Width of a Hair Lab

The goal of this lab was to measure the width of a single strand of my hair by using laser diffraction and interference patterns.

Experimental Process

A laser is shined through a thin piece of hair and a split pattern is formed on the wall.

To measure the width of a hair, the equation mλ= ds/D must be used.

- Where m is the number of constructive interferences

- λ is the wavelength of the laser

- d is the width between slits (hair width)

- s is the distance between interference patterns

- D is the distance from the hair to the wall

Using the measurements we collected:

m = 2

λ = 532nm = 0.0000532cm

d = what we are solving for

s = 1cm

D = 190cm

Step 1: multiply both sides by D (mλD= ds)

Step 2: divide by s (d = mλD/s)

Step 3: plug in measurements

d = (2)(0.0000532)(190)/(1) = 0.02012cm

The width of my hair is 0.02 cm thick