⚡ Chapter 3: Forces and Energy
Grade 8 Science Assessment
📝 Total Questions:
30
✅ Pass Mark:
70%
⏱️ Time:
45 minutes
1
What is density?
The amount of space something takes up
Mass per unit volume
The weight of an object
The color of a material
2
What is the formula for density?
density = volume ÷ mass
density = mass ÷ volume
density = mass × volume
density = mass + volume
3
How do you calculate the volume of a regular block?
Add the lengths of the sides
Multiply the lengths of the sides
Divide the lengths of the sides
Subtract the lengths of the sides
4
How do you find the volume of an irregular object?
Weigh it on a scale
Use the displacement method with water
Multiply its dimensions
You cannot find it
5
If something is more dense than water, what will happen?
It will float
It will sink
It will dissolve
It will evaporate
6
Why do gases have lower densities than liquids or solids?
They are lighter
The particles in a gas are far apart
They have no mass
They are invisible
7
What is heat?
The same as temperature
The total thermal energy of the vibrating particles in an object
Only found in fire
A type of light
8
What is temperature?
The total energy of all particles
The average energy of the particles in an object
The weight of an object
How hot it feels
9
What happens to particles when thermal energy increases?
They vibrate faster
They stop moving
They get heavier
They disappear
10
What is absolute zero?
0°C
-273°C (the lowest possible temperature)
-100°C
The freezing point of water
11
What does it mean when energy is conserved?
Energy is saved for later
The total quantity of energy stays the same
Energy is destroyed
Energy is created
12
In an electric lamp, 100J of electrical energy produces 10J of light and 90J of thermal energy. Is energy conserved?
No, energy is lost
Yes, 100J input = 100J output (10J + 90J)
No, more energy is created
It depends on the lamp
13
What does "dissipated" mean?
Energy is destroyed
Energy spreads out into surroundings and becomes less useful
Energy is saved
Energy is concentrated
14
Can energy be created or destroyed?
Yes, both can happen
No, energy cannot be created or destroyed, only changed or transferred
Yes, energy can be created but not destroyed
Yes, energy can be destroyed but not created
15
Which direction does thermal energy always move?
From colder places to hotter places
From hotter places to colder places
It doesn't move
In random directions
16
What does "colder" mean?
At a higher temperature
At a lower temperature
The same temperature
Zero temperature
17
What is dissipation?
Energy that spreads out and becomes less useful
Energy that is stored
Energy that is created
Energy that is destroyed
18
The rate or speed of thermal energy transfer increases when:
The temperature difference is smaller
The temperature difference between hot and cold place is larger
The objects are the same temperature
There is no difference
19
If a large block of iron and a small block of polystyrene both measure 1cm × 1cm × 1cm, which statement is true?
They have the same mass
Iron has a higher density than polystyrene
They have the same density
Polystyrene is heavier
20
What happens when a gas is compressed?
The density decreases
The density increases
The density stays the same
The gas turns to liquid
21
Why can a hot air balloon float?
The hot air inside is less dense than the colder air outside
The hot air is heavier
It is filled with helium
Magic
22
When liquids of different densities are added together carefully, what happens?
They always mix together
Less dense liquids float on the more dense liquids and form separate layers
They evaporate
They turn solid
23
Which has more total thermal energy (heat): a large glass of water or a small glass of water at the same temperature?
The small glass
The large glass (more particles = more total energy)
They have the same
Neither has thermal energy
24
In an energy diagram for a car engine, what does the energy input represent?
The kinetic energy of the car
The chemical energy in the fuel
The thermal energy wasted
The sound energy
25
What is thermal energy measured in?
Joules
Degrees Celsius
Grams
Meters
26
Thermal energy can be transferred between objects. What can it also be?
Destroyed
Stored in an object and eventually dissipate
Created from nothing
Frozen
27
Why does a sparkler at 1000°C not cause serious burns from one spark?
The spark is not hot enough
The mass of the spark is very small, so total thermal energy is small
Sparks cannot burn skin
The spark is made of water
28
What happens to particles as temperature decreases?
They move faster
They move more slowly
They stay the same
They disappear
29
Can the total energy output ever be greater than the total energy input?
Yes, always
No, because energy cannot be created
Yes, in some machines
Sometimes
30
What happens when you open a window on a cold day?
Thermal energy moves from outside to inside
Thermal energy moves from the warmer inside to the colder outside
No thermal energy moves
The room gets warmer
Submit Test
📊 Test Results
Retry Test