Name_____________________________

Teaching set_______________________

Northgate GCSE Science.

Knowledge Organiser Physics.

This booklet contains questions from topics that are covered

in Physics P1-P6. This is to be used throughout your GCSE

revision. Use it to help learn the definitions of common

scientific terms. You can get family members to test your

knowledge, make quizzes, games or flashcards.

As part of your homework mini quizzes will pop up during

lesson time based on the information inside this booklet.

The GCSE textbooks and other digital resources are available

online. www.Kerboodle.com. Your username is your initial

and surname e.g. jsmith and the institution code is po7. You

may also wish to use SAM learning for revision purposes.

Key to using this guide.

If you are entered into triple science you will need to know all of the knowledge

If you are entered into combined science you do not need to revise sections in bold.

If you are entered into combined science foundation you do not need to revise information in italics.

P1 – Radiation and Waves

1 What is the order of the electromagnetic spectrum?

(longest wavelength to shortest) Radiowaves, microwaves, infrared, visible light, ultra violet, x-rays, gamma rays

2 What is visible light? White light is a mixture of all the colours across the visible spectrum. ROY G BIV. (longest wavelength to shortest) Primary colours red, blue and green can make white light

3 What type of wave are electromagnetic waves? transverse

4 How are visible light, ultraviolet and x-rays emitted?

when electrons drop down energy levels

5 How is infrared radiation emitted? When atoms in molecules vibrate

6 How are gamma rays emitted? When there is a change in the nuclei of atoms (radioactive decay)

7 What happens when electromagnetic spectrum waves are absorbed?

All radiation causes heating as it is absorbed and molecules vibrate more, however UV, X-rays and gamma rays can also cause ionisation.

8 What does the term ionising mean? If an outer electron is excited with enough energy it can leave the atom or molecule. The atom or molecule is now a positive ion.

9 Why is ionising radiation dangerous? Ions can react further causing cell damage, either changing the cell making them more likely to replicate uncontrolled (possibly causing cancer). Or causing cell destruction

10 How does a household microwave work? The waves penetrate the food for a few cm. being absorbed by water, fat and sugar molecules in the food and causing it to heat up. The heat is then transferred throughout the food.

11 Give a use of radio waves. Used for transmitting information (television and radio)

12 Give a use of microwaves Communication (satellites and mobile phones)

13 Give a use of visible light Optical fibres to carry data over long distances, Light microscopes Looking at your own reflection and taking photographs.

14 Give a use of X-rays View internal structures of objects. The X-rays do not pass through (but are absorbed by) denser objects such as bone, therefore the plate remains white and produces a negative image. Continued exposure to X-rays causes cell damage. Lead shields are used to keep exposure to a minimum. - short term exposure the benefits are greater than the risk.

15 Give a use of gamma rays Used to sterilise medical instruments as gamma is absorbed

by bacteria and kills them. Sterilise food so food lasts longer Cancer treatment to killing cancer cells. Medical imaging.

16 On the electromagnetic spectrum which waves have the most energy and which the least?

Most energy - Gamma rays Least energy - radio waves

17 How do you calculate wave speed? Wave Speed (m/s) = distance travelled (m) / Time taken (s)

18 What is the wave equation? Wave speed (m/s) = Frequency (Hz) x Wavelength (m)

18 What are the units of frequency? (Hz) hertz but can also be given in kHz or MHz 1 kHz = 1000 Hz 1 MHz = 1000 000 Hz

19 How do you calculate frequency? The number of complete waves per second Frequency = Wave Speed/Wavelength

20 Draw and label a transverse wave

21 Draw and label a longitudinal wave

22 Draw a diagram to show reflection of a wave

A Ray diagram too?

23 What is the law of reflection? The angle of incidence (measured to the normal) is equal to the angle of reflection (measured to the normal). I=R

24 What causes refraction? When a wave passes through into a different medium, the wave speed is changed, however because the frequency is the same this changes the wavelength. the wave then changes angle.

