Science: Physics

Question 1

What is energy?

Answer 1

The ability to do work

The more energy something has, the more work it can do

Works transfers energy from one place to another or transforms energy from one type to another

Energy is always measured in Joules (J)

Question 2

What are some types of Kinetic Energy and what are their definitions?

Answer 2

Movement/Kinetic: Energy possessed by a moving object

Light: Any form of energy on the electromagnetic spectrum(light). Often visible

Sound: Energy that travels as vibrating waves and can be heard by our ears

Heat: A measure of the total kinetic energy possessed by particles in a substance

Electrical: Energy that causes charged particles to move

Question 3

What are some types of Potential energy and what are their definitions?

Answer 3

Gravitational: The stored energy in an object that is held over the surface of the Earth

Chemical: Energy stored within a substance, such as food and fuel, that may be released when the substance is burnt or digested

Nuclear: The energy stored within the nucleus of an atom

Elastic: Energy stored within a stretched or compressed object like a spring or elastic material

Question 4

What does the Law of Conservation of Energy mean?

Answer 4

Energy cannot be created nor destroyed, only transferred or transformed

This Law basically just means that energy never disappears

The total amount of energy always stays the same. The total amount of input energy is equal to the total amount of output energy

In most energy transfers, energy can be transformed into several different types of energy, some of which may or may not be useful

Question 5

What are Energy Flow Diagrams and how do you make them?

Answer 5

Energy flow diagrams are used to show energy transfers and transformations

Arrows are used to show the direction of energy movement and the forms of energy are labelled at each step

You don’t need to draw objects, you can simply write what they are and draw a box around them

Question 6

What are the 5 points of Particle Theory?

Answer 6

Matter is made up of tiny particles

Particles of matter are all in constant motion

Particles of matter are held together by electric forces

There are empty spaces between particles, these spaces differ with each phase (solid, liquid, gas)

Temperature affects the speed of the particles. The higher the temperature, the faster the speed of the particles. (This last point is called the Kinetic Theory of Matter)

Question 7

What is temperature and what does it indicate?

Answer 7

Temperature indicates how hot or cold something feels

It depends on how quickly the particles of a substance are moving

Temperature is a measure of the average kinetic energy of the particles

The particles in a hot substance are moving faster than the particles in a cold substance

Temperature is measured with a thermometer and the unity are ˚ C

Question 8

What is the difference of Heat and Temperature?

Answer 8

Heat is the total amount of energy, temperature Is the average amount of energy

Question 9

What is heat?

Answer 9

Heat is a form of energy

Heat describes the total energy of all particles within an object

Heat is measured in Joules

Question 10

What is Conduction?

Answer 10

Conduction is the process of heat transfer by vibrating the particles

When something heats up the particles vibrate, adjacent particles are vibrated by these particles and so on and so on

The passing on of the vibration causes the heat to also be passed on

Question 11

What is convection?

Answer 11

Convection is the transfer of heat in a liquid or gas due to less dense, warmer matter rising and denser, cooler matter falling

The particles in liquids and gases are more loosely arranged and therefore can flow

Gases and liquids are called fluids because they have the ability to flow

When particles in fluids are heated, they spread out making the matter less dense.

Question 12

What is radiation?

Answer 12

Heat can be transferred without particles vibrating or flowing

Radiation is the movement of heat in the form of electromagnetic waves which can travel through a vacuum

These waves travel at the speed of light. Infra-red radiation is heat energy transferred this way

All objects release/emit some infra-red radiation

When heat radiation hits an object it can either be absorbed, reflected or transmitted

Question 13

What is Static Electricity

Answer 13

Static electricity is a collection of negative charges that jump from one object to another

Question 14

What are electrostatic forces?

Answer 14

Opposites attract – positively and negatively charged object will move to stick together

Same charges repel – negative and negative or positive and positive want to push each other away

These attraction or repulsion forces are called electrostatic forces

Question 15

Examples of good and bad static electricity

Answer 15

Carpet static – bad when you get shocked

Aircraft refuelling – bad can cause an explosion

Photocopier – good this is how photocopiers work

Lightning – both. Bad if you get struck by lightning. Some artworks are creating by lightning hitting silica sand

Question 16

What is static electricity?

