B Help with Physics lab idea (creative)

[E11ie]

Hiya!
In school we have tha task to create our own phy lab. I am going to investigate the width of a hair using wave diffraction (a laser maybe?).
Does anyone have any creative ideas on how to develop the lab to make it more uniqe and interesting. E.g measuring from different distances. Or maybe even another procedure than a laser?
Thankful for any tip
-Ellie

 

[jedishrfu]

You could demonstrate the accuracy of the scheme by:
- using different lengths of hair to screen
- using different minimums
- using different colored lasers
- using a micrometer
- measuring the width of a 100 hairs
- measuring different hairs from family, friends, strangers and pets.

You could also measure violin bow hair, or paint brush hair or a bristle from a room

and for the violin hair you could add rosen to see how mush its width changes
or soak the hair in water to see if it changes.

You could contrast the hair width with other thin things like a sharp pencl line, or the edge of paper.

 

[Dadface]

perhaps you could try measuring by how much the width of hair (and its length) changes with humidity. To understand why I'm suggesting this google "hair hygrometer".

 

[mishima]

Try something crazy small, too.

I had a high school student once do something similar to measure the width of an onion cell. Afterwards (or maybe prior to...cant really remember) he stained the cell and got an actual measurement using our digital microscope. We found the idea in an issue of the Physics Teacher, not sure which one exactly. To make it work he had to use an UV laser projected on neon poster board, because the normal lasers were too dim at the distance we used (something like 10 feet).

 

[E11ie]

demonstrate the accuracy of the scheme

You could demonstrate the accuracy of the scheme by:
- using different lengths of hair to screen
- using different minimums
- using different colored lasers
- using a micrometer
- measuring the width of a 100 hairs
- measuring different hairs from family, friends, strangers and pets.

You could also measure violin bow hair, or paint brush hair or a bristle from a room

and for the violin hair you could add rosen to see how mush its width changes
or soak the hair in water to see if it changes.

You could contrast the hair width with other thin things like a sharp pencl line, or the edge of paper.

What do you mean by "using different minimums"?, thank you for the answer! very helpful:)

 

[jedishrfu]

They usually use the first minimum width when making the calculation. However the formula allows for 2nd, 3rd ... minimums to be used. The minimums are the dark bands as counted from the center of the beam on the wall with the first minimum being the closest dark band to the right and left of the center.

Here's a diagram showing minimums and a diffraction image:

 

[ZapperZ]

Hiya!
In school we have tha task to create our own phy lab. I am going to investigate the width of a hair using wave diffraction (a laser maybe?).
Does anyone have any creative ideas on how to develop the lab to make it more uniqe and interesting. E.g measuring from different distances. Or maybe even another procedure than a laser?
Thankful for any tip
-Ellie

First of all, let's establish that you know how to do the "standard" experiment with this. It should be similar to what has been described here:

http://www.jedc.org/stemak/sites/default/files/Measuring the diameter of a hair using a laser.pdf

In terms of how to make it more "unique and interesting", it depends on what you have available to you. Do you have a number of laser pointers with different wavelengths? Maybe repeating this experiment with different wavelengths and figuring out which ones might give you a more accurate measurement might be a simple and slightly different approach.

Zz.