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THE CHATTER BOX

 
  
  
  The Chatter Box : Blathering On
  
  
  
 
Science and Physics. by Ken Dunn on 11 June 2018 9:23am
 
I've started this topic for information because in the past couple of days I've dropped a three of pieces of light paper into the waste bin and all three have missed.
Here is the explanation:
The three pieces of paper were small, light and crumpled. Because of their shape this would cause significant drag or resistance to moving through the air. The waste bin has a column of air above it which can't move downwards because the bottom of the bin is enclosed. Outside the bin the air can move down easily. When the paper is dropped it is effectively sitting on top of a column of air which can't move but gravity pulls it down and with the irregular shape the paper will find the path of least resistance downwards. This path exists outside the central column of air so the paper will move down and sideways to where the air can move easily. If the paper is dropped from high enough it will miss the bin and fall on the floor outside it!
So if you want all your small pieces of crumpled paper to drop in the bin first time do one or all of the following:
1) Squash it tight to make a small ball; then the resistance to moving through the air will be reduced and gravity will overcome the force of sideslip (or high pressure to low pressure movement) before the paper reaches the edge of the bin.
2) Drop the paper from low within the edge of the bin. If it moves sideways it will hit the inside of the bin first.

3) Alternatively, leave the papers on the floor:
a) To cause an argument when someone notices the mess,
b) So that you can explain the physics of why they are there,
c) Until you have time to do the vacuum cleaning,
d) Until someone else does the vacuum cleaning.

See 2) so that none of the parts in 3) are necessary!
 
Re: Science and Physics. by tucsonmike on 16 June 2018 3:02am
 
lol, didn't Galileo already do it?
 
Re: Science and Physics. by Ken Dunn on 17 June 2018 5:13am
 
Yes he did, but in his case there was no waste bin at the bottom of the drop and air pressure would have had negligible effect on the much heavier weights used.

In my case the aerodynamic shape of the piece of paper is also significant as that can cause it to move about as it falls.
 
Re: Science and Physics. by Ken Dunn on 17 June 2018 11:20am
 
OK, some physicists know that Einstein's famous equation is E = M c squared. Where E is energy, M is mass and c is the speed of light. Stephen Hawking created a formula to link quantum theory (describing the very small) with Einstein's relativity (describing gravity and the cosmos).

Hawking's equation is :

T = (h c cubed) / (8 pi G M k)

Where T = temperature (probably absolute), h = Planck's constant, c = the speed of light, pi = 3.14159, G = Newton's gravitational constant, M = mass of black hole and k = Boltzmann's constant.

Most of these identifiers are scientific numbers so what I would like to know is, why is there an 8 on the bottom line of the equation and not a 6? Afterthought - A black hole is basically spherical and the volume of a sphere is 4/3 pi r cubed. If you divide 8 by 4/3 you get 6 so the 8 must relate to the spherical form of the black hole.

Hawking postulated that black holes were not totally black but did radiate and his equation (leaving out the constants) shows that T (the temperature of the radiation) is inversely proportional to M (the mass of the black hole). Therefore, the more massive the black hole, the cooler it's radiation and conversely, the smaller the black hole the hotter it's radiation (we are talking about very low temperature hot e.g 20 degrees absolute is hotter than 10 degrees absolute. Note that 0 degrees absolute = minus 273 degrees C (or is it F)).

Small black holes shouldn't exist for very long as black holes draw in everything it their vicinity (within 1 light year distant?). Larger black holes will draw in everything further afield than this. If the universe has many black holes, as some say, then 'the big crunch' (the opposite of the big bang) will occur many, many years from now.

In a previous post I disproved the Big Bang theory (I'll try to bring it back near here) but it's converse (the Big Crunch) is more difficult to disprove except by saying that if the Big Bang theory can be disproved then its opposite can also be disproved.
 



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