The head of a pin is about 2mm in diameter. Use this animation to compare the relative sizes of cells and organisms sitting on a pinhead. Nearly invisible without magnification, dust mites dwarf pollen grains and human cells. In turn, bacteria and viruses are even smaller.
How to Use
Use the left and right arrows to change magnification.
Click on the magnifications (1, 10, 100...) for a "Power of Ten" zoom.
Choose an individual cell or organism (right) to bring it into view.
Use the scale to measure individual cells.
1 millimeter = 0.001 meter
1 micron = 0.000001 meter
1 nanometer = 0.000000001 meter