P2 F Revision Sheet E

GCSE UNIT P2 Living for the Future Revision folder

Exam questions on Physics will test everything on revision guide pg 98 to 111. Biology pg 62 to 79. Chemistry pg 82 to 95.

Space Pg 108:

Our Solar System

The Earth is a planet which moves round the Sun in a circle called an orbit. Other planets orbit the Sun too. They move in circles because the Sun’s gravity pulls them towards it. Jupiter Venus

Sun Sun

Saturn

Your anus!

Neptune

Pluto

Mars Mercury

Earth

planet

– – –

(Uranus)

Sun

comet

fires. a huge dust cloud which blocks sunlight and causes darkness for days or years. deaths of many plants and animals (maybe us!), killing off some species.

We know this has happened before because we can see old craters on Earth, and strange types of rocks containing elements which may have come from space. The name for the Sun and everything which orbits it (planets, moons, asteroids etc) is the Solar System. It is bigger than we can possibly imagine. It is so big that it is hard to find out what is really out there. We are discovering new things all the time, and learning more. Pg 109: We can do this by using telescopes, sending people out in spaceships, or sending robots and machines instead. We usually send spaceships without people (called unmanned spaceships) because it is so dangerous and difficult for humans to go into space (on manned spaceships.) Some problems are: – –

The planets are very far away and it takes years to get there. There is almost no gravity, which is bad for your health.

– – –

Lots of food is needed. It is very cold in space. There is no air, so you must take oxygen with you.

Robots do not need air or food, and can actually send back lots of pictures and information about temperature, magnetic fields, gravity and rock types. Pg 111:

Stars and Galaxies

I said that the Sun is huge and the Solar System is enormous, but it seems very small when you remember that the Sun is just a star (most stars are actually bigger). Some other stars have planets going round them (they have their own solar systems), some do not. Stars come in big groups called galaxies and the sun is a star in one of these groups. Most stars you can see at night are in our galaxy. There are billions of galaxies. The Universe is the name for all of this (absolutely everything). There is only one universe we know of (except on Doctor Who etc). Stars are originally made of gas which is pulled together by gravity until it lights up. After a long time, the hydrogen gas starts to run out though. When this happens, the star swells up. If it was originally a big star with lots of mass(stuff), there will be an explosion (a supernova) and then it will come back together. If it was really massive to start with it will then get squashed down smaller than a pinprick (a black hole) which has very strong gravity.

The Big Bang All the other galaxies we can see are moving away from us. This means that all galaxies are moving apart from each other and the total space between them is getting bigger and bigger. The whole universe must be expanding!. That means that a million years ago it was much smaller. In fact, in the beginning (billions of years ago) it was smaller than a pinprick. This tiny dot exploded and that was the start of everything. The explosion is called the big bang, and everything is still flying outwards from it today. Pg 107:The

Earth is a big Magnet

In the centre (core) of the Earth is a lot of iron. We think that this might be why the Earth has a magnetic field. Magnetism does not cause gravity, they are different forces.

We know Earth does have a magnetic field because compasses always point North (compasses are really just small floating magnets, so they turn to line up with the magnetic field). Luckily for us, the Earth’s magnetic field protects us from charged particles thrown out from the Sun in explosions called solar flares. Satellites are too far away to be properly protected, and they can be damaged by these particles (causing problems for mobile phones etc).

Energy and Electricity Pg 100

Coils and Magnets

There are different ways to make electricity, but it is usually done by moving a wire past a magnet. This idea is called the dynamo effect. In fact, it is much better to use a coil instead of just one wire, and to turn it round and round, so you can repeat the movement. You get more current by – using a stronger magnet. – making a coil with more turns (loops). – moving it faster. If you make electricity like this, the current goes backwards and forwards all the time. This is called alternating current (AC). If you use a battery instead, the current keeps going forward in one direction. This is called direct current (DC) Since it would be silly to generate electricity by someone winding a handle all the time, we have found different ways to turn magnets in coils of wire, for example.…

