5.3 describe experiments to determine density using direct measurements of mass and volume

Using a set mass of one object (eg 100g of water) change the space its in (eg 200ml cylinder taking ten off the ml each time.) Use the formula mass/volume to find the density, it will go up as the volume decreases.

5.2 know and use the relationship between density, mass and volume

Density= mass/ volume

p= m/V

5.7 understand the changes that occur when a solid melts to form a liquid, and when a liquid evaporates or boils to form a gas

Particles in a solid don't move; but if they are heated they gain energy and move, if they move enough they will become a liquid because the particles will bounce off each other moving them further apart.

Similarly, a liquids particles have some energy, but if they gain more they will bounce off each other more frequently moving them further apart; eventually they are far enough apart that it is a gas.

5.8 describe the arrangement and motion of particles in solids, liquids and gases

Solid: low energy; little movement, vibrating on the spot

Liquid: some energy; some movement; particles collide, bouncing apart and creating space between particles

Gas: lots of energy; lots of movement; particles collide a lot, bouncing apart more creating lots of space between particles 

Revesion

 Here are five simple steps to an easy revision timetable!

Step 1

List your subjects and break them down into topics.

Step 2

Write next to each topic how much time you think you need to dedicate it. Some you may find easy and only need an hour or two, others may require one or two days. 

Step 3

Mix your topics up, grouping smaller ones and making sure you don't have all your nightmare subjects together! Make sure to prioritise those extra tricky ones, and don't leave any out!

Step 4

Begin adding to your calendar - allocate times of the for revision and breaks!

Here's an example timetable:
8am - Wake Up
8:30 - Breakfast
9am - Revision
10am - Break: TV
11am - Revision
12:30 - Lunch
1:30 - Revision
3pm - Break: Brisk walk in park
3:30 - Revision
5PM - Dinner.

You may find you prefer shorter, more frequent revision sessions. Work out what's best for you, don't overwork your brain or you won't remember the facts and all that hard work will go to waste! 

Step 5

5. Cross off each session as you complete it, this gives you an awesome feeling of accomplishment as you finish each one.

Bonus Tip:

Put your timetable on a wall where others can see it to keep you on track and motivated! Good luck! :)

4.17 describe the advantages and disadvantages of methods of largescale electricity production from various renewable and nonrenewable resources.

Fossil fuels: non renewable; release CO2.

Burning wood: renewable; release CO2; destroy habitats.

Wind power: visual pollution; produces small amounts of electricity for space and effort in comparison to other methods.

HEP: expensive to set up; limited places to put it; can kill fish.

Solar cells: rely on the weather.

Nuclear power: dangerous; many waste products.

There are many more types of power and fors/againsts but these are a few important ones.

4.16 describe the energy transfers involved in generating electricity using several different methods

• wind- the kinetic energy from the wind, turns a turbine which turns a generator which produces electrical energy
• water- Kinetic energy from water, turns a turbine which turns a generator which produces electrical energy
• geothermal resources- Thermal energy heats water, water turns into steam, the thermal energy of the steam turns a turbine which then has kinetic energy, the turbine turns a generator which produces electrical energy
• solar heating systems- Light energy from the sun into thermal energy in water
• solar cells-convert light energy from the sun into electrical energy
• fossil fuels- Chemical energy is burnt to form heat energy, this turns into heat energy in water, this turns into kinetic energy in a turbine, this turns into electrical energy in a generator.
• nuclear power- kinetic energy in uranium, heat energy in water, kinetic energy in turbine, electrical energy in generator.

Energy resources

•Renewable source of energy: is inexhaustible, for example solar, hydroelectric, wind etc.
•Non-renewable source of energy: is exhaustible for example fossil fuels
•fuels can be burnt (or nuclear fuel can be forced to decay) in thermal power stations to transform the chemical energy stored to thermal energy which makes steam which turns turbines (kinetic energy) to produce electricity.
-advantage: cheap, plentiful, low-tech
-disadvantage: harmful wastes -produces greenhouse gases and pollutant gases, radiation...
•hydroelectric dams: river and rain water fill up a lake behind a dam. As water rushes down through the dam, it turns turbines which turn generators.
•tidal power scheme: a dam is built across a river where it meets the sea. The lake behind the dam fills when the tide comes in and empties when the tide goes out. The flow of water turns the generator.
 -advantage: no greenhouse gases are produced
 -disadvantage: expensive, can’t be built everywhere
•wave energy: generators are driven by the up and down motion of the waves at sea.
 -advantage: does not produce greenhouse gases
 -disadvantage: difficult to build
•geothermal resources: water is pumped down to hot rocks deep underground and rises as steam.
 -advantage: no carbon dioxide is produced
 -disadvantage: deep drilling is difficult and expensive
•nuclear fission: uranium atoms are split by shooting neutrons at them.
-advantage: produces a lot of energy from using very little resources
-disadvantage: producing radioactive waste
•solar cells: are made of materials that can deliver an electrical current when they absorb light energy •solar panels: absorb the energy and use it to heat water
-advantage: does not produce carbon dioxide
 -disadvantage: variable amounts of sunshine in some countries

Scalars and vectors

• A scalar is a quantity that only has a magnitude (so it can only be positive) for example speed. A vector quantity has a direction as well as a magnitude, for example velocity, which can be negative. • More ways to add vectors (Pythagoras’s theorem and the parallelogram rule):

