Sunscreen and UV rays

kdozier · Post by **kdozier** » Mon Nov 13, 2006 2:28 pm

My question is about uv beads. I want to do a project on sunscreen and wanted to know if I put different sunscreens on the uv beads if that woudl work? The book calls for photosensitive paper.

hhemken · Post by **hhemken** » Mon Nov 13, 2006 3:13 pm

I see on the page of a manufacturer of the beads that they can be used to evaluate sunscreens (I know nothing about this vendor, this mention of it does not constitute a recommendation or approval of any kind):

http://www.stevespanglerscience.com/product/1350

I didn't even know these existed! They look interesting. They are inexpensive enough that you would be best off just buying some and testing them (let us know how it goes!). I would suggest buying sunscreen of the same brand in a wide range of protection levels, and testing all of them in the same experiment.

I don't know how fast the beads change, but I suspect you might be able to measure total color change time as well as whether the beads achieved a full color change as indicated by untreated beads within a set amount of time.

Good luck!

deleted-71576 · Post by **deleted-71576** » Mon Nov 13, 2006 8:20 pm

We looked at those beads for my son's science fair project last year. Please check on how sensitive they are to UV rays before purchasing them. If memory serves, they were too sensitive, and we decided that they would be difficult to use with lower SPF value sunscreens, as they would uniformly change color, and not be able to differentiate less effective sunscreens.