Fluids
A golf ball has a density of 1 g/cm³. A volleyball has a density of 0.05 g/cm³. Which is denser?
Golf ball
Which travels through a vacuum: light, sound, or both?
light only
When we heat something, do particle lose or gain thermal energy?
Particles gain thermal energy
What imaginary line divides Earth into Northern and Southern Hemispheres?
Equator
Why do you see lightning before you hear thunder?
Light travels faster than sound
Why does ice float on water?
Ice is less dense than liquid water.
What is name for the bending of light because it changes speed when it passes through a medium?
Refraction
What is the difference between a thermal insulator and a thermal conductor?
Conductors: materials that are good at transferring energy
Insulators: materials that are not good at transferring energy
Why do we have seasons?
Earth's axis is tilted
You are floating in space. Which of these still works: flashlight, drum, both?
flashlight (only light)
You're climbing a mountain. Does air pressure increase or decrease as you go higher?
Decrease
Explain why you can see me (hi!) right now
Light reflects off of me and into your eyes
What are the three types of heat energy transfer?
radiation, conduction, and convection
What is the difference between mass and weight?
Mass is the amount of matter (stuff you're made of)
Weight is the force of gravity on that mass
Which statement is FALSE?
1. Energy can be destroyed.
2. Ice is less dense than liquid water.
3. Earth's axis is tilted.
1. Energy can be destroyed.
What is density?
Density is the mass of a certain volume of a substance
(how much matter is packed into a certain amount of space)
Describe the difference between: transparent, translucent, and opaque materials
Transparent: all light passes through.
Translucent: some light passes through
Opaque: no light passes through
Why does hot air rise?
Particles have more energy, so they expand (move apart) and become less dense
What is a light year?
A light year is the distance light travels in one year
A spacecraft lands on a planet where gravity is weaker than Earth's. What happens to the astronaut's mass and weight?
Mass stays the same.
Weight decreases.
A racing car designer wants less drag. Give one feature the car should have.
A streamlined/smooth shape (small front area)
In reflection, the angle of incidence is equal to what?
The angle of reflection
A lamp receives 200 J of electrical energy and produces only 50 J of useful light.
What is its efficiency?
25%
What are two differences between planets and stars?
Stars: Produces its own light; Doesn’t orbit a planet
Planets: Only reflects light; Orbits a star
Why does water's anomalous density change (when it becomes ice) beneficial to marine life?
water freezes from the top, leaving water under liquid, this protects the marine life underneath the surface