25 Draw a diagram to show rays from a converging lens.

26 Draw a diagram to show rays from a diverging lens.

27 Explain how we see the colour red. White light is made up of red, orange, yellow, green, blue, indigo and violet. The light is either absorbed or reflected. For an object to look red it must absorb all the other colours and reflect red light. The red light is then detected by the cones (a specialised cell in the eye).

28 Explain how we see the colour yellow The object will reflect the two primary colours to make the secondary colour yellow. The light colours reflected are red and green. Blue is absorbed by the object.

29 List the energy stores Thermal Kinetic Nuclear Magnetic Chemical Gravitational

30 Give an equation to calculate the electrical energy transferred?

Energy transferred (J) = Power (W) x Time (s) Energy transferred (J) = Potential difference (V) x Charge (C)

31 What is the equation to calculate power? Power (W) = Work done (J)/ Time (s) Power (W) = Potential difference (V) x Current (A)

32 Draw a sankey diagram to represent the energy efficiency of a light bulb that uses 100J input energy, 75 J is given off as light and the rest as heat.

33 What are the two waves caused by an earthquake?

The two seismic waves are P wave (longitudinal waves) and s wave (transverse wave) remember P waves (push and pull) S waves (sideways)

34 What substances can P waves travel through? Solids and liquids

35 What substances can S waves travel through? Solids only

36 Give a use of ultrasound To scan unborn babies. A high frequency sound is sent and reflects from soft tissue, a detector receives the sound and an image is then decoded from the reflected sound.

P2- Sustainable Energy

1 How do you calculate the cost of energy used for a domestic energy bill?

Cost of energy transferred=number of units x cost per unit Pence (KWh) (p/KWh)

2 What happens when energy is dissipated? Dissipated energy is transferred to a less useful energy store, such as thermal store.

3 How could you reduce the amount of energy dissipated?

By lubrication, you reduce the amount of work done and the amount of heating of the surroundings. By Insulation, you cut down the transfer of energy between two objects at different temperatures.

4 What is the Law of conservation of energy? Energy cannot be created or destroyed, only transferred.

5 What is a closed system? A closed system has a defined start and end, the total energy in the system remains the same.

6 What is thermal conductivity? Informs how fast energy is transferred by conduction

7 How do you calculate the efficiency? efficiency=useful energy transferred x 100 Total energy transferred.

8 Why do we use more energy resources in the modern world than in the past?

Population increase Modern technology such as communication, possessions and transport. Traveling further.

9 What is a fossil fuel? Formed from the remains of trees and sea creatures over millions of years ago. They are a finite resource, meaning they cannot be replaced and run out. Coal, oil and natural gas are examples of fossil fuels.

10 What are renewable resources? Resources that can be used to generate energy without being used up. Examples include wind, solar, hydroelectric, tidal and biogas.

11 How is electricity generated? Moving a magnet in and out of a coil of wire induces a voltage.

12 How can the amount of electricity being generated be increased?

Increase size of generator, increase strength of magnet, increase speed magnet spins.

13 How is electricity generated in a thermal power station?

Fuel is burned to boil water → steam passes through a turbine → turns a generator → voltage is induced

14 How is electricity generated in a nuclear power station?

Uranium atoms split releasing energy→ energy is used to boil water → steam passes through a turbine → turns a generator → voltage is induced

15 What are the advantages of nuclear fuel? Releases more energy than the same amount of fossil fuel. Produces less waste than fossil fuel. No CO2 is produced.

16 What are the disadvantages of nuclear fuel? Nuclear waste must be safely stored to prevent contamination. Expensive to decommission power plants when they reach the end of their useful life.

17 What is alternating current? Produced by an alternating voltage, where a magnet rotates in a coil of wire. The changing poles constantly changes the magnetic field around the coil. Mains electricity is generated using alternating current.

18 What is direct current? Direct voltage produces a direct current in a battery-powered device, such as a phone. The voltage does not change direction.

19 What is the National Grid? The UK electrical distribution system that connects consumers to power stations that generate electricity.

