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Year 9 Science Exam
January 2019
Revision Booklet
This booklet contains facts that you need to learn. You need to know
most of this booklet for your GCSE Science. If you learn it now it will give
you a head start!
Here are some suggestions for how to do it:
Start now! Don’t leave it until the last minute.
Tackle it one page at a time. You can’t learn it all at once.
Reorganise the information as a poster or a mind map.
Pick out key points and make your own, shorter notes that will be
easier to learn.
Break the information into chunks and write each on a card. Then
try to learn it one card at a time.
Pick a section, try to remember it, then try writing it out from
memory. Check what you wrote, correct your mistakes, and repeat!
Buddy up with a friend (or parent!) and test each other on one
section of the booklet.
Biology
Cells
An animal cell has:
Nucleus. This controls what the cell does.
Cytoplasm. This is a sort of jelly that fills the cell. It is where most chemical
reactions in the cell happen.
Cell membrane. This is a thin skin around the cell. It holds the cell together and
controls what goes in and out.
Mitochondria. These are where aerobic respiration happens.
Plant cells also have:
Cell wall: This is a stiff outer layer around the cell membrane. It supports the cell.
Vacuole: This is filled with cell sap. Cell sap is a liquid containing sugar and salts.
Chloroplasts: These are where photosynthesis happens.
Sperm cells
Sperm cells take the male DNA
to the egg.
A sperm cell has a tail to help it
swim to the egg.
It has a lot of mitochondria.
These provide energy for
swimming.
Diffusion
Diffusion is the spreading out of particles from an area of higher concentration to
an area of lower concentration.
Diffusion happens in solutions and gases. For example, the smell of perfume
diffuses through the air in a room.
The difference in concentration is called the concentration gradient. The bigger
the difference in concentration, the faster the diffusion rate.
A higher temperature will also give a faster diffusion rate. This is because the
particles have more energy, so move around faster.
Osmosis
Osmosis is the movement of water molecules across a partially permeable
membrane from a less concentrated solution to a more concentrated solution.
A partially permeable membrane is just one with very small holes in it.
Tiny molecules (like water) can pass through it, but bigger molecules can’t.
Overall, the water molecules moves from the less concentrated solution (where
there are lots of water molecules) to the more concentrated solution (where there
are fewer water molecules).
This means the more
concentrated solution
gets more dilute.
The water acts like it’s
trying to “even up” the
concentration on either
side of the membrane.
Water Sugar
Root hairs
Root hairs take in minerals and water from the soil.
Plant roots are covered in millions
of root hair cells.
These cells stick out into the soil
The “hairs” give the roots a large
surface area.
This is useful for absorbing water
and minerals from the soil.
Active transport
The concentration of minerals is usually higher in the root hair cells than in the
soil around them.
So root hair cells can’t use diffusion to take up minerals from the soil.
They use active transport instead.
Active transport allows the plant to absorb minerals from a very dilute solution in
the soil. It moves minerals against the concentration gradient.
But active transport needs energy from respiration to make it work.
Photosynthesis equation
Photosynthesis uses energy to change carbon dioxide and water into glucose
and oxygen.
It takes place in chloroplasts in plant cells.
Chloroplasts contain chlorophyll that absorbs light.
Energy is transferred to the chloroplasts from the environment by light.
Rate of photosynthesis
Pondweed can be used to measure the effect of light intensity on the rate of
photosynthesis.
1. The pondweed is placed in a beaker of water.
2. A ruler is used to measure a set distance from the pondweed
3. A light is placed at that distance. The pondweed in the beaker is left for 2 minutes
to acclimatise (get used to the new conditions).
4. Then the pondweed is left to photosynthesise for a set amount of time.
5. As it photosynthesises, oxygen is released. The number of oxygen bubbles
released are counted for an agreed amount of time and recorded in a results
table.
6. Steps 2-5 are repeated for at least 4 different distances.
7. The whole experiment is repeated twice more for each distance to get reliable
data.