Answer 16

Collection of negative charges that jump from one object to another

Easier for atoms in some materials to give away electrons, atoms in some materials are happy to accept them

Materials like rubber, fur plastic give away electrons, to materials like hair, skin, metal

Jumping of electrons from one object to another = Static Electricity

Object that gives away electrons = Positively charged

Object that accepts electrons = Negatively charged

Static charge leaks away into surroundings, returns materials to original state

If build-up continues, electrons jump from negatively-charged to positively-charged = Equalising the charges

	- When done, they release energy
		○ Light energy
		○ Electrical energy
		○ Sound energy
                ○Heat energy

Question 17

What are Good & Bad Static Electricity

Answer 17

Good & Bad Static Electricity

- Carpet Static - Bad: when you get shocked
- Aircraft Refuelling - Bad: can cause an explosion
- Photocopiers - Good: because that's how they copy work
- Lightning - Both, Bad: If you get struck by lightning. Good: Artworks created by lightning hitting silica sand

Question 18

What is Current Electricity

Answer 18

Continuous movement of electrons through a conductor

Energy from moving electrons is transformed into different forms of electricity

• Eg. Light, Heat, Sound

Electricity used in homes is not static, made from flow of negative electrons, usually through metal wire or other electrical conductor, around a circuit

Movement of charge = Current Electricity

Question 19

What is Current

Answer 19

Rate of flow of electrons from one point to another

Measured by ammeter, unit of measurement = amps

Current = Actual “substance” flowing through wires of the circuit (Electrons)

Question 20

What is Direct Current

Answer 20

Batteries & cells produce direct current, electrons travel in one direction

Question 21

Whats is Alternating Current

Answer 21

Electrons travel in both directions, back & forth along a wire

Used at power outlets in buildings because it generates more power, easier to transmit & voltage can be increased/decreased using transformers

Question 22

What are the currents in parallel and series circuits

Answer 22

In series circuit, current is the same at any point

In parallel circuit, current distributed across the branches

Example of distribution of current through parallel circuit

• Series of water pipes arranged like parallel circuit, rate of water flow may differ between branches/sections of parallel circuit

Question 23

What is Voltage

Answer 23

Measure of amount of energy, supplied to the charges by the voltage source (Supply voltage), used by the charges as they pass through a component of a circuit

Voltage is pressure that pushes the current through the circuit

Measured by voltmeter, unit of measurement = Volts

Voltage is high when electrons are supplied a lot of energy or losing a lot of energy. Voltage = Low if electrons lack energy

Question 24

What is Resistance

Answer 24

Measures how difficult it is for an electric current to flow through a material/component

Resistance is friction that obstructs the flow of current through the circuit (Eg. Rocks in river)

If resistance = High, electrons lose energy, voltage & current decreases

Measured by digital multi-meter, unit of measurement = Ohms

Question 25

What are 3 Factors That Affect Resistance

Answer 25

Material the wire is made from

Length of the wire - Longer the wire, the more resistance there will be

Thickness of the wire - Thinner the wire, the more resistance there will be

Question 26

What is Ohms Law

Answer 26

Gives relationship between voltage, current, resistance in a circuit

Current passing through a conductor is proportional to the voltage over the resistance

Question 27

What are the Formulae for Ohms Law

Answer 27

Voltage = Current x Resistance

Current = Voltage / Resistance

Resistance = Voltage / Current

Question 28

What are electrical circuits?

Answer 28

Electric Circuits

An electric circuit is the path electrons take to transfer their energy

Electrons are conducted through the circuit, from the negative terminal of the energy source to the positive terminal

Electric circuits are made up of components which have universal symbols

There are two types of circuits:

Series

Parallel

Question 29

What are some main components of Electrical Circuits?

Answer 29

Components of Simple Electrical Circuits

An energy source (Battery or cell)

An energy user, e.g. a lightbulb

Metal wires connecting everything

Often there is a switch turning the circuit on or off – A break in an electrical circuit will stop the flow of electrons and turn off the energy user

Question 30

Chemical Energy as an energy source?

Answer 30

Chemical Energy as an Energy Source

A chemical cell stores chemical energy and transfers it to electrical energy when a circuit is connected

A battery is made up of 2 or more chemical cells

The chemical energy of the cells us used up as it pushes the current round a circuit

The current travels from the negative terminal of the battery, through the circuit, to the positive terminal of the battery

Question 31

Was that… A BEKY MOMENT

Question 32

How are series circuits arranged, what happens if a bulb blows out?

Answer 32

Series Circuits

The components are connected end-to-end, one after another. They make a simple loop for the current to flow around. If one bulb ‘blows’ it breaks the whole circuit and all the bulbs go out.