20 Why is a high voltage used in the National Grid?

It is more efficient to use a higher voltage with a lower current to deliver the same power. With a smaller current, less energy is lost heating the wires.

21 What are each of the wires inside a plug? Earth- green and yellow. Neutral- blue. Live- brown.

P3- Electric Circuits

1 What is an electrical circuit? A complete loop, where charges are present at all times

but are made to move in one direction by a potential

difference provided by a battery (power source). A break

in the circuit means the charge is no longer able to move

in one direction

2 What is an electric current? A flow of charges.

3 How do you measure a current and what are the

units?

Using an ammeter, the units are amperes, amps (A).

1 ampere = 1 coulomb/second

4 What is the unit of charge? coulomb

5 How could you calculate the charge if given the

current and time taken?

Charge (c) = current (A) x time (s)

6 Describe a series circuit All components of the circuit are arranged in a single loop.

7 What factors affect the size of a current through a

circuit?

Voltage of battery

Resistance of the components.

8 What is voltage? The measure of the amount of “push” a battery has. Also

known as potential difference. The greater the potential

difference of the battery the higher the voltage and the larger

the current.

9 What is resistance? As charges move through a substance, they collide with

other ions, so the temperature increases (of a wire or

solution). The higher the resistance the smaller the current

10 What equipment do you use for measuring

voltage?

A voltmeter

11 How could you calculate the resistance in a

component?

By measuring the current and the voltage you can then use

the equation. Resistance = Voltage

Current

To calculate the resistance in ohms (Ω)

12 What is Ohm’s law? The current through a conductor is proportional to the

voltage across it provided it stays a constant temperature.

(applies to metals).

13 What is a fixed resistor? A component that Ohm’s law is true across a range of

currents and voltages.

14 Why does Ohm’s law not apply to every

component?

As a current causes components to heat up, adjusting the

temperature and the resistance.

15 Describe a parallel circuit A circuit where more than one loop is formed. Each is of the

loops can work independently to the other.

16 Describe the total resistance when resistors are

connected in series and parallel circuits

In a series circuit the total resistance will be larger than when

on their own as the battery has to push through all the

resistors. R = R1 + R2

In a parallel circuit the total resistance will be smaller than

when on their own as there are additional paths the charges

can take.

17 Describe the difference in voltage across the

components in a series and parallel circuit.

In a series circuit the sum of potential difference across each

component is equal to the potential difference across the

battery. V = V1 +V2 ……..

The actual voltage depends on the resistance of each

component.

In a parallel circuit the potential difference across each

component is the same at the potential difference across the

battery. V = V1=V2…….

18 Describe the current of a component in a parallel

circuit.

The current in a component will be dependent on the

resistance. A big resistance results in a small current. In

parallel the current in each loop will total the current either

side of the battery.

19 What is the purpose of a variable resistor in a

circuit?

It can be used to control the amount of current in a circuit.

20 What is a diode? A diode will only allow the flow of current in one direction.

By having a very high resistance in one direction and a low

resistance in the other.

21 Describe a potential divider and an example of its

use.

Two resistors are connected in series, with unequal

resistance. If one is a variable resistor it will allow for

electrical equipment which we can control the voltage.

22 What is electrical power? The rate of energy transferred, measured in watt (W)

23 How could you increase the power of a circuit? By increasing the current by adding a component in parallel.

By increasing the potential difference by adding a cell or

increasing the voltage.

24 What is the equation that links power, current and

potential difference?

Power (W) = current (A) x potential difference (V)

P=IV

25 How would you calculate the work done using

power?

Work done (J) = power (W) x time (s)

W=Pt

26 What is the role of transformers in the National

Grid?

They step up the voltage from the power station to lower the

current and reduce power loss through the transmission

cables.

They then step it back down to 230 V for use in homes.

Increasing the current.

27 What is a magnetic field? Is the region around a magnet that another magnet will feel

a force

28 How does a compass work? It aligns itself with the Earth’s magnetic field. The north

seeking end of the compass aligns with the North Pole.

