Useful Websites:

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/bitesize/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/SeriesDownloads.aspx?Level1=Primary,Secondary&SeriesTitle=Collins%20Revision&rt=Videos 3. Test yourself using Doc Brown’s quizzes. Be sure you test yourself on the test relevant to your year! http://www.docbrown.info/ks3science.htm

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 can’t make them in our lifetime (they will run out). • Renewable energy resources • Examples of renewable energy resources are: • solar power • wind power • tidal power • wave power • hydroelectric power • geothermal power • biomass • They are renewable because they will not run out like fossil fuels will in our lifetime. 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 Wave Energy Uses kinetic energy in waves to generate electricity Tidal Energy Uses the gravitational potential energy in tides 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 won’t 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 don’t 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 don’t need them, recycling aluminium cans.

3. Acids and Alkalis Hazard Symbols h i 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 it’s 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 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 • 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) Circulatory System Digestive System 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