Science Buddies: "Ask an Expert"

Hi I just got an account on this website and I really need help. I have a science fair project due by 12/13/12. I chose to do my project on the permeability of different plastic wraps using water evaporation. I think you would also like to know that I am in 6th grade. I have an introduction packet that is 9 pages long . Can you help? Thanks

Hello scienceck,
Do you have specific questions about your project that you need help with? Have you read the introduction packet? If you have not, that might be a good start. After you read it, make a list of the materials you need to collect to carry out the experiments so that you can get them. Also, you need to make a list of the tasks you need to complete like:
-What is the hypothesis for your project?
-What are the variables?
-How will you set up the experiments?
-What is the data you will collect?
-How will you analyze this data?
By going through this process you may come up with specific questions we can help you with. In general, the more specific your questions, the better.
Hope this helps!
Veronica

Sorry I didn't give you much info. And yes I did read the packet. Thank you for the list. That was very helpful. I just need to know what is in Glad plastic wrap. Thanks alot .

A good source of information about what is in any product on the market in the United States is the "Material Safety Data Sheet".
If you put "Glad Plastic wrap MSDS" into a search engine, you will quickly find:
http://www.thecloroxcompany.com/downloa ... adwrap.pdf
which will tell you that the material is Polyethelene.

I didn't find a Saran Warp MSDS; however, the SC Johnson Company prides itself in disclosing what is in all of their products, it just takes a little more searching. On their Saran web pages, there is a FAQ What ingredients are in Saran ™ Plastic Wraps?" that states it is polyethelene.

From a food safety standpoint, polyethelene is likely to be the ONLY material used by all the plastic wrap manufacturers.

If you search for "permeability of polyethelene", you might find an old Bell Laboratories article from 1966 http://www.alcatel-lucent.com/bstj/vol4 ... -2-391.pdf that offers some hope of finding differences in permeability of water vapor in various polyethelenes; however, the competitive nature of the pastic food wrap business might have driven the major competitors to provide similarly performing products.

There are some high end commercial restaurant supply vendors that sell thicker polyethelene food wraps at a higher price point that may have a lower permeability.

In any case, the permeabilities of polyethelene are low enough that any seal leakage around the edges is likely dominate any test results and your test proceedures are going to have to figure out how to eliminate that leakage if you really want to test permeability of the material.

This line of thought leads to an alternative experiment that ignores the permeability and tests for how well various manufacturer's "cling wrap" seals to identical containers. If you head that direction, you will have to control the cleanliness of the surface of the identical containers. Any skin oil or other surface contaminant could alter the effectiveness of any plastic wrap product.

This is scienceck Doing a science project using different cling wraps. Reynolds cling wrap made with (PVC) is discontinued. Any cling wraps you know of made with PVC? Thanks

Hi:

I tried using a search engine with the terms "PVC film" and found lots of links to manufacturers. You could also look at the Thomas registry: http://www.thomasnet.com/products/pvc-f ... 332-1.html. I don't know if you can find any of these films locally, but hopefully you can buy relatively small quantities somewhere on the web.

Keith

Try putting "pvc food wrap film" into a search engine to find some sources.

Hi! I have a bibliography worksheet to do. I already put down science buddies but do you know of any other website that has any info on plastic wrap and evaporation? Thanks