Measuring a human hair

The purpose of this project is to measure accurately the thickness of a human hair by using diffraction.

We will obtain a human hair and tape it across the hole of a 3x5 note card. The card will be clamped parallel to the board several meter from the board. We will then shine a laser to the hair which will produce a diffraction pattern on the board. The first - order (m = 1) minima  will show on the board and then we can use the diffraction formula to calculate the width.