Science - Light Flashcards
What is light?
Light is a type of energy that allows us to see.
What is a natural source of light?
A natural source of light is light that happens in nature. It happens naturally.
Name some examples of natural sources of light.
- lightning
- forest fires
- bioluminescence (things that are alive and make their own light) (fireflies, anglerfish, some jellyfish, some mushrooms)
- the sun and other stars
What is an artificial source of light?
An artificial source of light is one that is man-made.
What are some examples of artificial sources of light?
- lightbulbs
- fireworks
- TV screens and devices
- streetlights and stoplights
- candles
- glowsticks
When most sources of light produce light energy, what other type of energy do they often produce?
Most sources of light also produce heat energy.
Name a source of light that does not produce heat.
glowsticks, anglerfish, fireflies
Name the colours of light that are contained in white light.
red, orange, yellow, green, blue, indigo, purple
What is reflection?
Reflection is when light gets bounced off an object it hits.
What is absorption?
When light gets absorbed (taken in) by an object it hits.
What is refraction?
Refraction is when light gets slowed down and bent.
What causes light to get refracted (bent)?
When light travels from one material to another (like from air to water) it slows down. This causes the light to change direction. That’s refraction.
How do rainbows appear?
Sunlight passes though water droplets in the sky. The water droplets refract (bend) the beams of light, and split the white light into its separate colours.
What type of object can we use to refract light and make a small rainbow in our house?
A prism. A prism is a piece of glass or plastic that has straight sides and can refract (bend) light into all the colours.
What are the two main types of lenses?
Convex lenses.
Concave lenses.
Which lens has sides that curve inward?
Concave
Which lens has sides that curve outward?
Convex
Which type of lens do we have in our eyes?
Convex lenses are in our eyes.
When beams of light pass though a convex lens, how does it change their direction?
Beams of light passing though a convex lens get bent toward each other.
When beams of light go though a convex lens and get bent toward each other, what do we call the spot where those beams meet and cross each other?
The beams meet at the focal point.
Why does a pencil, or any kind of stick, look bent when it is sitting in a glass of water?
The light is getting refracted. The light goes from the air, into the water in the glass, and slows down and bends. That means the light coming to our eyes from the submerged part of the pencil is coming in a slightly different direction.
Name some tools and inventions that use light, refraction, or optics in some way.
- magnifying glasses - make small things look bigger.
- microscopes - make tiny things look bigger.
- telescopes - make distant things look closer
- Fiber optics - passes light energy through fiber cables until the light comes out the end of the cable.
- Laser security systems - beams of light trigger an alarm if the beam is blocked by a person stepping through it.
- glasses - help people see clearly.
What do we call an object that allows light to pass right through it?
transparent
What do we call an object that allows some light to pass through it?
translucent
What do we call an object that lets no light pass through it?
opaque
