Water droplets on CD cover
Billions of atoms of water
It is hard to imagine things that are one millionth the size of a grain of sand. And even harder - having visualized such minute objects - seeing them join billions upon billions of others to fit comfortably into something as small as a teaspoon.
Atoms are such things. They are so small that ~ 1.67 x 10^(20) molecules of water fit in a minute water droplet. If you distributed those molecules to the people on earth, each person would get about 20 billion molecules of water in the palm of their hand.
In the articles that follow, we will see things from an atom’s vantage point. The fact is: electrons are so fast moving that they create a different reality in a nanoscale world.
How many steps can an ant take?
Let's talk about an ant, since the size difference between humans and ants is easier to fathom. An ant is one millionth the size of an average human. While ants and humans seem to have similar speeds (when scaled to size), ants seem to move around much faster.* This is a perception because of their small size within the large space that they scurry around in. It is also due to their continuous movement. It is as if they are always rushing to get ready for work, looking for their misplaced car keys.
But, most importantly, ants do move faster in a unit of time. One way to measure this “rushing” factor is to see how many “ant-steps” the ant takes in a certain amount of time.
Insect pattern design ants
* the fastest ant in the world travels at 1.9 miles/hour (which translates to 108 bodylengths/second - see below)
Putting it into perspective
For very small beings, they move a large number of times for each unit of time. Thus, it is not only the speed of the creature, but it is how many body lengths they can move every second. That is, what is their speed relative to their size.
Here are speeds of various creatures (see also speeds of different animals, if interested):
- Fast humans (say Usain Bolt) move about 6 body lengths/second (bls/second)
- Average ants are somewhat slow, moving at about 10 bls/second.
- A cheetah that sprints at 70 miles/hour moves 16 bls/second
- American cockroaches can cover 1.5 meters (5 feet) in 1 second. The equivalent in their body lengths is 50 bls/second.
- Tiger beetles can run at 4 - 5 mph (6 - 9 km/h) covering 2.5 meters in one second (8 feet). To cross such distances, these beetles - 2cm long - are moving at ~ 150 bls/second.
- The fastest land animal (by body lengths/second) is a mite (Paratarsotomus macropalpis). This mite scurries at an impressive 322 bls/second. That means that each time you blink, the mite has moved about 100 times.
Stretching cheetah in sunset
Small things - in general - move many more times/unit of time when their size is taken into account. This means that though the distance covered per unit time may be similar when elements are matched up for size, small elements are more mobile by several orders of magnitude compared to larger objects.
The reason to place size and time in the same frame of reference is that small things play to a different drummer.
Picture credits:
- James Cridland. A line of ants, Taken on Aug 19, 2007.
- Dima Bushkov Water drops; Few of my experiments with water droplets on a CD cover, Taken on Aug 14, 2009.
- By RATOCA. insect pattern design, ID: 1212670384.
- Sebastien Lorion. ID: 1155930439: Cheetah stretching in the sunset.