Variables that must be controlled (kept the same) include:
the temperature of the water
the time the pondweed is left to photosynthesise
the time for which bubbles are counted
the amount of pondweed
the brightness of the lamp
Genetic engineering
The basic idea of genetic engineering is to transfer a gene for a desirable
characteristic from one organism’s DNA into another organism, so that it also has
the desirable characteristic.
1. A useful gene is cut from
one organism’s DNA
using enzymes.
2. The gene is inserted into
a vector, e.g. DNA from
a bacterial cell.
3. The vector is introduced
to the target organism,
e.g. the bacterial DNA is
put back into a bacterial
cell.
4. The target organism now
has the useful gene in its
DNA.
Immune response
We are given vaccinations containing dead or inactive pathogens to help protect us
against specific diseases.
At least one or even 2 vaccinations will be needed.
Shortly after the
vaccination the white
blood cells make
antibodies that help
destroy the invading
pathogens.
The more people that
are vaccinated, the
less chance there is
of someone catching
that disease, as they
are less likely to
come into contact
with anyone with the
symptoms.
2nd vaccination 1st vaccination
Chemistry
States of matter
State Diagram of
particles Arrangement of
particles
Relative distance between particles
Main movement of particles
Solid
Regular Very close Vibrate about fixed positions
Liquid
Random Close Move around each other
Gas
Random Far apart Move quickly in
all directions
State changes
1. Melting – Goes from a solid to a liquid
2. Evaporation – Goes from a liquid to a gas
3. Condensation – Goes from a gas to a liquid
4. Freezing – Goes from a liquid to a solid
Separation techniques
1. Filtration (e.g. sand and water)
Separates insoluble substances from soluble substances because particles of the
insoluble substance are too big to go through the filter paper
2. Crystallisation (e.g. salt dissolved in water)
Separates dissolved solid substances from a solvent by heating slowly so the
solvent evaporates and solid crystals form.
3. Simple distillation (e.g. salt dissolved in water)
Used when you want to purify a solvent, such as water that has salts dissolved
in it. The sample is heated so that it evaporates and then the solvent is collected
as it condenses.
4. Fractional distillation (e.g. crude oil)
Separates mixtures of lots of liquids that have different boiling points.
Periodic table
The periodic table contains elements.
Metals Non-metals
On the left-hand side On the right-hand side
Shiny Dull
High melting point Low melting points
Malleable and ductile Brittle
Good thermal conductors Poor thermal conductors
Good electrical conductors Poor electrical conductors
Chemical reactions
1. In a chemical reaction the total mass at the start of the reaction is the same as
the total mass at the end of the reaction.
This is known as conservation of mass.
2. The chemicals that you start with are called reactants.
The chemicals that are produced in the reaction are called products.
An equation for a chemical reaction is written using an arrow:
Reactants Products
3. Acids have a pH of 0 to 6.9
Alkalis have a pH of 7.1 to 14
A pH of 7.0 is neutral.
4. When acids react they make different salts:
Hydrochloric acid (HCl) → chloride
Sulfuric acid (H2SO4) → sulfate
5. Metal oxides, hydroxides and carbonates react with acids. These are the general
equations for these reactions.
metal oxide + acid → a salt + water
metal hydroxide + acid → a salt + water.
metal carbonate + acid → a salt + water + carbon dioxide
6. To make a salt from a metal oxide.
A. Add the metal oxide to the acid in excess (no more will dissolve)
B. Filter the solution to remove the excess base
C. Heat the solution to evaporate most of the water
D. Leave the solution to let the last of the water evaporate and allow crystals to
form
8. In some chemical reactions gases are formed. You can test for these by:
A. Hydrogen. Place a lit splint in the gas it will make a squeaky pop sound.
B. Oxygen. Place a glowing splint in the gas it will relight
C. Carbon dioxide. Bubble the gas through limewater, the limewater will go cloudy.
9. Combustion (burning) is an important chemical reaction. For a fuel to burn it
needs oxygen. The chemical equation for combustion is
Fuel + Oxygen Carbon Dioxide + Water
Physics
Space
The Solar System
Everything in the solar system orbits the Sun.
