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Pages

1Where is Mars?2How long will it take to get to Mars?3Getting to Mars4How do rockets get off the ground?5Producing Thrust6What happens when rocket fuel burns?7Your mission to Mars!8Our need for oxygen9How oxygen gets to our cells10The effects of gravity11How low gravity affects bones12Preventing bones and muscles from becoming weak13Living and working in space14What do astronomers know about Mars?15A space-craft view of Mars16Exploring Mars17Energy for exploration18The rocky surface of Mars19More about the surface of Mars20The Martian atmosphere21The importance of water22The water cycle on Earth23Is there water on Mars?24Surviving on Mars25Your Martian home26Farming on Mars27Soil on Mars28Plants for Mars29Getting energy on Mars30Where will you go next?

Practicals

1Modelling the solar system in the school yard2Rocket Practical3Investigate the Energy in Fuels4Making a Telescope5What factors affect the output of a solar cell?6Modelling Diffusion7Examining Slides of Blood8What bones are like without calcium salts9Flame Test to Identify Metals10The Different States of Water11Water Purification for Human Consumption12Factors Affecting Germination13Solar Cells for Devices14Mars Bingo
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Rockets can use different types of fuel within their 'propulsion systems' to produce thrust, and one important fuel is hydrogen. Hydrogen fuel contains a large amount of energy.

1
What type of energy does a fuel like hydrogen contain?
chemical energy

Hydrogen is a gas at the temperature and pressure inside the room you are sitting in, but if it is cooled down and pressed very hard (compressed) it can become a liquid. Liquids usually take up less space than gases, and so inside rockets, hydrogen fuel is stored in liquid form.

1
What is the chemical formula for molecules of Hydrogen?
H
H2H
H3
H2

When a rocket is ready to be launched 'ignition' takes place. This is when the fuel is set alight, and allowed to burn. The burning involves a reaction with oxygen ('oxidation') which releases a huge amount of energy, and this pushes exhaust gases out of the tail end of the rocket down towards the Earth at very high speeds. These fast-moving exhaust gases propel the rocket off the ground.

1
What is the chemical formula for molecules of water?
H3O
H
H2
H2O
2
What is the chemical formula for molecules of oxygen?
O4
O
O2
O3
3
Do you know which chemical formulae equation describes how hydrogen and oxygen react together?
H + O2 → HO
H + O2 → H2O
H2 + O2 → H2O
4
Next, do you know which of the following describes a balanced equation for how hydrogen and oxygen react together?
H2 + O2 → 2H2O
H + O2 → HO
2H2 + O2 → 2H2O

Help with the above questions can be found at the BBC Bitesize Chemical Concepts page!

Investigate the Energy in Fuels

View Practical >
1
What sort of energy would be used by exhaust gases as they move?
kinetic energy
2
Which energy changes are involved in the combustion of rocket fuel?
chemical energy changes to kinetic energy, and also to heat and light energy
3
What happens when hydrogen reacts with oxygen?
water forms

1. Sankey diagrams are diagrams that can be used to represent energy changes like the change that occurs when rocket fuel burns. The width of arrows in the diagram is roughly proportional to the amount of energy of a particular sort, so the thicker the arrow, the more energy it represents. Drag the labels to the Sankey diagram below, so that it shows the energy changes when a rocket is launched.

100 000kJ of chemical energy in fuel is converted to 60 000kJ kinetic energy at rocket launch, plus 15 000kJ light energy and 25 000kJ heat energy