The "gel worm" lab on synthetic polymers is a class favorite! Students are surprised and entertained when they put their fingers into the two liquids they combined to pull out the stretchy polymer that has formed.
This lab is appropriate for middle school students, and I have used it with students in grades seven and eight.
The American Chemical Society has created free, engaging labs that align with the Next Generation Science Standards. This polymer lab addresses the standard MS-PS1-3: Gather and make sense of information to describe that synthetic materials come from natural resources and impact society. The lab comes with a comprehensive lesson plan that compares natural products with synthetic ones, and it is a great starting point for a larger discussion on the role of synthetic plastics in our world.
The reactants used to produce the "gel worm" polymer are sodium alginate and calcium chloride. Sodium alginate can be found online, and the most cost efficient way to purchase calcium chloride is buying unscented DampRid, which consists of pure calcium chloride and is available in hardware stores. I find it easiest to make the solutions at least a day in advance. The first time I tried making the sodium alginate solution, I spent a long time slowly adding the solute and shaking the solution, but I couldn't get all of the sodium alginate to dissolve. I later discovered that simply letting the solution set overnight resulted in a nice solution without clumps.
If you would like to try this fun lab with your students or your own children, follow this link:
American Chemical Society Lab: Natural Resources & Synthetic Materials
That activity looks like so much fun!
ReplyDeleteStudents do find it fun!
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