Year 9 Physics topic 1

What is energy?

Energy is the ability to make things happen, or the capacity to do work or cause change.

What are the main forms of potential energy?

Gravitational, elastic, chemical, nuclear, electrical, and magnetic energy.

What are the main forms of active energy?

Kinetic, heat, light, sound, and electrical energy.

What is energy transfer?

Energy transfer is when energy is passed on or moved from one object to another or to the surrounding environment.

Give an example of heat energy transfer.

Heat from a hot-water bottle is transferred from the bottle to you.

Give an example of light energy transfer.

Light travels from the Sun to Earth through space.

Give an example of kinetic energy transfer.

A person pushes a shopping trolley, transferring kinetic energy.

Give an example of sound energy transfer.

Music travels from a speaker to your ears through space.

Give an example of electrical energy transfer.

Electricity travels from a power station to your home through cables.

What is energy transformation?

Energy transformation is when energy changes from one form into another.

Give an example of light energy transforming into chemical energy.

Light energy from the Sun is transformed into chemical energy in plants during photosynthesis.

Give an example of chemical energy transforming into kinetic energy.

Chemical energy in food is transformed into kinetic energy when you exercise.

Give an example of electrical energy transforming into sound energy.

Electrical energy is converted into sound energy in speakers.

Give an example of gravitational energy transformation.

Gravitational energy can be transformed into kinetic and elastic energy in a bungee jumper.

What are the four primary mechanisms of energy transmission?

Mechanical, heating, radiation/waves, and electrical.

What is mechanical energy transmission?

It occurs when a physical force moves an object or matter.

What is radiation/wave energy transmission?

Energy travels through space or matter in the form of waves.

What is heating as a form of energy transmission?

Heat energy moves from a warmer object or area to a colder one through conduction and convection.

What is electrical energy transmission?

Energy is transmitted through the movement of charged particles, such as electrons, along a conductive path.

Do water particles travel across a lake with a wave?

No. The water particles move up and down while the wave transfers energy.

How does a wave transfer energy to a duck on a lake?

The wave transfers energy through the water, causing the duck to bob up and down without moving the water across the lake.

What is a wave?

A wave is a disturbance that transfers energy without moving matter.

What are the two main types of waves?

Transverse waves and longitudinal waves.

What is a transverse wave?

A transverse wave has vibrations at right angles to the direction the wave travels.

Give three examples of transverse waves.

Water surface waves, light waves, and string/rope waves.

What is a longitudinal wave?

A longitudinal wave has vibrations parallel to the direction the energy travels.

Give four examples of longitudinal waves.

Shock waves, sound waves, ultrasound waves, and compression waves in a spring.

What are the three important properties of waves?

Wavelength, amplitude, and frequency.

What is wavelength?

The distance between two matching points on a wave, such as crest to crest or trough to trough.

What does wavelength tell you?

It tells you how long each wave cycle is.

What is amplitude?

The height of a wave from the middle line to the crest or trough.

What does a larger amplitude mean?

A larger amplitude means more energy is being transmitted.

What is frequency?

The number of waves or vibrations produced each second.

What is frequency associated with in sound?

Pitch.

What happens when frequency increases?

The waves are closer together and the pitch is higher.

What happens when frequency decreases?

The waves are further apart and the pitch is lower.

What is the unit for frequency?

Hertz (Hz).

What does 1 Hz mean?

One vibration occurs per second.

What is the difference between energy transfer and transformation?

Transfer moves energy from one object or place to another without changing its form; transformation changes energy from one form into another.

What is energy transmission?

Energy moving through a medium or through space, such as sound travelling through air or waves moving through water.

How does a wave transfer energy without transferring matter?

Particles vibrate around their positions while the disturbance travels through them, carrying energy onward.

What is the relationship between amplitude and energy?

Greater amplitude means more energy is transmitted.

What is the relationship between frequency and pitch?

Higher frequency produces a higher pitch; lower frequency produces a lower pitch.

What is the difference between transverse and longitudinal waves?

Transverse vibrations are at right angles to energy travel; longitudinal vibrations are parallel to energy travel.