Matter
A chef is using a metal spoon and a plastic spoon to stir hot soup. Which spoon will feel hot to the touch first, and why?
a) The metal spoon, because it is a conductor.
b) The plastic spoon, because it is a conductor.
c) The metal spoon, because it is an insulator.
d) The plastic spoon, because it is an insulator.
a) The metal spoon, because it is a conductor.
Why?
Why is the copper part of an electrical wire almost always covered in plastic or rubber?
a) To help the electricity flow faster through the copper.
b) To make the wire more flexible.
c) To act as an insulator and prevent electric shock.
d) To keep the copper wire from rusting.
c) To act as an insulator and prevent electric shock.
Objects that let some light through but blur the image are __________. Objects that block all light are __________.
a) Opaque; Transparent
b) Transparent; Translucent
c) Translucent; Opaque
d) Reflective; Refractive
c) Translucent; Opaque
On the Moon, a feather and hammer fall at the same rate. What force pulls them down?
a) Air Resistance
b) Magnetism
c) Friction
d) Gravity
d) Gravity
When you pluck a guitar string to produce sound, what is the string doing physically?
a) Melting
b) Vibrating
c) Heating up
d) Changing color
b) Vibrating
A grape sinks in soda, while popcorn floats. Compare their densities.
a) The grape is denser than the soda; the popcorn is less dense than the soda.
b) The grape is less dense than the soda; the popcorn is denser than the soda.
c) Both the grape and the popcorn are denser than the soda.
d) The soda is denser than both the grape and the popcorn.
a) The grape is denser than the soda; the popcorn is less dense than the soda.
In a parallel circuit with three bulbs, one burns out. What happens to the others?
a) Only one bulb stays lit while the other goes out.
b) They both go out because the circuit is broken.
c) They get much brighter because they have more energy.
d) They stay lit because there are still complete paths for electricity.
d) They stay lit because there are still complete paths for electricity.
How does the size of a shadow change when you move a flashlight closer to an object?
a) The shadow gets larger.
b) The shadow gets smaller.
c) The shadow stays exactly the same size.
d) The shadow disappears completely.
a) The shadow gets larger.
Student A pushes a box with 10N to the right. Student B pushes the same box with 10N to the left. Describe the motion of the box.
a) The box moves slowly to the right.
b) The forces are balanced, so the box does not move.
c) The box moves quickly to the left.
d) The box will spin in circles.
b) The forces are balanced, so the box does not move.
A ball sits at the top of a hill. As it rolls down, its __________ energy transforms into __________ energy.
a) Thermal; Sound
b) Kinetic; Potential
c) Potential; Kinetic
d) Electrical; Light
c) Potential; Kinetic
You have a mixture of sand and salt. Describe the process you would use to separate the salt from the sand
First, add water to the mixture and stir so the salt dissolves. Next, pour the mixture through a filter; the sand will stay in the filter while the salt water passes through. Finally, evaporate or boil the water, which will leave the solid salt behind.
Identify two objects in your classroom that act as insulators and two that act as conductors.
(Answers will vary)
A prism separates white light into a rainbow of colors. Is this caused by reflection or refraction? Explain.
Refraction. The prism bends the light waves as they pass through it. Different colors of light bend at slightly different angles, causing them to separate.
Why do sneakers have rubber soles with deep grooves (tread) instead of smooth, hard plastic soles?
To increase friction between the shoe and the ground, which provides better grip and prevents slipping.
You feel the warmth of a campfire on your face even though you aren’t touching the flames. How is the heat energy reaching you?
By radiation.
Material A has a mass of 50g and a volume of 10L . Material B has a mass of 50g and a volume of 25L. Which material is more dense?
Density= mass ÷ volume
Material A is more dense than Material B because it has a higher mass per unit volume (5g/L} > 2 g/L).
A student builds a circuit that turns a motor and lights a bulb. What two types of energy is the electrical energy being transformed into?
Mechanical (kinetic/motion) energy (from the motor) and Light/Radiant energy (from the bulb).
Note: Heat/Thermal energy is also an acceptable addition.
Why does a straw or a spoon look “broken” or shifted when you place it in a glass of water?
This is caused by refraction. Light travels at different speeds through air and water. As the light passes from the water to the air, it bends, distorting the image of the straw.
A cyclist is pedaling at a constant speed. Suddenly, they start pedaling much harder. What happens to the balance of forces acting on the bike?
The forces become unbalanced. The applied force forward becomes greater than the opposing forces (friction and air resistance), causing the bike to accelerate.
A calculator has a small dark strip on the top that allows it to work without batteries. What type of energy is it collecting and using?
Solar (light/radiant) energy.
A student leaves a bowl of sugar water outside in the sun. Three days later, the water is gone but white crystals remain. Explain what happened to the water and the sugar.
The heat from the sun caused the water to evaporate, changing it from a liquid to a gas. The sugar does not evaporate, so it was left behind in the bowl as solid crystals.
You want to build a doorbell that only rings when you press a button. Should the circuit be naturally “open” or naturally “closed”? Explain your reasoning.
It should be naturally “open.” An open circuit has a break in the path, meaning electricity cannot flow and the doorbell stays silent. Pressing the button closes the circuit, completing the path and allowing electricity to flow to ring the bell.
You are designing a periscope to see over a wall. How many mirrors do you need at minimum, and how should they be positioned?
You need a minimum of two mirrors. They should be positioned at opposite ends of the tube, angled at 45 degrees, and facing each other so that light hits the top mirror, reflects down the tube to the bottom mirror, and then reflects out to the viewer’s eye.
A student wants to test if the weight of a paper airplane affects how far it flies. Identify the independent variable and one thing that should stay constant.
A student says that energy can be “used up” and disappear forever. Use the Law of Conservation of Energy to explain why they are incorrect.
The Law of Conservation of Energy states that energy cannot be created or destroyed; it can only change forms or be transferred from one object to another. The energy does not disappear; it simply transforms into a different type of energy, such as heat or sound.