Glossary

 

kilo means x1000. In units of length it espressed as: km and in units of weight it is expressed as: kg

1km = 1000m or 1x10³m, and 1 kg = 1000g or 1x10³g

centi means 1/100^th. In units of length it is expressed as: cm (centimeter)

1cm = 1/100^th of a meter, also written as: 1x10 ^-2 m

or: 100 cm = 1m

milli means 1/1000^th. In units of length is is expressed as: mm (millimeter). In units of weight it is expressed as: mg (milligram)

1mm = 1/1000^th of a meter, also written as: 1x10^-3m. Also: 1000mm = 1m

1mm = 1/10^th of a centimeter, also written as: 1x10^-1cm. Also: 10mm = 1cm

1mg = 1/1000^th of a g, also written as: 1x10^-3g

micro means 1/1000 000^th. In units of length it is expressed as: µm (micrometer)

1µm = 1/1000 000^th of a meter, also written as 1x10^-6m.

Bacteria are in the size range of 1µm. A typical human cell (as well as animal and plant cells) has a diameter of 10-20µm. A human hair has a diameter of about 100µm.

The size of objects inside a cell is measured in nano meters (nm).

nano means 1/1000 000 000^th. In units of length is is expressed as: nm (nanometer)

1nm = 1/1000 000 000^th of a meter, also written as 1x10^-9m.

Many molecules are in the size range of 1nm, while viruses are about 100nm accross.