Scientists out there - can you please explain some complex things in simple terms to me?

[Tinker]

Inspired by ks's GCSE thread yesterday, I often stumble on really basic concepts and wondered if anyone could help, in a Pass Notes, style with some theories

String theory - simple explanation

E=MC2 - what would you say to your child if they asked about it?

My current favourite - magnetic pole swap/shift?. We're supposed to be well overdue for this. What will happen if/when it does happen? Is it instantaneous? Is it gradual? Is it the end of life on earth ( suspect it might be )

Anyone help? Anyone have other questions for our MN experts?

This any good?

Gosh, thanks lou. Not sure whether I should have read that - feel rather disturbed!

I saw a programme on polar shifts and its happening right nowm but very gradually. One of the biggest consequences is the fact for a while the poles will not be magentic meaning an increase in solar radiation and a slight rise in cancer rates - but according to the programme nothing to worry about. and they don't think it will be the end for life!

Or have a look at this one for general queries

HTH

I remember this from school so hope it's not too vague -
C = the speed of light
C2 = the speed of light squared - i.e. very fast
M = Mass - i.e. any item with physical size.
E = energy.
The equations basically means that if any object is moved fast enough (i.e. the speed of light squared) then it will become pure energy and will no longer be a physical object.

eefs - that's great. Is it a co-incidence it's the speed of light squared? Thinking aloud really.

Nome - I've saved that site,will look properly later, thanks

For you Ks .

no, it's no coincidence, it's to do with the fact that light is also a form of energy.
BTW - this is impossible to do in real life - it's a formula that's really only relevant to radiation energy of an electron moving in the electro-magnetic field, but theoretically it can be applied to bigger items and means that if a small object, say a pea, could be moved that fast it would create a huge amount of energy.
If you ever want to invent an invisibility machine then this is the formula you'd need - let us know when it's ready

Now the string theory - this is my understanding, so correct me if I'm wrong: previously people thought that everything was composed of atoms - i.e. atoms were the smallest thing. Then it was discovered that atoms consist of electrons whizzing around a nucleus. The nucleus consisted of protons and neutrons. It was then discovered that protons and neutrons were made up of quarks. So it was though that quarks and electrons were smallest breakdown possible and that they were solid items i.e. they had no further internal substructure. This oversimplified things and caused the two main bodies of physics - quantum mechanics and general relativity to be incompatable with each other. i.e. both theories were both correct but if compared with eachother they stated different things and therefore could not both be correct.... However if the quarks and electrons are considered to be composed of string-like structures as opposed to solid dot's then both theories are finally compatable. The string theory basically solved lots of problems scientists had and is sometimes called the theory of everything i.e. the ultimate explanation of the universe at its most microscopic level.

I'd never heard of the pole swap though - it's a bit unnerving isn't it!

eefs - good stuff, pretty much my understanding of string theory (after seeing programme about it, not my own philosophical musings )

Another question - can 'they' manufacture water since 'they' know the formula for it?

I thought that E=MC2 also meant that the energy present in a body (if you could liberate it all, which we can't) is equal to its mass times the speed of light suared, ie a LOT* of energy.

Tinker, you can make water by reacting hydrogen and oxygen together!

You can also get it when you burn glucose (and all other starches) via the reaction

Glucose + oxygen .......> Water + carbon dioxide

That is what our cells do when we break down glucose for energy, we take in the oxygen we need when we breath and we breath out the carbon dixide and water.....it is why your breath clouds when it is cold, the water vapour is tauning back into tiny droplets of liquid!

Thanks hmb but can it be made in huge quantities?

It can, but it takes so much energy it isn't worth it! It is easier to purify the water we already have.
The Glucose would probably be made from sugar beet ot cane sugar and that will not grow without..........water! So if you have enough water to grow the crops you dont need to make it by buring carbohydrates. Mind you that sort of Biomass fuel is renewable, unlike burning coal etc (which also produce CO2 and H2O)

Oh, just had a chat with my DH re E=MC2

Basically the amount of energy in something is equal to it's mass in Kilograms times the spped of light squared.

The speed of light is 300000000 Meters a second

The speed of light squared is 90000000000000000 Meters a second.

So if you converted all the mass in 1 KG of flour into the energy it contains it would be
90,000,000,000,000,000 Joules. The avarage dietart intake of a UK woman each day is 7,030,000 Joules.

So if we could liberate all the energy in a bag of flour it would feed a single woman for 12,802,275,960 days or 35,074,728 years! (if my sums are correct) Amazing stuff!

When atom bombs are exploded a small fraction of their mass is converted into energy, a huge explosion but only a fraction of the energy contained in the nuclear material

I think string theory is in this weeks new scientist- they're articles are usually fairly readable

They can manufacture water - thats the reaction that flies space rockets into space, but its very costly in terms of energy and difficult to do. And you need the basic ingredients - hydrogen and oxygen. Why would you want to make water - its plentiful if not drinkable!

Right, I have another one if anyone can help. Fermat's Last Theorem. What's that all about then? I know it's been solved/proved but, what then? What's been proved? What does it do/show?

Thanks

Have a look at

www-gap.dcs.st-and.ac.uk/~history/HistTopics/Fermat's_last_theorem.html

for the history. The maths is way beyond me!

The basics are that the square on the hypotenuse is equal to the sum of the squares of the two opposite sides (for a right angled triangle), but that this doesn't hold true for the cube, 4th 5th power etc.