29 What is a permanent magnet? A material that retains its magnetism out of a magnetic field.

Such as Iron.

30 What is induced magnetism? When a material becomes magnetised when in a magnetic

field, but later loses its magnetism.

31 Describe a solenoid A coil of wire that conducts a current to produce a magnetic

field.

32 How could you increase the magnetic field of a

solenoid?

By placing a iron core in the center.

By increasing the amount of coils

By increasing the current.

33 Describe how electromagnets work and their

uses.

A coil of wire around an iron core creates a magnet. As the

magnet only works with the current on and the current can

be switched on and off, the magnet can be switched on and

off.

Uses include

scrap merchants picking up cars to move them.

Security doors

Speakers/headphones.

34 What is Fleming’s left-hand rule? A way of predicting the direction of the force in a motor from

the direction of current and magnetic field.

Thumb = Motion

First finger= Field

Second finger = Current.

35 How do you calculate the force created by an

electric motor?

Force (N) = magnetic field strength (B) x current (A) x length

of wire (m)

F=BIL

36 How would you increase the strength of force on

a wire in an electric motor?

Increasing the strength of magnetic field

Increasing the current in the wire

Increasing the length of the wire/number of coils.

37 What is an alternator? A generator that produces alternating current as a coil

rotates in a magnetic field.

38 What is the role of a commutator? To adapt an alternator to produce direct current instead

of alternating current. They replace slip rings in the

alternator.

39 Explain why the voltage across the coil of a

alternator/dynamo is zero when the coil is

vertical

The force of the wire is at right angles to the magnetic

field and electrical current. When the coil is vertical

there is no potential difference.

40 Explain how a transformer works When a current in an electromagnet inside the

transformer is switched on a current is generated in a

second coil on the same iron core.

41 How do you calculate the output voltage of a

transformer

Pd across primary coil Vp = No of turns in primary coil

Pd across secondary coil Vs No of turns in secondary coil

P4 - Explaining Motion

1 What is a force? A push, pull or twist.

2 What is Newton’s Third Law of Motion? For every action, there is an equal and opposite reaction.

3 Explain what is meant by a contact force A force caused by two objects touching

4 Give three examples of forces that act over a

distance.

Gravity, magnetism and electrostatic forces

5 What is the force that exerts when something

presses on it called?

Normal contact force

6 What is weight and how is it calculated? Weight is a force of gravitational attraction. It can be

calculated by

Weight(N) =mass (Kg) x gravitational field strength (N/Kg)

7 What is the gravitational field strength on Earth? Approx 10N/Kg

8 What is meant by a vector? A quantity with a size and direction, for example 3 m/s due

north.

9 What is a resultant force? An addition of several forces, taking into account their size

and direction.

10 How do you calculate the speed of a moving

object?

Average speed (m/s) = distance (m)

Time (s)

V=S

t

11 What is instantaneous speed? The speed and object is travelling at a specific time.

12 What is displacement? The straight-line distance between the starting point and

finishing. It is a vector as it has magnitude and direction

13 How do you calculate acceleration? Acceleration (m/s2 ) = change in speed(m/s)

Time (s)

14 Describe how you could calculate the speed from

a distance time graph

The gradient of the slope tells you the speed at that time.

Take two points on the slope of the line. Take the values

of the points on the y axis and subtract. Then take the

values from the x axis and subtract. The difference in Y

divided by the difference in x is the gradient.

The steeper the slope the faster the speed.

15 If a line has a gradient of zero in a distance time

graph, what does this mean?

A gradient of zero would mean that the motion has stopped.

(time is still proceeding, but distance is not changing).

16 On a speed time graph what does a line of zero

gradient mean?

A gradient of zero would mean that the speed is constant

during that time. (time is still proceeding, but speed has not

changed).

17 How could you find the distance travelled from a

speed-time graph ?

Distance is the area of the enclosed shape under the line.

18 What is the acceleration of free fall? Any falling object will fall with the same acceleration of

10m/s2 if no other forces are acting upon it.

