FYSIKbasen.dk - The Danish database for physics demonstration experiments.
Home News Database About Contact Danish

Measure the thickness of your hair!

FYSIKBASEN.DK would like to invite all visitors to perform this demonstration experiment where you measure the diameter of your own hair. The result is calculated and submitted using the form below. At Fysikbasen we will calculate some statistics on all the measurements, we hope to receive.

The only thing you need is a laser pointer and a tape measure. On this page it is assumed that you are using a standard red laser pointer. You should probably be two persons when performing the experiment.

How to do it:
  1. Place the hair in front of the laser so that an interference pattern is formed:


    It is a good idea to attach the hair to the laser using adhesive tape.

  2. Point the laser towards a screen, a wall, or similar. Measure the distance L (in centimeters) from the hair to the interference pattern on the screen (use for example 200 cm or more):

    L = cm

  3. Now measure the distance x (in millimeters) from the bright center to either the first (order = 1), the second (order = 2), or the third (order = 3) dark band.

    x = mm   ,   order =

  4. Choose the color which describes your hair color the best:

  5. Enter your name and email address. Your email will >not be made public:

    Name:    ,   email:

  6. Finally, enter the password "laser" in the following field. This is to avoid spam:


  7. Click the send button to submit your measurement. You will also get the result of your measurement:


Any questions regarding this demonstration can be mailed to :