when light is absorbed depends on three main things. List two of them here.