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Medium
The Sun
The Hubble Space telescope
The Space race from 1957 to 1975
Constellations
The Northern Lights
Galaxies
How stars were used to navigate in the olden days
The European Space Agency
The Asteroid belt
Halley’s comet
The possibility of life on other planets
Space travel

Hard
Copernicus, Galileo and the conflict of science and religion
The history of space investigation
Black Holes
The life of stars
Technology invented for space exploration that is now used in everyday life
Superstitions related to the stars
The science of space travel in movies

7A Cells Summary
7B Reproduction Summary

The descriptions you need are as follows.

Current - The FLOW of electrical CHARGE(ya know like positive or negative - actually negative in this case - it’s electrons and they’re negative - this answers your conventional current question too - they thought it was the positive charges that went round - that’s the same as a negative charge going in the opposite direction - two negatives make a positive right!)

The important point here is the FLOW bit. It the electrons don’t move then there’s no current. Only charge.

Currents of only 0.7A are all that’s needed to kill a human being.

Current on it’s own isn’t the end of the story though. Current causes transfer of energy from one place to another (cos it moves) and we can see it’s effect if we heat stuff up, like pencils (attach one to a power pack if your teacher lets you it’s very cool - this video is not bad, but I do it much better)

Voltage is needed to push the stuff around. Think of it as the push, like the charge sits on a hill and the voltage is the steepness of that hill.

That’s where the word “Potential DIFFERENCE” comes in.

You see the voltage is like the difference between the height of the top of the hill and the bottom.

So if the charge is a ball and it sits on a flat surface (no difference in POTENTIAL) then there’s no VOLTAGE - i.e. there’s no PUSH on it to get the thing moving.

When there’s a potential difference i.e. voltage then the thing will start moving.

THAT’S why we put a voltmeter ACROSS in parallel to the thing we’re measuring. Cos you’re tryint to stand back and see the steepness of the hill and you can only see that by taking the DIFFERENCE at two points.

Whereas the current is measured in Series because that is going THROUGH the ammeter. It’s like counting tennis balls coming past a point.

So -

Voltage = shocks
Current = Heating

High current = danger of burns
High Voltage - danger of shocks
High current + High Voltage = danger of death

Make sense now?

This was the result of electrons jumping across from a charged person to a Bunsen burner, when the person has a very high voltage on them. The current is really small (there’s only a small spark) so the man is perfectly safe.

Remember - voltage gives you shocks and current causes heating!

Oh and just in case you’re wondering what high voltage AND high current looks like…

Year 11 have been studying organic chemistry and how to represent the structure of a molecule using a displayed formula.

Here’s a picture of someone who likes his chemistry a little too much and had the displayed formula of the sedative diazepam tattooed on his arm.