Pg 101 Fossil Fuel Power Station (coal, oil or gas) Burn coal (furnace)

Heat water to make steam (boiler)

Make the steam turn something (turbine)

Use this to turn a magnet in a coil (generator)

Take electricity to houses (National Grid)

Afterwards, there is lots of extra heat which cannot be used for electricity. It must be got rid of by making steam, which is let out through cooling towers. Lots of energy is lost as heat in all power stations. Not all of the energy in the fuel gets changed into electricity. Problem! Releases Carbon Dioxide (causes global warming) and some other nasty gasses . Pg 102 Nuclear Power Station Exactly the same, except the energy to heat the water comes from nuclear reactions in uranium fuel rods, not coal, oil or gas. One problem with this is dangerous left-over nuclear waste which must be put in a sealed container and buried carefully. The main advantage of nuclear power is that no Carbon Dioxide is made. Biomass Power Station (Wood, straw or animal dung (poo!) ) The power station works in the same way. Pg 99 Wind Turbine Uses wind to turn the big turbine, which turns the coil in the generator at the top of the tower. These do not cause air pollution, but take up lots of space, and only work in places where there is a steady wind . Wind is caused by the Sun’s heat. Pg 98,99

Solar Energy

We have used photocells in class to change light energy into electrical energy. They do not use coils and magnets. Photocells make direct current (DC) so the electricity flows in the same direction all the time. Sometimes you see big flat boards of photocells all joined together. This is called a solar panel. The bigger their area is, the more electricity they can make. Mirrors can be used to reflect even more sunlight onto the photocells. Photocells and wind turbines are good because they use an energy source which will never run out (the Sun). This means they use renewable energy. Also, they do not make Carbon Dioxide or other pollution, and you do not need to be connected to a National Grid to use them. However, they only work when it is not dark or when the wind is blowing steadily. You can also use solar energy to heat up water for your house without changing it to electricity. A black flat container of water on your roof, connected to pipes, can absorb the sunlight to heat water and is called a flat plate collector. The glass in a greenhouse or even a window can also trap the Sun’s heat in a room. This is called passive solar heating.

Pg 104

Paying for Electricity

The electricity company measures how much electricity you use. Anyone who uses electricity is called a consumer (like homes, schools and factories). The amount of electricity you use can be worked out like this: Power of your appliance (in kW) x number of hours you use it for = energy used (kWh) eg: 2kW x 4hours = 8kWh The electricity company tells you how many kilowatt hours (kWh) of energy you have used. One kWh costs about 10p, but it varies a bit. The total bill will be: Energy used (kWh) eg:

8

x

cost of 1 kWh (in p)

x

10p

= =

total cost 80p

Careful - Do not write £80 if you really mean 80p! Also, remember 1kW (kilowatt)= 1000W Note: Energy used is measured in kWh, (or joules). 1Kwh is much bigger than 1J

Nuclear Radiation Pg 105 Some materials give off nuclear radiation, these are called radioactive sources. There are three types of nuclear radiation: alpha, beta and gamma. Alpha is easily stopped, even by paper. Beta gets through paper but is stopped by 3mm (millimetres) of aluminium. Gamma gets through both of these but is stopped by a thick piece of lead. There is a tiny bit of radiation around us all the time, called background radiation which can come from rocks, space and living things, but it is not enough to hurt us. A high level of radiation could cause cancer. Pg 106 Radiation can also be useful though: Alpha is used for smoke detectors. Beta and gamma can be used in hospitals (a patient can be given a radioactive meal and then a special picture is taken of her body so that we can see where the meal has gone and check the body’s systems). This meal is called a tracer. Gamma can be used carefully to treat cancer. Whoever uses radioactive sources must protect themselves (take safety precautions): - Use tongs to hold sources away from the body. – Use them for a short time only. – Store them carefully in lead containers, clearly labelled. – Never look directly into a source.

Name __________________________

Starter Questions (Use the Information in this Folder) 1) Which planet is sixth from the Sun? 2) Which two things crashed and caused the moon to be created? 3) What is a comet made of? 4) Give two possible results of an asteroid hitting Earth.

