Grade 4 Science
Give an example of a light emitter and an example of a light reflector
Examples of Light Emitters The sun, stars, candles and light bulbs
Examples of Light Reflectors The moon, safety reflecting vests, and minerals
True or False
Examples of artificial lights include: candles
True
Is the sun an example of a natural or artificial light source?
Natural
What is an example of an artificial light source?
Answers with vary
What is Echolocation
a physiological process for locating distant or invisible objects (such as prey) by sound waves reflected back to the emitter (such as a bat) from the objects
We learned that heat is also called thermal energy. It is the movement of tiny particles called molecules.
Now is true or false that "The hotter a solid, liquid, or gas is, the slower the molecules move!"
An object that lets some (but not all) light pass through is...
Translucent
An object may appear bent in water due to...
Refraction
T or F
The soothing noise of water lapping on the beach is an example of an artificial sound
FALSE
T or F
Sound is a form of energy
True
An object that appears blue ___________ blue light and ___________ other colours of light.
reflects, absorbs
Different wavelengths of light result in...
Different colours (some are invisible to the eye)
Sound comes from .............that create .............. .
vibrations
sound waves
an sound travel in a vacuum? Why or why not?
No because there is no matter for the sound waves to travel along
The moon and a safety vest are similar sources of light because they both...
Reflect light from other light sources
It is harder to see the stars in the city because...
There are a lot of artificial light sources (light pollution)
Sound travels ....... times faster through water than through air
4 times
Sound travels at a speed of ...............km per H
1,230 km
Glasses, contact lenses, cameras
Why does an arrow appear backwards when viewed through water? (This requires more than a one-word answer)
The light moves at different speeds through the glass, water, and air.