18 What is a free-body diagram? A diagram showing all the forces acting on an object.

19 How can you draw a good free-body diagram? No forces on other objects are shown

The forces are shown by straight arrows

Arrows start in the object or on the surface

All arrows are labeled

No object - Object is represented by a dot.

20 Describe how to use vector diagrams to calculate

the resultant force.

Choose a scale to represent the forces on a page

Draw arrows to represent the forces taking into

account the angle between those forces.

Draw an arrow to connect the two force arrows, this

is the resultant vector, mark with a double

arrowhead.

Measure the length of resultant arrow, (magnitude)

Measure the angle between the resultant force and

two original forces. (direction)

21 What is momentum? A change in an object’s motion it can be calculated by

Momentum (Kg m/s) = mass (Kg) x Velocity (m/s)

M= mv

22 What is the conservation of momentum? Momentum is conserved and does not change during a

collision as long as no other forces are acting on it.

The momentum is the same before and after the collision.

23 Explain Newton’s first law If the resultant force is zero there is no change in the motion

of an object.

24 Explain Newton’s second law If resultant force is not zero there will be a change in the

motion of an object. Usually an acceleration (change of

speed can be positive or negative)

It can be calculated using

Force (N) = mass (Kg) x acceleration (m/s2)

F=ma

25 What is centripetal force? Give and example of

centripetal force

The resultant force where two forces are acting at 90o.

Which results in circular motion. For example satellites in

orbit.

The object moves at a constant speed, but it’s velocity

changes due to a contact force making it change direction.

26 Describe a moment of a force. A moment is the rotational effect of a

force.

27 What is the purpose of levers and gears They are used to transmit rotational forces, a lever

allows a mechanical advantage, by reducing the force

needed to lift a load.

28 What is the resistance to change of motion is

called?

Inertia.

29 Describe what is meant by a stopping distance It is the distance that it takes to stop completely, from the

moment of seeing a hazard. In car car to things affect

stopping distance, thinking distance (speed x reaction time)

and braking distance (mass and friction).

30 What is the change of acceleration during an

emergency stop?

From the speed travelling to Zero.

31 Why are cars fitted with crumple zones? To increase the time of the collision which reduces the

force.

Change of momentum = force x time.

32 How does a seat belt work? It slows the speed at which the passenger moves forward,

the change of momentum takes longer so the force is less.

33 What is the energy of a moving object called? Kinetic energy

34 What is work done? When a force makes something move, it transfers energy

to make it happen, that energy is work done

35 How could you calculate work done? Work done (J) = Force (N) x distance moved (m)

W=Fs

36 How can you calculate kinetic energy? Kinetic energy (J) = ½ mass (Kg) x (Speed (m/s))2

KE = ½ mv2

37 How can you calculate gravitational potential

energy?

Gravitational potential energy = weight(N) x height (m)

Weight = mass x gravitational field strength.

GPE = mgh

38 Describe what would happen to the energy in a

roller coaster about to drop down the track

As the roller coaster is lifted it has energy in its gravitational

store which can be calculated using GPE = mgh. As it

descends the track the gravitational store is decreased and

the kinetic store is increased, by the same amount. Energy

is conserved.

39 What is power? Power is the rate at which energy is transferred.

Power (W) = work done J()

Time taken (s)

40 What are the units of power? Watt (W) or Joules per second. (J/s)

P5- Radioactive Materials

1 What are some examples of radioactive

elements?

Uranium, plutonium, radon and radium.

2 What equipment can be used to detect radiation? A Geiger counter.

3 What does it mean if something is radioactive? The material, atom or element produces ionising radiation

from the unstable nucleus of the atom.

4 What is radioactive decay? The spontaneous change in the nucleus of an unstable

element, giving out alpha, beta or gamma radiation. Alpha

and beta emissions result in new elements.

5 Name four types of radiation. Alpha, beta, gamma, neutron.

6 What is ionising radiation? Radiation with sufficient energy to remove electrons from

atoms in its path. Examples such as ultraviolet, X-rays and

gamma rays can damage living cells.

