Solution to Chemical Mystery #15: The Leaky Cup
The solution to Chemical Mystery #15: The Leaky Cup is shown here.
The solution to Chemical Mystery #15: The Leaky Cup is shown here.
Time for a new chemical mystery! Watch the video below and see if you can use your chemical knowledge to figure out how this experiment is done.
What happens if you cool a Scrub Daddy sponge in liquid nitrogen (or dry ice) and subsequently strike it with a hammer? Let's find out!
The science behind the incredibly popular Scrub Daddy sponge is investigated. Part of the appeal of the Scrub Daddy sponge is that it changes from soft to hard depending upon temperature. This allows a single sponge to be transformed into a hard scrubber or soft sponge, depending upon the temperature of water into which it is placed.
The authors of the recent Journal of Chemical Education article, PolymerDay: Outreach Experiments for High School Students, offer a collection of interactive polymer activities designed to be part of an all-day outreach event for high school students. For teachers that might use the activities on separate occasions and/or as part of their curriculum, the authors recommend an accessible resource to support that work.
This is an ACS Authors' Choice article and is open access to all.
In this Activity, students compare polystrene and cornstarch packing materials ("peanuts"). Both are made of polymers, but because of their composition, they behave very differently in various solvents. Students extrapolate how these differences in behavior relate to environmental effects, such as filling landfills with non-biodegradable materials.
In this Activity, students first prepare a gel using the superabsorbent polymer sodium polyacrylate (found in certain diapers) and water. The gel is split into piles and samples of different compounds are sprinkled on the piles. Students determine that ionic compounds break down the gel, while covalent compounds have no effect on the gel.
In this Activity, students dye fabric squares with two plant dyes: aqueous extracts of tea leaves and of marigold flowers. They investigate how the addition of iron to a dye bath affects the resulting color and fastness of the dyed fabrics and observe that the type of fabric affects the results. This Activity can accompany a discussion of the impressive array of chemicals produced by plants.
In this Activity, students develop fingerprints using the cyanoacrylate fuming method on different types of surfaces. They investigate the technique’s effectiveness and test the effects of changing the temperature and humidity of the fuming chamber.
In this Activity, students investigate the physical properties of different balls that may look similar, but have very different rebound properties. Students also investigate how the rebound properties change when the balls are subjected to near freezing and near boiling temperatures. This Activity could be used at the beginning of the school year as an exercise in making observations.