The Power of Light
What is the definition of energy?
The ability to do work. (Energy also causes objects and substances to change and move).
If you are outside on a hot, sunny day, should you wear a dark shirt or a lighter-colored shirt to stay cool? Why?
A lighter-colored shirt, because it absorbs less of the Sun's light. (Darker shirts absorb more light, causing them to become warmer).
Give an example of an object that emits light energy.
Ex: flashlight, fire, the Sun
A straw sitting in a clear glass of water looks like it is broken or split in half where it enters the water. Is the light being reflected, bent, or absorbed?
Bent
How does light energy move through space until it hits an object or substance?
In a straight line.
What property of light occurs when it hits a shiny surface, like metal or a mirror, causing the light energy to bounce off?
Reflection.
This term describes light "bouncing off" a shiny surface like a mirror or metal.
Reflection
You look into a calm, still lake and can see the trees and clouds perfectly mirrored on the surface of the water. Is the light being reflected, bent, or absorbed?
Reflected
What are the three things that can happen to light when it comes into contact with the surface of an object or substance?
It will be absorbed (taken in), reflected (bounced off), or it will refract (bend).
What is created when light moving in a straight line hits a solid object, causing a lack of light behind that object?
A shadow.
This vocabulary word means that light is "taken in" by an object, such as a dark shirt absorbing the Sun's rays.
Absorption
You leave a black asphalt driveway exposed to the bright sunlight all afternoon. By 2 p.m., the ground is scorching hot to the touch. Is the light being reflected, bent, or absorbed?
Absorbed
If you are looking at a red apple, which color of light is bouncing off the apple into your eyes, and what happens to all the other colors?
Red light is reflected into your eyes, and all the other colors are absorbed by the apple.
Light energy and heat (thermal) energy often come from the same source. What is one example of this?
Light bulb or fire
When light travels through a substance like water and slows down, it appears to bend. What is the scientific term for the bending of light?
Refraction
A scientist shines a flashlight through a glass prism, and a beautiful rainbow of colors comes out the other side. Is the light being reflected, bent, or absorbed?
Bent
Why does light energy bend when it travels through a substance like water?
Because it is traveling at a speed less than it would through the air.
Light that includes a perfect mix of all the colors of the rainbow (red, orange, yellow, green, blue, indigo, and violet) is known by what name?
White Light
A shadow is actually caused by a combination of two things: the lack of light directly behind a solid object, and what happening to the light that doesn't hit the object?
It continues to move past the object.
You look at the back of a clean, shiny metal spoon and can see your face bouncing right back at you. Is the light being reflected, bent, or absorbed?
Reflected