5) Give an example of information an unmanned spaceship could send back to Earth. 6) What is a large group of stars called? 7) What is the name of the explosion which started everything? 8) We believe the Earth’s magnetic field is caused by a metal in the core. Which metal is the Earth’s core made of? 9) The dynamo effect is an idea that we can make an electric current by moving a ______________ near a _______________ 10) Name three types of fuel used in a power station.

11) Is the Sun a renewable source of energy? 12) My hairdryer has a power of 1500W and my TV has a power of 200W. If I use them both for an hour, which uses most electricity?

13) Give two precautions (safety rules) you should take when dealing with radioactive sources.

Moving on with physics revision…..

Name _____________________

The page numbers tell you where to find this information in your OCR revision guide.

1) pg 98. Lots of photocells joined together are called a ______________. Photocells produce DC current. What does DC stand for? What does it mean? 2) pg 100. A generator does not produce DC current. The current from a generator goes backwards and forwards all the time very quickly. What is the full name of this type of electric current? 3) pg 100. What happens if you keep moving a magnet near a coil of wire? 4) pg 99. What do we call the process of heating your house by trapping heat from the sun using glass? 5) pg 101. We send electricity long distances at HIGH VOLTAGE because that way we lose less energy in the wires. What is the name of the devices we use to change the voltage? 6) pg 102. We use a radioactive metal called uranium as fuel in nuclear power stations. Is uranium renewable? (renewable means it will never be used up and run out) 7) pg 104. a) A torch uses a voltage of 2V and a current of 4A. What power does it use? b) I have an ipod which uses a voltage of 3V and a current of 0.75A. What power does it use? c) Find the power of a radio using 6V and 0.5A. 8) pg 104 IMPORTANT! Electricity companies measure how much energy you have used. They measure it in kilowatt hours, also called “units.” a) I use a 1kW hairdryer for 2 hours. How many kWh have I used? _______________kW x ________________h = ______________kWh b) I use a 3kW fan heater for 3 hours. How much energy have I used? c) I use a 2.5kw oven for half an hour. How many units have I used?

d) You have heated your flat all evening and find you have used 6kWh in total. If 1kWh costs 10p, how much will you have to pay? 6kWh x 10p = ________________p e) How much does it cost to use 8kWh of electricity if 1 unit costs 12p? f) How much does it cost to use 24 units if electricity costs 13p per kWh?

g) I use a 2kW heating system for 5 hours. If electricity costs 14p per unit, how much does this cost? (Hint: The first step is to find out how many kWh are used)

9) pg 105. Draw a diagram to show which materials alpha, beta and gamma radiation will pass through (penetrate), and which would stop them.

10) pg 106. Give one use for each of the three types of nuclear radiation.

11) a) pg107. How was the moon created, according to the theory?

b) pg 108. The moon is a satellite (true/false). Which force stops the moon flying off away from the Earth? c) pg. 109. Why don’t we send many people into space? Give at least four reasons.

d) pg 110. What is an NEO? (give the full name and say what it actually is)

e) pg 111. What was the big bang?

So far so good. Now you have looked at all the main topics – Well done! Keep going though, there are more details to learn! Try these things…. Don’t forget space topics. They are at the back of the book, but you can look at them first. Look at the key words at the bottom of some pages. Use the ones in blue (for foundation paper). Find out where that word is used (it will be written in blue somewhere in that section) Make a list of keywords and what they mean. If you are stuck, ask. Do the questions on pg 112 and 113 (answers on pg 119) Test a friend. Explain it to your little sister or your Mum. Make up a question of your own for each page. Read part of a page carefully, then cover it up and write down everything you can remember. Make a poster or factsheet. Keep repeating the same stuff every few days; your brain will keep it in much better. The stuff in yellow boxes is for higher papers only. You will be tested on unit P2 (pages 98-111) REMEMBER – You can get good marks in this exam just by learning lots of facts. Good luck usually comes to people who are well prepared!