7 Draw and label the nuclear model of an atom.

8 Describe the key points of the plum-pudding

model of the atom.

The model was proposed by J.J. Thompson who thought

that an atom consisted of tiny negatively charged

electrons moving about in a positively charged sphere.

9 What experiment was used to discover the

nucleus within an atom? Describe this

experiment.

Ernest Rutherford’s gold foil experiment:

A source of alpha radiation is directed at gold foil in a

vacuum chamber.

While some alpha particles passed through the foil, a small

number of alpha particles were reflected back to the

source (back-scattered). This highlighted the presence of

the positive nucleus as the negative electrons were

deflected.

10 What is an isotope? An atom of the same element with different numbers of

neutrons in the nucleus and therefore a different mass

number.

11 What are the three subatomic particles? Protons, neutrons and electrons.

12 On a chemical symbol there are two numbers: the

proton number and the nucleon number - what do

they both show?

Proton number = the number of protons in the nucleus of

an atom.

Nucleon number(atomic mass) = the total number of

particles (protons and neutrons) in the nucleus of an

atom.

13 What is an alpha particle? An alpha particle has two protons and two neutrons - it is

the same as a helium nucleus. The least penetrating but

most ionising form of radiation.

14 What is a beta particle? A high-speed electron produced from the nucleus of an

atom in radioactive decay. More penetrating than alpha

radiation but less so than gamma radiation.

15 What is gamma radiation? The most penetrating form of ionising radiation produced

by the nucleus of an atom in radioactive decay. It is the

most energetic part of the electromagnetic spectrum.

16 Write a nuclear equation for the alpha decay of

17 Write a nuclear equation for the beta decay of

18 Write a nuclear equation for the neutron

emission of

19 What is transmutation? The changing of one element into another due to a change

in protons. Can happen during radioactive decay or

nuclear fusion.

20 What is radioactive activity? The rate that radiation is emitted from a radioactive

material. Measured in becquerel (Bq).

21 What is the term half- life? It is the time taken for the activity to drop by a half.

22 Draw a diagram to show a decay curve.

23 How can carbon be used to date materials? Carbon exists as the isotope Carbon 14. The proportion of

carbon 14 will get less as it decays. By measuring the

proportion of carbon 14 left the age of organic materials

can be calculated.

24 What is the radiation dose? Measure of energy transferred when ionising radiation is

absorbed. It is measured in millisieverts (mSv)

25 What factors affect the radiation dose? The amount of radiation reaching the body

The type of radiation -

For example alpha is the most ionising, and would cause

the most damage but has the smallest range in air so is

only damaging if inside the body. Gamma is the least

ionising but is the most penetrating.

26 Where does background radiation come from? From natural sources such as radon gas from the ground,

cosmic rays, gamma rays from buildings and medical uses.

27 How is radiation used in diagnosis, specifically

kidney problems?

Tracers (Technetium 99m) are injected into the patient.

They give out gamma radiation inside the kidneys, any

areas that are black or do not glow are damaged. All

normal working parts will glow.

28 How is radiation used to treat thyroid cancer? The patient will swallow iodine 131 which decays to

xenon. The iodine collects in the thyroid as it is needed to

make hormones. The beta radiation is absorbed and will

kill the remaining cancer cells.

29 What is nuclear fission? The splitting of a nucleus into two.

30 What is a chain reaction? When a neutron causes another nuclei to split, which in

turn releases more neutrons to cause more nuclei to

split.

31 What is Uranium-235 used for? It is used as a nuclear fuel, where contained in fuel rods

it will undergo nuclear fission. Rod will get extremely

hot.

32 What are control rods? They contain boron which can absorb neutrons therefore

controlling the reaction rate within the reactor.

33 What is plutonium used for? It can be used for nuclear weapons, it is produced in

nuclear reactors.

34 What is nuclear fusion? Joining of two nuclei of two hydrogen atoms to form

helium.

