6 mark question: X-ray and infra-red hair removal devices!

This one is easier than it seems!
Basically you need to write about the dangers of x-rays and infra red…

• X-rays are higher frequency, ionising, can cause damage to cells/mutations/cancer etc. They are more dangerous than IR
• Infra-red is lower frequency, non-ionising, less dangerous but can cause overheating and burns
• But then need to draw a conclusion… is the IR device too risky full stop? Or is it safe for the specialist and maybe not the public? Training, regulation, safety?
• That last bit will get you the full marks!

This one could come up again, have a go, write yourself a model 6 mark answer… 

6 mark question: Evidence that supports the Big Bang Theory

How are you going to get 6 marks for this?

• I suggest you start by saying there are two important bits of evidence gained through observations of electromagnetic radiation that support the Big Bang Theory. 
• Red shift… how light from distant galaxies appears longer wavelength, so moving away, suggests that the universe is expanding which supports the theory that the universe was once very, very small and expanded in a "Big Bang"
• You also need to talk about CMB… microwave radiation observed from the whole of space, considered to be heat left over from the Big Bang etc.
• You need to have good SPAG 
• You need to have a go…

LDR and thermistor 6 mark question: Lily nailed it!

Topic 2: Controlling and using electric current

Charging by induction eg. balloon sticking to wall, comb and paperetc...

Can someone create a post that explains this nicely please. Copy and paste or a link is fine, own words is better!

1.8 Dangers of electrostatics (sparking, earthing etc...)

Check out this full explanation I found on a revision website...

 http://www.gcsescience.com/pse7-electrostatic-charge-spark-fuel-fire.htm

How can Fuel Flowing through a Pipe cause an Explosion?

Care must be taken to avoid sparks when putting fuel in
cars or aircraft. The fuel itself is an insulator (a hydrocarbon)
and charge can be transferred as the fuel flows through
a pipe if the pipe is also an insulator. The transfer of charge
happens because there is friction between the fuel and
the pipe. As the nozzle (the end) of the pipe is brought
close to the fuel tank, a spark can jump between the two
igniting the fuel. This can cause a serious explosion,
particularly with aircraft which are filled at a very high speed.

The spark can be avoided if the pipe nozzle
is made to conduct by connecting an earthing strap to it
and so any charge can be safely conducted away.
An earthing strap connects the pipe to the ground (the Earth).
In addition, a cable can connect the pipe to the fuel tank,
so that there can be no difference in charge between them.

There's also a nice animation on the BBC bitesize page...

http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/static_elec/staticact.shtml

LOs for Topic 1: Static and Current Electricity

I want you to look at this list and tell me... 

• the LOs you have learnt, 
• the ones you are happy with but now need to revise and 
• the bits you don't get at all.