Exam: 07/06/11

Thrust- this is the force produced by the rocket engine. it lifts the rocket off the ground and moves it upwards. It causes an increase in the momentum of the rocket.

Weight- the earths gravity pulls the rocket towards the ground.

Air resistance- this force is caused by moving through the air. the faster the rocket goes the greater the air resistance. Air resistance always act as a counter force to the motion.

The central nervous system has two major parts. One of these is the brain.

The brain contains the cerebral cortex and the cerebellum. They do different things

• the cerebral cortex is involved in intelligence, memory, language and consciousness.
• the cerebellum regulates basic processes such as balance, heartbeat and breathing.

Researchers have found that these two areas change by different amounts as a person gets older

• the cerebral cotrex undergoes many changes with age
• the cerebellum undergoes fewer changes with age  

Did you know that your mobile phone contains about 4g of copper?

The battery contains lithium and the casing is made from aluminium. Other metals such as iron and zinc are in the components inside. All of these metals are extracted from ores-some by heating with carbon, some by electrolysis. These metal ores are fast running out. the price of copper has rocketed up- in 2008, copper cost four times as much as it did five years earlier. Ores with lower and lower percentages of copper are being mined as the ores with copper in them are running out.

Extracting copper

After mining, the ore is seperated from the waste rock. The ore is processed to make copper. Two methods of making copper are the 'blister' process and the 'electrolysis' process. Both of these methods use large amounts of energy, but the energy inputs are used for different reasons.

So why does copper end up in your mobile phone?

Well, after it has been purified, copper is an excellent electrical conductor. Copper has many other properties that makeit useful for other things from water pipes to jewellery. That is why it is in such high demand. Although it has been extracted for thousands of years, 95% of the total extraction of copper has been carried out in the last 100 years, and we are running out of fresh supplies fast!

So if you want to keep usin mobile phones, think about how you dispose of your old one- we need to make sure as much copper as possible is recycled so that we dont run out too fast.