Year 8 Energy Test Review

Comprehensive question-and-answer study flashcards covering key concepts for the Year 8 Energy Test, including types of kinetic and potential energy, conservation of energy, efficiency, and heat transfer methods.

What is required for objects to move?

Energy

What is kinetic energy?

Energy of motion

What is mechanical energy?

Energy due to motion of an object

What is thermal (heat) energy?

Energy due to vibration or movement of particles

What is sound energy?

Energy due to vibration transferred through matter in waves

What is electrical energy?

Energy due to the flow of charged particles

What is radiant (light) energy?

Electromagnetic energy that travels in waves that we can see

What is potential energy?

Stored energy

What is chemical energy?

Energy stored in the bonds between atoms

What is nuclear energy?

Energy stored in the nuclei of atoms

What is gravitational energy?

Energy stored in an object’s height

What is elastic energy?

Energy stored in stretched objects

What unit is energy measured in?

Joules

What does the Law of Conservation of Energy state?

Energy can neither be created nor destroyed, and energy can only be converted from one form of energy to another.

What is energy transformation?

Changing energy from one type to another type

Why are energy transformations not efficient?

Because non-useful energy outputs are produced (e.g. heat)

What is the formula used to calculate percentage efficiency?

$$\text{Percentage efficiency} = \frac{\text{useful energy output (J)}}{\text{total energy input (J)}} \times 100$$

What is energy transfer?

Moving energy of the one type to another object

In what direction is heat energy ALWAYS transferred?

From a hot object to a cold object

What is conduction?

Heat transfer due to objects touching each other

What is convection?

Heat transfer due to the movement of fluids

What is radiation?

Heat transfer due to the emission of infrared electromagnetic waves

What are objects that easily transfer thermal energy called?

Conductors

What are objects that slow the transfer of thermal energy called?

Insulators

What causes convection currents?

Hot fluids (liquids and gases) are less dense and rise up, and cold fluids are more dense and sink.

What are the specific characteristics of heat transfer by radiation?

It is invisible to the eye, is not affected by air flow, and can travel in the vacuum of space.