https://www.youtube.com/watch?feature=player_embedded&v=1Xp_imnO6WE#t=0

1 – something to go with mass and friction. The heavy end has more mass so it weighs down harder on the finger underneath resulting in more friction. Thus the heavy end doesn’t slide as far as the lighter end.

2 – don’t know

3 – don’t know

actually I don’t know the rest of them.

4. is easy ….
   To get a certain amount of iron into cereal they actually add tiny little flecks of iron into the food.

Yes really!
To check it out, get a full box of cereal, a powerful magnet, give the cereal a good shake with the magnet up against the bag and if you look carefully you’ll see those tiny little flecks of iron stuck to where the magnet is on the side of the bag.

1. - I agree with P_P’s explanation.

2. - When you flip a phone, you always impart motion in two axis (You always get some sort of twist) Two of the axis of rotation are stable and any minimal second axis rotation is unable to affect it.

3. Static electricity attracts lots of things, not sure why water should be any different.

4. +1 Bill

5. - Inertial vertical air movement from the fire lifts the remnants of the teabag.

Carmen_Sandiego said:

5. - Inertial vertical air movement from the fire lifts the remnants of the teabag.

CS just used fancier words for what I was thinking.

Nice video.

Would have liked to go and see Chris Hadfield, but he’s sold out in Sydney (still selling in Canberra though).

I think 1 and 5 are fairly straightforward, although I’m still surprised that 1 works so well.

I’ll take Bill’s word for it on 4.

I think 2 and 3 need more discussion.

C-S’s explanation for 2 may be correct, but I don’t follow it. What is special about rotation about one of the three axes that makes it less stable than the other two?

With 3, I think the point is that the electrostatic force between a charged surface (like the plastic cup) and a neutral surface (like he says the water is) is too small to account for the deflection you get in the water.

Haven’t read the comments to the video yet.

The Rev Dodgson said:

Nice video.

Would have liked to go and see Chris Hadfield, but he’s sold out in Sydney (still selling in Canberra though).

I think 1 and 5 are fairly straightforward, although I’m still surprised that 1 works so well.

I’ll take Bill’s word for it on 4.

I think 2 and 3 need more discussion.

C-S’s explanation for 2 may be correct, but I don’t follow it. What is special about rotation about one of the three axes that makes it less stable than the other two?

With 3, I think the point is that the electrostatic force between a charged surface (like the plastic cup) and a neutral surface (like he says the water is) is too small to account for the deflection you get in the water.

Haven’t read the comments to the video yet.

I can’t even see the video but I’d ask that if the electrostatcic force is too small to deflect the water, could it be assisted by changes in air flow?

roughbarked said:

I can’t even see the video but I’d ask that if the electrostatcic force is too small to deflect the water, could it be assisted by changes in air flow?

I wondered that as well, but I don’t really see why you would get an air flow.

The Rev Dodgson said:

roughbarked said:

I can’t even see the video but I’d ask that if the electrostatcic force is too small to deflect the water, could it be assisted by changes in air flow?

I wondered that as well, but I don’t really see why you would get an air flow.

Since I cannot see the video or know of the controls in the experiment, i can only assume that as the cup comes closer to the water the air flow is reduced to the point where the attraction can become greater.

roughbarked said:

The Rev Dodgson said:

roughbarked said:

I can’t even see the video but I’d ask that if the electrostatcic force is too small to deflect the water, could it be assisted by changes in air flow?

I wondered that as well, but I don’t really see why you would get an air flow.

Since I cannot see the video or know of the controls in the experiment, i can only assume that as the cup comes closer to the water the air flow is reduced to the point where the attraction can become greater.

He rubs plastic cup against arm to generate charge, then holds it near the water flowing from the tap. The water appears to be attracted to the cup. Informal experiment, with no real controls.

I might go and have a look at the comments.

p.s.

“mossy”, possibly “stick in the mud” I doubt.

Spiny Norman said:

4. is easy ….
   To get a certain amount of iron into cereal they actually add tiny little flecks of iron into the food.

Yes really!
To check it out, get a full box of cereal, a powerful magnet, give the cereal a good shake with the magnet up against the bag and if you look carefully you’ll see those tiny little flecks of iron stuck to where the magnet is on the side of the bag.

Yes, we got a packet once with excessive amount of iron so much so that it was obvious and they did indeed stick to a magnet

Cymek said:

Spiny Norman said:

4. is easy ….
   To get a certain amount of iron into cereal they actually add tiny little flecks of iron into the food.

Yes really!
To check it out, get a full box of cereal, a powerful magnet, give the cereal a good shake with the magnet up against the bag and if you look carefully you’ll see those tiny little flecks of iron stuck to where the magnet is on the side of the bag.

Yes, we got a packet once with excessive amount of iron so much so that it was obvious and they did indeed stick to a magnet

and it is all a con. what do we want rusty guts for?

roughbarked said:

Cymek said:

Spiny Norman said:

4. is easy ….
   To get a certain amount of iron into cereal they actually add tiny little flecks of iron into the food.