35 Where does nuclear fusion take place? In the sun and stars

36 Why can we not use fusion to produce clean

energy?

It takes vast amounts of energy to overcome the electric

repulsive force, which happens at high temperatures. It

takes more energy for the reaction to happen that the

energy released. It is also difficult to control the reaction

and keep it going.

37 How does an H bomb work? An atomic bomb is used to compress hydrogen so that it

fuses and release more energy than the atomic bomb

P6- Matter - Models and Explanation

1 How do you calculate density? Density (Kg/m3) = mass (Kg)

Volume (m3)

2 What is specific heat capacity? It is the amount of energy you need to transfer to change

the temperature of 1Kg of substance by 1oC.

3 What is specific latent heat? It is the amount of energy you need to transfer to change

the state of 1Kg of the substance

4 What do the flat bits (0 gradient) of a heating or

cooling curve show? Labelled on this graph B and

D

The energy is being transferred to the substance but it is

not raising the temperature. This is equal to the latent

heat needed to change the state of the substance.

5 What holds the particles together in a solid or

liquid?

Intermolecular bonds in simple covalent molecules (bonds

between the particles).

Metallic bonds (electrostatic bonds in metals).

Covalent bonds in giant covalent molecules (shared

electrons).

Ionic bonds in salts (electrostatic bonds between ions)

6 What is sublimation? Change from a solid to a gas without being a liquid.

7 What is the spring constant? Spring constant (N/m) = force (N)

Extension (m)

Hooks law states that the force is directly proportional to

the extension of an elastic material.

8 How do you deform a spring? By increasing the force beyond the elastic limit. The spring

will no longer return to its original shape. It has become

plastic.

9 How do you calculate how much force in stored in

a spring?

Work done = ½ Force x max extension.

Energy stored = ½ spring constant x max extension2

10 How do you calculate pressure on a solid? Pressure (Pa) = Force (N)

Area (m2)

11 What is the unit of pressure? Pascal (Pa) or Newtons per meter2 (N/m2)

12 How do you calculate pressure in a fluid? Pressure (Pa) = density x depth x gravitational field

strength

P=phg

13 Describe why bubbles rise In a fluid pressure is acting in all directions inwards on

the bubble. The greater the depth, the greater the

pressure.

This means the bottom of the bubble has a greater

pressure than the top of the bubble. The force is

unbalanced creating upthrust. The bubble rises.

14 What is Boyle’s Law? In a gas if the temperature is the same.

The volume of gas is inversely proportional to the

pressure.

As the pressure goes up, volume goes down.

pV=k

(k is a constant that is dependent on the gas and

temperature)

15 Describe the solar system. Star at the centre (the sun).

8 Planets in orbit around the sun.

Four inner rocky planets are Mercury, Venus,

Earth and Mars.

Four outer gas giants are Jupiter, Saturn,

Uranus and Neptune.

Between Mars and Jupiter is the asteroid belt

containing most of the asteroids in the solar

system.

16 What is the name of our galaxy? The Milky Way.

17 What is a nebulae? A cloud of dust and gas in space.

18 Describe the birth of the sun. A nebula containing hydrogen and helium collapsed as

the particles were attracted.

The distances became smaller so the gravitational

attraction increased.

Particles accelerated inwards and the density

increased, the temperature increased and pressure

increased.

The gas became plasma, as mixture of ions and

electrons.(P5)

Nuclear fusion starts and energy is emitted as

electromagnetic radiation (P1)

18 How did Edwin Hubble conclude that galaxies

are moving away from us?

By measuring light given out from the galaxies, which

should emit particular wavelengths, he recognised that

the wavelengths were shifted to longer wavelengths.

This is known as red shift .

The further away the galaxy the faster the velocity.

How science works

1. What is meant by an outlier? It is a value that is not expected and is caused by random errors. The reading should be taken again or not used during calculations.

