Right. So my mother says the world is round. In that case,

[Flightattendant2]

why do the people on the bottom, not feel like the blood is rushing to their heads?

I need to explain this one to ds because me and mum ended up concluding that the earth is actually flat.

For all you know YOU are at the bottom and us in Australia are at the top ...

Like others have said, in the vacuum of the universe there is no 'top' and 'bottom'.
Gravity stops us from floating away.

Thus ends Prof. ghosty's physics lesson.

PS - I wasn't allowed to do Physics O Level as I was so CRAP at it

Bubbaluv, 'hard for a child to grasp'

Yes but I'm 35!!

Thanks all for trying. i still think it's flat.

To be a real pedant (and risk getting sand kicked in my face), the world isn't round at all; it's an oblate spheroid.

We still haven't managed to convice FA2 that it's not flat, I think geometric pedantry is better left until we at least move her on from the middle-ages.

Thank you for that you YKNOTC ... was racking my brain for the correct term (as the earth is not round) ...

This is the West Wing scene - its fab!

yes, but if it's flat then what's under it? and wouldn't we fall off the egde?

4 elephants and a giant turtle...

An Oblate what?

What's under it?

nobody knows

Unless it's the Australians. I mean if they can hold on to the bottom of a circle they can hold on to the bottom of a plate. Yes?

Middle ages my arse

There isn't an edge btw. It just goes on for ever.
Actually there are some places called Edge. Alderley edge.

There you go. It's in Cheshire.

No-where is top or botton, the force of gravity pulls everyone into the centre.

and it is an oblate spheroid (sligtly squashed ball shape, to those of us in the cheap seats)

I prefer the idea of a wobblate spheroid.

That describes me perfectly!

and gravity acts between all items that have mass.

You are being attracted to the computer, (and contrarywise), but not by much because neither you, nor the computer are that large. the earth is large to the force of attraction between it and us is far larger.

If my arse gets much bigger I will have a substantial gravitational field myself....

MB, I may spend a lot of time with my computer, but I should assure you that we are Just Good Friends

Ahh, you say that now......

Thanks MB. But even though neither side is the top, as such, and it spins and so forth, surely by its very nature an object has a top and a bottom at any given moment?

So when it's our turn to be underneath, why don't we feel upside down?

Say we got hold of a giant air balloon that had a big magnet in the middle and we walked under it, feet attached to it by 'gravity' - we would be being pulled towards it, but we would still be upside down. So why don't we feel upside down on the earth?

Come to think of it why don't we feel it spinning too?

We spin on an axis but from side to side IYSWIM

like [[http://www.dkimages.com/discover/previews/939/65030615.JPG here]

We don't feel it spinning, beacuse it is there all the time, and the body stops taking notice of things that are there all the time....think of getting used to the smell of a perfume, after a while you don't notice it

We don't 'feel' the tonnes of gases in the atmosphere that are pressing on our headseither!

Oh Ok. I am just going to have to accept that I think! (can you tell that my science teachers hated me??!!)

I am a bit scared about the tonnes of gases now.

Thankyou for explaining.

Don't worry about the tonnes of gases, millions of years of evolution have arrived at a skull that is wonderful at coping with it!

Lol
Thanks. I hope one day to get my head around some of this stuff.

Pretty good thing Ds is going to school in a few weeks really!

Good questions Flightattendant2, I think there is actually a scientist inside you trying to get out!

The person in your balloon experiment feels upside down because his head is nearer the ground (the surface of the earth, not the balloon) than his feet. That is what 'upside down' means (to anyone under the influence of the earth's gravity).

Wherever you are standing on the earth, your feet will always be nearer the ground than your head, so you never feel upside down.

Now, why don't we feel it spinning is a much more interesting question. And the answer is not because we are used to it (if that was all it was, if we turned round we would be able to notice the change from spinning backwards to spinning forwards). It is because the earth only rotates once every 24 hours. If you sat on a roundabout that went that slowly, you wouldn't notice that either!

Ooh! The upside down thing is starting to make sense...sort of...but the spinning thing, I always thought we were taught that it is actually very fast.
So, how fast are we moving, relatively, to get round back to here in 24hours?

There is no scientist in me, unless he was really really naughty in a former life and is being punished by being stuck within a complete numpty!

The earth is flat. It's all a conspiracy. Teach the controversy.

I knew I wasn't alone...

MrVibrating, we don't feel the earth's rotation because it's constant, not because it's slow. If it suddenly sped up or slowed down we'd feel it; we'd all fall over or fly off or something