Newton's Law

Newton’s 1st law of motion: If no external force is acting on it, an object will, if stationary, remain stationary, and if moving, keep moving at a steady speed in the same straight line Newton’s 2nd law of motion: F = m × a -acceleration is proportional to the force, and inversely proportional to mass Newtons 3rd law of motion: if object A exerts a force on object B, then object B will exert an equal but opposite force on object A or, more simply: To every action there is an equal but opposite reaction

Mass and weight

• Mass: the property of an object that is a measure of its inertia (a resistance to accelerate), the amount of matter it contains, and its influence in a gravitational field. • Weight is the force of gravity acting on an object, measured in Newtons, and given by the formula: Weight = mass × acceleration due to gravity • Weights (and hence masses) may be compared using a balance

Speed, velocity and acceleration

• Speed is the distance an object moves in a time frame. It is measured in metres/second (m/s) or kilometres/hour (km/h). speed = distance moved / time taken
• Calculating distance travelled: -with constant speed: speed × time -with constant acceleration: (final speed + initial speed)/2 × period of acceleration • Acceleration is the change in velocity per unit of time, measured in metres per second per second, or m/s2 or ms -2 . average acceleration = change in velocity / time taken a = v - u / s An increase in speed is a positive acceleration, a decrease in speed is a negative acceleration / deceleration / retardation. • If acceleration is not constant, the speed/time graph will be curved. • The downwards acceleration of an object is caused by gravity. This happens most when an object is in free fall (falling with nothing holding it up). Objects are slowed down by air resistance. Once air resistance is equal to the force of gravity, the object has reached terminal velocity. This means that it will stay at a constant velocity. (This varies for every object). The value of g (gravity) on Earth is 9.81m/s2 . However 10m/s2 can be used for most calculations. Gravity can be measured by using: Gravity = 2 x height dropped / (time)2 g = 2h / t2 This only works when there is no air resistance, so a vacuum chamber is required.

1.32 understand gravitational field strength, g, and recall that it is different on other planets and the moon from that on the Earth

Gravitational feild strength is how strongly something pulls an object towards it.
Earth has a higher gravitational feild strenght than the moon: on earth we are pulled down so much that we can jump only for a few seconds; on the moon the time you can jump for is longer as it is pulling you back in with a weaker gravitational feild.
The reason for this difference is mass, the earth has more mass than the moon and so has a bigger gravitational field strength. Bigger planets than earth will have a higher gravitational field strength.

1.34 describe the differences in the orbits of comets, moons and planets

Planets orbit in circles, where as comets orbit in ellipses (ovals) as does the moon.

1.36

(understand that:  the universe is a large collection of billions of galaxies  a galaxy is a large collection of billions of stars  our solar system is in the Milky Way galaxy.) **SPEC**

The universe contains many galaxies. Galaxies contain many stars, each star has a solar system. Our solar system is an a galaxy called the milky way.

1.33 explain that gravitational force:  causes moons to orbit planets  causes the planets to orbit the sun  causes artificial satellites to orbit the Earth  causes comets to orbit the sun

If an object is within the field of another objects gravitational force then it will travel around it in a path known as an orbit. In this way:

moons to orbit planets
the planets to orbit the sun
artificial satellites to orbit the Earth
comets to orbit the sun

1.35 use the relationship between orbital speed, orbital radius and time period

The first half of the equation works out the circumference of the circle, this is the distance, which is then divided by the time.

Orbital speed = 2× π ×orbital radius/ time period 

v = 2× π × r/ T

Key Equations for IGCSE Physics

Here I will be grouping together all the key equations for Physics IGCSE

Topic 1 - Forces and Motion

average speed = distance travelled/ time taken                             v = s/t

acceleration = change in velocity/ time taken                                a = (v-u)/t

force = mass x acceleration                                                           F = ma

weight = mass x gravitational field strength                                  w = mg

momentum = mass x velocity                                                        p = mv

moment = force x perpendicular distance from pivot                   moment = F x d

sum of anticlockwise moment = sum of clockwise moment

Topic 2 - Electricity

power = current x voltage                                                              p = I x V

energy = power x time                                                                   E = p x t

energy = current x voltage x time                                                  E = I x V x t

charge = current x time                                                                  Q = I x t

voltage = current x resistance                                                        V = I x R

Topic 3 - Waves

wave speed = frequency x wavelength                                          v = f x λ

law of reflection: angle of incidence = angle of reflection

law of refraction: refractive index,                                                  n = sin i/sin r                     (sin i = sin angle) of incidence, sin r = angle of refraction)

total internal reflection: refractive index,                                        n = 1/sin c

Topic 4 - Energy

efficiency = useful energy output from system/ total energy output into system x 100

work = force x distance                                                                   w = F x d    

GPE = mass x gravitational field strenght x height                         GPE = m x g x h

KE = ½ mass x speed²                                                                    KE = ½mv²

power = work done/ time taken                                                       P = W/t     

Topic 5 - Solids, Liquid and Gases

density = mass/ volume                                                                   p = m/v

pressure = force/ are                                                                        p  = F/A

pressure difference = height x density x gravity                              p = h x p x g  (in liquids)

pressure is proportional to absolute temperature                           P1/T1 = P2/T2

Topic 6 - Magnetism

input voltage/ output voltage = primary turns/ secondary turns     Vp/Vs = n1/n2

none in Topic 7 - Radioactivity