2. Download short revision clips to your computer or mobile phone from the following website: Be sure you use the clips relevant to your year!

1

• Year 7 Science Revision
• The topics that you will tested on on Monday 2nd
  December are
• Energy resources
• Acids and alkalis
• Cells, tissues and organ systems
• Revision is very important if you want to achieve
  your best. Our memory works by constantly using
  information. Revising means we are using the
  information.

Useful Websites
1. The BBC bitesize website has lots of
information, activities and quizzes for you to
revise from. Remember to choose the topics you
have covered in year 7! http//www.bbc.co.uk/bites
ize/ks3/science/
2. Download short revision clips to your computer
or mobile phone from the following website Be
sure you use the clips relevant to your year!
http//www.collinseducation.com/Downloads/Pages/Se
riesDownloads.aspx?Level1Primary,SecondarySeries
TitleCollins20RevisionrtVideos
3. Test yourself using Doc Browns quizzes. Be
sure you test yourself on the test relevant to
your year! http//www.docbrown.info/ks3science.ht
m
2
Energy Resources

• Energy Resources
• Non- renewable energy
• Also know as fossil fuels.
• Examples of fossil fuels
• coal
• oil
• gas
• They are non-renewable because they have taken
  millions of year to make and we cant make them
  in our lifetime (they will run out).
• Renewable energy resources
• Examples of renewable energy resources are
• solar power
• wind power
• tidal power

Energy Resources and the environment
Biomass Uses the chemical energy in living things
to generate electricity
Geothermal Energy Uses the heat energy in the
Earth to generate electricity
Tidal Energy Uses the gravitational potential
energy in tides to generate electricity
Wave Energy Uses kinetic energy in waves to
generate electricity
no special equipment needed so can used in
poorer countries - Large areas of land are needed
to grow enough trees
no pollution - Found in very few places in the
world
no pollution - Needs lots of machines to get
enough energy, look ugly
reliable as always two tides a day - Costs a
lot to build a local dam, could cause flooding
Hydroelectric Energy Uses flowing water (kinetic
energy) to generate electricity
Wind Energy Uses the wind (kinetic energy) to
generate electricity
Solar Energy Uses the sun (heat energy) to
generate electricity or heat up water
Nuclear Energy Uses the chemical energy in metals
to generate electricity
no pollution, renewable (the sun wont run out
any time soon!) - expensive, only works if sunny!
no pollution, quite cheap and easy to build -
Some people think they are ugly, only works if
windy!
no harmful gases produced - non-renewable
(uranium will run out), produces dangerous
radioactive waste
no pollution - Costs a lot of money to build a
dam
Recycling, Reusing, Reducing Recycling, reusing,
reducing helps the environment because it means
new objects dont have to be made using energy
resources. This can reduce pollution. Examples
of what you could do are using reusing plastic
bags, turning lights off when you dont need
them, recycling aluminium cans.
3
Acids and Alkalis
Hazard Symbols
Acids and alkalis are corrosive and have to be
used carefully. Scientists use hazard symbols to
help know about the dangers of chemicals.

• Acids
• Acids contain the element hydrogen (H).
• Examples of acids in the home are vinegar,
  oranges and grapefruits.
• Examples of acids in the science laboratory are
  hydrochloric acid and sulphuric acid.

• Alkalis
• Alkalis contain a hydroxide (OH -oxygen and
  hydrogen).
• Examples of alkalis in the home are soaps, oven
  cleaners and washing powders.
• Examples of alkalis in the science laboratory
  are sodium hydroxide, potassium hydroxide.

Irritant can cause reddening and blistering of
the skin
Corrosive attacks and destroys living tissues
Highly flammable easily catches fire
Indicators Indictors are used to say whether
liquids or solutions are acidic, neutral or
alkaline
Litmus paper Litmus paper is an indicator. If in
a neutral solution its colour is unchanged, it
turns red in an acidic solution and blue in an
alkaline solution.
Toxic - Can cause death
Oxidising provides oxygen to make other
substances burn
Harmful e.g. when swallowed, breathed in
pH scale
Environmental hazard substance that is
dangerous to the environment
Radiation possibly causing DNA damage
Explosive substance that can explode

• Neutralisation
• Reactions between acids and alkalis are called
  neutralisation reactions. We use neutralisation
  reactions to help us
• Indigestion tablets to reduce excess stomach
  acid
• Farmers add lime (alkali) to soil to neutralise
  excess acidity from acid rain.
• Toothpaste (alkali) neutralises acid that builds
  up on our teeth.

Universal indicator can be used to measure how
strong or weak an acid or alkali is (this means
it gives more information than Litmus paper).
Universal indicator is a mixture of several dyes
extracted from plants. The overall colour the
indicator solution is compared with the range of
colours in the pH scale (above). A neutral
solution has a pH of 7. An acidic solution has a
pH of 1 to 6 (strong acid 1 to 3, weak acid 4
to 6). An alkaline solution has a pH of 8 to 14
(weak alkali 8 to 10, strong alkali 11 to 14).
4
Cells
Animal and plant cells
Specialised Cells
Cell
Function
Adaptation
Absorbs and carries oxygen around the body
Large cell membrane surface area
Red blood cell
Carries messages around the body
Long and thin
Nerve cell
Functions of animal and plant cell parts
Develops into an embryo
Large and contains lots of cytoplasm
Part Function (job) Found in animal cells Found in plant cells
Cell membrane Controls what passes into and out of the cell ? ?
Nucleus Contain the genetic material and control the cell activities ? ?
Cytoplasm Jelly-like liquid where important chemical reaction take place ? ?
Cell wall Made of cellulose and supports the cell, helping it keep its shape ?
Vacuole Contains cell sap ?
Chloroplasts Contain chlorophyll which traps light for use in photosynthesis (where plants make their own food) ?
Egg cell
Fertilise the egg
Has a long tail allowing it to move
Sperm cell
Large cell membrane surface area
Absorb water
Root hair cell
Site of photosynthesis
Contains lot of chloroplasts
Palisade cell
5
Tissues, Organs, Systems
Organ Systems An organ system is made from a
group of different organs, which all work
together to do a particular job.
Tissues
Circulatory System
Digestive System

• Animal cells and plant cells can form tissues,
  like muscle tissue. A living tissue is made from
  a group of cells with a similar structure and
  function, which all work together to do a
  particular job.
• Here are some examples of tissues
• muscle
• the lining of the intestine
• the lining of the lungs
• phloem (tubes that carry dissolved sugar around
  a plant)
• root hair tissue (for plants to take up water
  and minerals from the soil)

heart
capillaries
Job To transport blood and substances around the
body.
Job To break food we eat into smaller pieces so
that we can absorb it into our blood.
Respiratory System
Nervous System

• Organs
• An organ is made from a group of different
  tissues, which all work together to do a
  particular job.
• Here are some examples of organs
• heart
• lung
• stomach
• brain
• leaf
• root

Contains nose, trachea, lungs, bronchus,
bronchioles and alveoli Job To bring oxygen into
your body, and remove the carbon dioxide from
your body.
Contains nerves, brain, spinal cord. Job To
carry messages to difference part of the body