2. What is meant by accuracy? describes how close the result is to the true value

3. What is meant by precision? describes the measure of spread in the data, a small spread is more precise.

4. What is the independent variable? The variable that we change in an experiment

5. What is the dependent variable? The variable that is measured.

6. What is a control variable? The variable that are kept the same to allow comparisons of the data collected.

7. What is a random error? A source of variation in the measurements that can not be avoided.

8. What is a systematic error? An error that is the same in all data and repeated. Good example include using uncalibrated equipment.

9. How should you measure liquids accurately. By taking the measurement from the bottom of the meniscus (bubble). Equipment such as a burette, glass pipette and filler and a volumetric flask are more accurate than beakers and

measuring cylinders.

10 What is the standard unit (SI) of: mass length time temperature area volume BMI Light intensity amount of substance concentration density pressure energy

Kilogram (Kg) meters (m) seconds (s) degrees Celsius (oC) or Kelvin (oK) meter squared (m2) meter cubed (m3) or decimeter cubed (dm3) Kilogram per meter squared (Kg/m2) watt per meter squared (W/m2) mole (mol) mole per decimeter cubed (mol/dm3) kilogram per meter cubed (Kg/m3) pascals (Pa) joule (J)

Useful Equations.

density (kg/m3) = mass (kg)/volume (m3)

distance travelled (m) = speed (m/s) x time (s) s=vt

acceleration (m/s2) = change in velocity (m/s)/time (s) a= v-u t

kinetic energy (J) = 0.5 x mass (kg) x (speed (m/s))2 KE = ½ mv2

force (N) = mass (kg) x acceleration (m/s2) F=ma

momentum (kgm/s) = mass (kg) x velocity (m/s) Momentum = mv

work done (J) = force (N) x distance (m) (along the line of

action of the force)

W=Fs

power (W) = work done (J)/time(s) P = w/t

force exerted by a spring (N) = extension (m) x spring constant

(N/m)

F= Kx

gravity force (N) = mass (kg) x gravitational field strength, g

(N/kg)

F=mg

(in a gravity field) potential energy (J) = mass (kg) x height (m) x

gravitational field strength, g (N/kg)

PE gravity = mgh

pressure (Pa) = force normal to a surface (N)/area of that

surface (m2)

P= F A

moment of a force (Nm) = force (N) x distance (m) (normal to

direction of the force)

Moment = Fs

charge flow (C) = current (A) x time (s) Q=It

potential difference (V) = current (A) x resistance (Ω) V=IR

energy transferred (J) = charge (C) x potential difference (V) W=QV

power (W) = potential difference (V) x current (A) = (current

(A))2 x resistance (Ω)

P=IR=I2R

energy transferred (J, kWh) = power (W, kW) x time (s, h) E=Pt

wave speed (m/s) = frequency (Hz) x wavelength (m) v=fƛ

efficiency = useful output energy transfer (J)/input energy

transfer (J)

change in thermal energy (J) = mass (kg) x specific heat

capacity (J/kg°C) x change in temperature (°C)

W=mcΔt

thermal energy for a change in state (J) = mass (kg) x specific

latent heat (J/kg)

W=mL

pressure (Pa) x volume (m3) = constant (for a given mass of gas

and at a constant temperature)

Pv=constant (for a given gas at a given

temp)

pressure due to a column of liquid (Pa) = height of column (m)

x

density of liquid (kg/m3) x g (N/kg)

P=pgh

(final velocity (m/s))2 - (initial velocity (m/s))2 = 2 x acceleration

(m/s2) x distance (m)

V2-u2=2as

energy transferred in stretching (J) = 0.5 x spring constant

(N/m)

x (extension (m))2

W=½ Kx2

force on a conductor (at right angles to a magnetic field)

carrying a current (N) = magnetic field strength (T) x current

(A) x length (m)

F=BIL

potential difference across primary coil (V)/potential

difference across secondary coil (V) = number of turns in

primary coil/number of turns in secondary coil

Vp = Np

Vs N s

potential difference across primary coil (V) x current in primary

coil (A) = potential difference across secondary coil (V) x

current in secondary coil (A)

Vp Ip = V s I s