Your thumbnail is about 10 millimeters wide.
A mustard seed
Normally a pen is somewhere around 8mm wide but you never know, there may be 8cm wide pens! Normally 8mm
A single strand of hair can be from 18 micrometers to 80 micrometers in width.
millimeter
Yes, a millimeter can be as wide as a strand of hair. The average human hair is about 75 micrometers in diameter, which is equivalent to 0.075 millimeters.
a millimeter
not even a millimeter
Your thumbnail is about 10 millimeters wide.
A mustard seed
Create a 6-inch ball of millimeter wide tinsel. Take a tube, and rub it in your hair for 10 seconds. Then put the ball on the rubbed part, it will float away.
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Hair grows at the same rate for both men and women. The average rate that hair grows daily is half a millimeter.
Whatever it is, if it measures 1,000th of a millimeter wide, it is 1 micron wide. Examples of some small measurements: A typical human hair is 100 microns wide (a 1/10th of a millimeter). A red blood cell is 7 microns wide (less than 1/100th of a millimeter). Here's a neat interactive video of small things for you: http://www.cellsalive.com/howbig.htm A staphylococcus bacteria in the video looks to be just under 1 micron wide. Most viruses are much, much smaller still!
A micrometer is a millionth of a meter, and therefore a thousandth of a millimeter. Therefore, you simply divide the micrometers by 1000, to convert to millimeters.
Eighteen thousandths of a millimeter. 0.0018 cm = 0.018 mm = 18 µm (micrometer) Human hair width actually ranges from 17 to 181 µm. 181 µm is almost .2 mm so you could say "about a fifth of a millimeter for coarse hair"
It's about 500 feet long and 200 feet wide