h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

i need some help, i cant understand why i feel that i am heavy, i am 65kg so my 65kg * gravity is what i am expiercing in the down pull to earth, but that force is been returned to me by the earth (newtons third law) so why arnt i nearly waitless?

It works the same way as when you push on a brick wall. The wall doesn't move because you are pushing at the same force it is pushing at you. However that doesn't mean that your push is nothing...

You aren't weightless because gravity acts inwards on the earth. Therefore there is no opposing gravitational force against you.

Because you only feel the weight of yourself when you are moving or doing something.

If you stood perfectly still and closed your eyes than you (should) have no sensation of weight - you would feel exactly the same in outer space, stood on the moon, or whatever. Once you start moving about, however, you are using your leg muscles to create a force against the ground and the weight that you feel is the opposing equilibrium force of gravity.

B

Are you reading Bill Bryson's book at the moment?

Is that any good? I keep considering buying it, but don't know whether it'd be a bit simplistic for a scientist.



B

Master B you are soooo up yourself sometimes
What about for a Alevel student...?



I stood still and i still felt heavy...well...8stone heavy...

It's excellent. I think there's probably enough in it to keep scientists interested.

Teachers could certainly use some of the stuff to spice up their lessons! Giving credit where due, of course.

**pointedly ignores Kat **

Well, that was certainly part of my thinking, although I do read a huge amount of pop-science myself.

Possibly my main issue with teaching will be straying off the lesson plan to share some fascinating bit of information last night with the class...

B

So are you a teacher then? or are you going to be? well sugestion, make it fun, i have a science teacher who is always telling jokes and stuff, i like him the most.

But if you can capture their interest......

This country needs 'inspirational' teachers!

Hey come on Master B! I'll have you as a teacher any day because whenever I come across you you're being nice and great! You often remind me of a physics teacher in my school!
He makes physics actually interesting and can explain it to a 6 year old. I think that's probably the key. If you can explain it to a 6 year old and then build it up then you're sorted.

theres a point, what are you going to teach? i know i would love it if a teacher where to talks about the quantum theory, but lets see any other 14-15 year old in my school apart from me understand what the hell hes talking about

Being a teacher under a labour government doesn't mean I have to like T*ny B*air, you know. I just like the £6000 he's giving me to train.

The key word, as far as I'm concerned, is 'enthusiasm'. I love my subject, as Inifinte's teacher obviously does, and that sort of thing rubs off on kids. They claim to be cool, but the vast majority of them are as impressionable as Play-Dough.

B

*simulpost*

Ooh - simulposts. I'm going to be a science teacher, infinite. Mostly Chemistry, but I'll be expected to teach across the range of sciences, due to the dozy curriculum we have here in the UK.

And thanks Kat! It's nice to know someone's got something inspiring to say about teachers.

B

The sensation of an "observer" in a gravitational field is the same as that in an acceleration (say, an upwardly accelerating lift). Forget 3rd law for a moment. If you're in a closed lift, you can't tell whether or not you're in a G-field standing still, or in no field but accelerating upward. Actually, there is a difference (the G-field having spherical divergence but that is not discernable with a local observation). You feel it, if you do, because dynamics are affected by the acceleration. Now, back to the 3rd law. Gravity pulls you to the floor. The floor responds by pushing back. In fact, far from nullifying the effect you feel, it is, qualitatively, doubled.

oh yeah. thats right, i started this thread asking a question about newtons third law, but now we are talking about teachers, how unlike people on hootoo



i would love to see teachers just introdusing students to things like the quantum world, nobody knows about it, nobody knows a particle can be in places at the same time unless viewed, and when i tell someone, they are interested. why dont teachers show students thing like this to get them interested in phyics, the first bit of phyics i did was on work with ramps and pulleys etc, most students took a dislike to it very quickly.

I didn't really understand that I'm afraid. Can you explain in small person terms?

the g-force thing...

Why do we still talk about Newton when he was superceded by Einstein