The order of the planets is:
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
Stars, galaxies and the Universe
The Sun is a star.
Galaxies are groups of billions of stars.
Our galaxy is called the Milky Way.
The Universe is made up of billions of galaxies.
Light years
A light year is the distance travelled by light in one year.
Gravity
All objects attract other objects due to the force of gravity.
There is gravity everywhere, even in space.
Gravity gets weaker as you move away from a planet, but never disappears
entirely.
The strength of gravity is called ‘g’ (gravitational field strength).
The value of ‘g’ is different on different planets.
On Earth, g is about 9.8 N/kg.
Days, years and seasons
Day Caused by the rotation of the Earth, every 24 hours.
It is daylight when our side of the Earth faces the Sun.
Year Caused by the Earth orbiting the Sun, every 365.25 days.
Seasons
Caused by the tilt of the Earth’s axis.
In summer we are tilted towards the Sun. We have longer days
and the Sun is higher in the sky, so it is warmer.
Energy
Energy cannot be created or destroyed, only transferred between different forms.
Energy store Stored by…
Kinetic … any moving object.
Chemical … food, fossil fuels, batteries.
Nuclear … fuel used in nuclear power stations (e.g. uranium).
Gravitational … any object that has been lifted up.
Elastic … any object that has been squashed or stretched.
Thermal … a hot object.
Energy transfer Transferred …
Light … by a light wave.
Sound … by a sound wave.
Electrical … by an electric circuit.
Thermal … from a hot to a cold object.
Mechanical … by a force acting on a moving object.
Energy Resources
Renewable energy resources will never run out.
Renewable Non-renewable
Wind Wave Solar Tidal
Hydroelectric Biomass
Geothermal
Coal Oil
Gas Nuclear
Forces
All forces are measured in newtons (N)
Weight Force of gravity pulling you down.
Upthrust Force that makes you float in air or water.
Reaction
force Force that supports you on your chair.
Tension Force in a tight string or elastic band that stops it stretching any
further.
Friction Force when two surfaces rub. Makes it harder for things to move.
Balanced forces
If two equal forces act in opposite directions, then the forces are balanced.
If an object is not moving, the forces must be balanced.
If an object is moving at a constant speed, the forces must also be balanced.
Unbalanced forces
If the forces on an object are unbalanced, then it must be doing one of these things:
• Changing speed (speeding up or slowing down
• Changing direction
Resultant force
Resultant force is the total or overall force on an object.
This hedgehog has… 200 N + 150 N = 350 N force to the right
50 N force to the left
So the resultant force is 350 N - 50 N = 300 N to the right
200 N
150 N 50 N
Electricity
Circuit symbols
Cell Switch Ammeter Voltmeter
Light bulb Motor Resistor
Waves
Oscilloscope traces of sound waves
low, quiet low, loud high, loud
Amplitude: The height of the traces tells you how loud the sound is.
Frequency: The number of vibrations in one second.
It is measured in hertz (Hz).
Closer together waves means higher frequency.
Longitudinal wave
Vibration is parallel to
the direction of travel
Transverse wave
Vibration is at right
angles to the direction of
travel
Equations
energy = power × time E = P × t
work done = force × distance moved W = F × d
force = mass × acceleration F = m × a
distance = speed × time d = s × t
voltage = current × resistance V = I × R
wave speed = frequency × wavelength v = f × λ
weight = mass × gravitational field strength W = m × g
Units
Quantity Unit name Unit symbol
energy or work done joules J
power watts W
time seconds s
force (including weight) newtons N
distance or wavelength metres m
speed metres per second m/s
voltage volts V
current amps A
resistance ohms Ω
frequency hertz Hz
mass kilograms kg
acceleration metres per second squared m/s2
gravitational field strength newtons per kilogram N/kg
Unit Prefixes
Prefix Name Value d deci 10-1
T tera 1012 c centi 10-2
G giga 109 m milli 10-3
M mega 106 μ micro 10-6
k kilo 103 n nano 10-9
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