Styrofoam vanishes like magic... or maybe not
You won’t believe your eyes when you see what happens to ordinary packing peanuts when they come in contact with a solvent called acetone. They seem to magically “disappear.” In fact, the Styrofoam reacts with the solvent to reveal the fact that Styrofoam is made up of long strands of styrene molecules with lots of air pockets. This demonstration also reminds us about the importance of reducing our use of Styrofoam and replacing it with more Earth-friendly packing materials.
- Styrofoam packing peanuts
- Styrofoam cups
- Glass jar
- Acetone solvent (this chemical can only be used by adults)
- Styrofoam head used to display wigs
- A 3/4" thick sheet of Styrofoam insulation (found at your local hardware store in the area where insulation is sold)
- 250 mL beaker (8 oz glass)
- Sharpie marker
- Starch peanuts
WARNING: Please follow all of the manufacturer’s safety precautions listed on the container of acetone. This solvent is very flammable. Keep away from all flames.
Use a solvent like acetone to show that polystyrene packaging material is mostly air. The acetone easily dissolves the polystyrene, leaving very little residue. Even though the experiment is called Melting Peanuts, the packaging material is actually dissolving (not melting) in the acetone (melting requires heat). Engage students in a peanut race by seeing which team can fill a bowl first with polystyrene peanuts. Of course, one bowl will secretly contain acetone! Use extreme care when handling acetone — follow the manufacturer’s directions for proper use and disposal.
Air Head – Vanishing Styrofoam Strips
A Styrofoam head used to display wigs is placed on the table along with with long strips of Styrofoam board, approximately 4 cm wide and 70 cm long (but this can vary). The demonstrator uses a Sharpie pen to write down anything important she wants the “head” to know. For this demo, the three R’s of recycling were written down on each of three strips – REDUCE, RECYCLE, and REUSE. You’ll also need a 250 mL beaker or
similar size glass.
- The first step is the trickiest one – to carve a huge hole in the top of the Styrofoam head. Youwant the hole big enough to hold the 250 mL beaker. Forthose non-metric people, you’ll want a glass that holds about 8 ounces of liquid. You can use an electric drill with a door knob hole cutter blade to get the hole started, but it’s going to take a little patience until the hole is just the right size.
- Fill the beaker with 200 mL of acetone (about 6 oz) and carefully lower the beaker into the hole. Be careful not to spill any acetone on the Styrofoam head or it too will dissolve!
- You’ll need a sharp knife (and an adult helper if you’re a kid reading this) to cut the Styrofoam board into long strips. The width of each strip is determined by the diameter of the glass container in the head (250 mL beaker or otherwise). Cut as many strips as you feel the urge to make disappear.Important Note – Some of the Styrofoam board material has a thin, plastic covering on both sides. Remove any plastic wrapping before doing the demo.
- Use a Sharpie pen to write down any words or phrases or whatever youwant to “cram” into the Styro-Head.
- It’s showtime! The story line is up to you… be creative. When it’s time to make the strip vanish, slowly push the strip into the beaker of acetone, being careful not to make the acetone erupt onto the Styrofoam head. The illusion is great as it looks like the strip is “melting” into the head.
Starch-based Packaging Material
As a science teacher or an environmentalist, you are also aware of the bad effects that Styrofoam has on our environment. That’s why many companies have turned to starch packing peanuts as a substitute for Styrofoam. Instead of taking up space in the landfills, starch peanuts dissolve in water to make landfill gravy!
Here’s how it works… Simply wet one end of the colored starch peanut with a dab of water and stick it to another peanut. Build houses, hats, glasses, letters, people, a medieval castle with flying buttresses… just build anything! Use the colored starch peanuts as an icebreaker or team building activity with adults or kids. They’re great for staff meetings!
How Does It Work?
Currently about 200 million cubic feet per year of polystyrene “loose fill” (packaging material) is used in the United States. Although some companies try and reuse the packing material, most of the polystyrene loose fill is disposed of in a landfill. As students of science, we need to carefully examine such products and ask these questions: How is the material made and what happens to it after it is used? One of the properties of polystyrene loose fill is that it does not compress easily. While this is beneficial when trying to protect something from being crushed or broken, it poses a problem when trying to dispose of it in a landfill. As a result, environmentally conscious companies sought a solution to these problems. One such solution is called Eco-Foam loose fill. It provides the ease of use and cushioning of polystyrene, but gives us many other re-use or disposal options for the future. It readily decomposes in water and can be re-used for your own packages, or you can dispose of it by putting it in your compost pile, watering it into your lawn, or washing it down the sink.
Eco-Foam is made almost entirely from an annually renewable resource… corn! The remaining ingredient is a water-soluble organic polymer called “polyvinyl alcohol.” This organic polymer is made from carbon, hydrogen, and oxygen… the building blocks of life. When polyvinyl alcohol is exposed to water, naturally occurring bacteria feed on this organic polymer. Under wet conditions, the bacteria will use the starch (which is also composed of carbon, hydrogen, and oxygen) and polyvinyl alcohol as food to begin the cycle of life again.
Many people feel that the answer to our solid waste problem is recycling. While this method will go a long way to help our solid waste problems, it is not the whole solution. One good suggestion is to use as little of the material as possible. Secondly, it makes sense to use a natural product (instead of a synthetic product) that will break down when we are finished using it. We must remember how to re-use!
Steve Spangler first saw the Styrofoam head demonstration performed by Patti Duncan at the NSTA Convention in Boston. Patti is a high school chemistry teacher who attributes the activity to Doug De La Matter from Canada.