How Big Are Things? Home     Welcome	small		Real world	big			solar system		between	galaxy
	nano	micro		meter	kilo		Mega	Giga	Tera	Peta	Exa

um = 10-6 m

look at a sheet of graph paper

galaxy		21
		20 19
local stars		18
		17 16
between		15
		14 13
E's orbit		12
		11 10
sun		9
		8 7
texas		6
		5 4
hood		3
		2 1
you		0
		-1 -2
salt grain		-3
		-4 -5
bacteria		-6
		-7 -8
atom		-9

bacteria ~1 um red blood cell ~10 um hair ~100 um dia

original

grain of salt ~1000 um

		card paper   thick paper   plain paper   thin paper
		a sheet of paper

one day's hair growth

light-picoseconds ( 10-12 lt·s )
0	1	2	3	4	5

inches  mils (1/1000 inch)
0	10	20	30	40	50	60

typesetting's points (pt) (1/72 inch)
0	1	2	3	4

1200 dpi
600 dpi
300 dpi
100 dpi
/tr>

your screen (If you sputter tiny drops of water on your screen (spit works), you can see them.)

The letter "a", and a period, in a 12-point font.
You can make your own big letter "a" poster.

a 20 uL drop (on a hydrophobic surface, like tile, or glass, or ...)

source The eye of a needle.

pin diameters	pin source, img

These are adult fleas. They feed on blood (see the fangs). Of big animals (mice, rats, cats, dogs, humans, etc). They have narrow bodies for running through hair forests. They can jump high - 100 mm (in this room, that's a thirty story building), surviving 200 G's on takeoff (ie, they leap tall buildings in a single bound:). Vampire bear? Elephant?

source

q-tip src

alveoli balloon-like

smallest raindrops src

typical raindrop src

quarter

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