Lesson Plan - Get It!
What is "light"? Does all light originate from the sun? Light is pretty heavy stuff to think about, isn't it?
Shine a flashlight at a solid surface.
Look at the light that is projected. Describe what you see to your teacher or parent. Then, discuss what exactly you think light is and where it comes from.
Light is essential to human life! You wouldn't be able to do much if you lived in complete darkness, but light is so much more than just the opposite of the dark.
Simply stated, light is energy. Light can be a natural energy source, such as the sun, or it can be an artificial energy source, such as the energy produced by the battery in a flashlight.
Energy travels in waves. The lights and colors you see are your brain's perception of energy. If you were able to see each wave of energy that came from the sun or a flashlight, you would see hundreds or thousands of waves.
Since energy travels in waves, light has properties of a wave. You will learn more about light waves in the next of the Related Lessons, found in the right-hand sidebar.
Light also has properties of a particle. Scientists call these particles photons, light particles made of electromagnetic energy. To learn more about photons, read Photon (Encyclopædia Britannica, Inc.). It can be difficult to explain what a photon is. Create your own definition for photon, based on the passage you read. Share with, and explain your definition to, your teacher or parent.
All scientists agree that light is energy, but many still disagree about whether light is a wave or a particle.
Continue on to the Got It? section to learn more about this scientific debate.