Experiment 10: Measuring human hair

Purpose: to measure the thickness of human hair using a laser and a micrometer in order to compare the two different methods of measureming.

Equipment:

• Notecard
• Human hair
• Tape
• Lazer
• Meter stick

Experiment:

A hole was punched into a notecard, for which a human hair from a classmate was then taped across the diameter of the small perfuration.



In a darkened classroom, the red lazer was turned on, turning the thickness of the hair into a slit to cause a diffraction pattern as observed bellow.

The distance from which the hair was positioned was measured to be ~1meter as displayed bellow

The diffraction pattern was then physically drawn onto the white board suface for further measurements with the classroom light on. This allowed us to visualize the distance between minima as shown in the next image.

Conclusion: 

It was determined that the experimental method of using a lazer to measure human hair was within an acceptable range of value after calculating the uncertainty of its diameter based on the average diameter for black hair.