Science Buddies: "Ask an Expert"

I need help finding pollen less than 0.001 millimeters in size for my science project. My project is based on Robert Brown's Brownian motion (random walk) which states that Brownian motion only acts on particles less than 0.001 millimeters in size since the particles have to be small enough to be affected by nuclear forces. I would prefer pollen that is from a plant that can be commonly found. Thank You

Revised: I Changed the Subject from Pollen to Particle

Please Reply

Hi Wesley2894,

Welcome to the Ask an Expert forums. Your project topic is an interesting one for me, because certain mathematics of diffusion are a regular part of my own work.

Do you have to use pollen? From what I gather, 1 micron (0.001 mm) is at the lower end of the size range for most pollen, as well as fungal spores. If you run an internet search for "particle size microns" you will find some tables of particle sizes of various materials.

By the way, this forum is designed for long term assistance as opposed to immediate responses. Our experts are usually assigned one day per week, so it might take a few days before you receive a reply to any given question. If you depend on our assistance, please allow plenty of time.

Looking forward to hearing more.
Chris

I recall in school using a dye as a model for Brownian motion. It's also easier to see!

I agree with ChrisG, if you expand beyond pollen, you should have an easier time finding particles of the right size for your experiment.

Here is a link that I found searching on google. http://www.kcprofessional.com/us/downlo ... eRange.pdf It says that milled flour is 1-90 microns. What flour is on the 1 micron range?

here's a book page that talks about flour size: http://books.google.com/books?id=uA3zkm ... lt#PPA3,M1

Cake flour might have a finer texture overall. But I don't think you will find a bag of flour where all the particles are that small. More likely, the finest flours will contain a range of particle sizes, some of which are that small.

Can you tell us more details about your hypothesis and proposed experimental design? That would make it easier for us to help you find a solution.
Nano-and micro-spheres are available for purchase, but the prices are high for a science fair project. If you need a couple of sizes above and below 1 micron, the lowest cost solution might be > $100+.
http://www.microspheres-nanospheres.com ... /Glass.htm
Would those suit your needs? If you call the company and explain the situation with your science fair project and your budget (ask if they have any sort of "educational discount") it's possible they will give you a discount or sell a smaller but sufficient quantity. You might be able to offer them some exposure by giving credit on your science fair board. It's a long shot, but who knows.
I hope that helps.
Chris

Hi!
I agree, it might end up to be very costly. Perhaps you could go with synthetic particles like zircon flour which is in this link-
http://www.meshwoceramics.com/profile.html
just to give you some more ideas of relative sizes of particles-
http://athma.pnn.com/articles/show/1313 ... -particles
alternatively, you can also check out these websites-
http://www.wholywater.com/filter.html
Good luck!