Yes really!
To check it out, get a full box of cereal, a powerful magnet, give the cereal a good shake with the magnet up against the bag and if you look carefully you’ll see those tiny little flecks of iron stuck to where the magnet is on the side of the bag.

Yes, we got a packet once with excessive amount of iron so much so that it was obvious and they did indeed stick to a magnet

and it is all a con. what do we want rusty guts for?

You could probably turn it into a conspiracy involving magnets and alien invasion

Cymek said:

roughbarked said:

Cymek said:

Yes, we got a packet once with excessive amount of iron so much so that it was obvious and they did indeed stick to a magnet

and it is all a con. what do we want rusty guts for?

You could probably turn it into a conspiracy involving magnets and alien invasion

Not looking for that job. I want one that helps pay the bills.

roughbarked said:

Cymek said:

You could probably turn it into a conspiracy involving magnets and alien invasion

Not looking for that job. I want one that helps pay the bills.

Plenty of Sept 11 conspiracists make a living from the public talking circuit, sprouting their woo. Also, why isn’t conspiracists a word?

Divine Angel said:

roughbarked said:

Cymek said:

You could probably turn it into a conspiracy involving magnets and alien invasion

Not looking for that job. I want one that helps pay the bills.

Plenty of Sept 11 conspiracists make a living from the public talking circuit, sprouting their woo. Also, why isn’t conspiracists a word?

Amerkin spelling checker?

Divine Angel said:

roughbarked said:

Cymek said:

You could probably turn it into a conspiracy involving magnets and alien invasion

Not looking for that job. I want one that helps pay the bills.

Plenty of Sept 11 conspiracists make a living from the public talking circuit, sprouting their woo. Also, why isn’t conspiracists a word?

conspiracist

noun

plural noun: conspiracists

a person who supports a conspiracy theory.
“conspiracists sniffed a double murder, possibly by government agents”

gone

roughbarked said:

The Rev Dodgson said:

roughbarked said:

I can’t even see the video but I’d ask that if the electrostatcic force is too small to deflect the water, could it be assisted by changes in air flow?

I wondered that as well, but I don’t really see why you would get an air flow.

Since I cannot see the video or know of the controls in the experiment, i can only assume that as the cup comes closer to the water the air flow is reduced to the point where the attraction can become greater.

You can do the same experiment with a glass and you will see that there is no air effect.

morrie said:

roughbarked said:

The Rev Dodgson said:

I wondered that as well, but I don’t really see why you would get an air flow.

Since I cannot see the video or know of the controls in the experiment, i can only assume that as the cup comes closer to the water the air flow is reduced to the point where the attraction can become greater.

You can do the same experiment with a glass and you will see that there is no air effect.

Thanks for that.

What is special about rotation about one of the three axes that makes it less stable than the other two?

my thought akin to a tightrope walker with a long pole for stability.

I seem to recall they tried No. 1 on QI, using brooms. Everyone managed to do it, except Allan.

JudgeMental said:

What is special about rotation about one of the three axes that makes it less stable than the other two?

my thought akin to a tightrope walker with a long pole for stability.

It is a mixture of physics and ergonomics – I’ll try to explain my thinking. The three axis of rotation as I see them are:

Lengthwise spin – The phone is spinning around the longest axis.

Flat spin – All mass is rotating around a (very) short axis. (Thickness of the phone)

Flip – The phone is spinning around the shortest axis.

When setting the phone into a lengthwise spin, the mass is spinning close to the axis so is pretty stable. While a second axis of rotation around the short axis could exist, it is easy to prevent it when initiating the system by hand. Result? You get what you expect – a phone spinning along the long axis that attempts to resists any nudge to spin in the short axis.

A flip and a flat spin are semi-stable rotations, with all the mass moving around a short axis.

When a phone is ‘flipped’, it only needs a small uneven application of force along the bottom edge of the phone to impart a rotation along the long axis, causing it to rotate as well as flip.

When a phone is ‘Spun’, it also doesn’t need much force to cause it to rotate along the long axis, but because of the way the spin is initiated, there is no such uneven application of force along the shortest axis.

In addition, the difference of the angle of the axis from ideal would also play a large, if not more major role than the above. Flipping the phone along an axis that is not exactly 90 degrees through the centre of the phone would cause a very unstable spin.

which is the same as the long pole.

And the answers are here

Divine Angel said:

And the answers are here

Thanks DA

I think they did a great job on that.

Although I’m still not happy with the phone flipping one (but happier than I was).

Wikipedia doesn’t have a page on the Intermediate Axis Theorem!

thanks DA.

Ta, DA.

I’ll admit that I didn’t realise that water was diamagnetic.

sibeen said:

Ta, DA.

I’ll admit that I didn’t realise that water was diamagnetic.

Glad that one left everyone thinking. I’m now remembering that water has its own attraction.