Photo courtesy of http://www.instructables.com
For many UR students, chemistry has a foreboding reputation. It certainly doesn’t help that a slew of chemistry classes are required for all premedical students, including the dreaded organic chemistry. However, beyond the initial shock of imposing reactions or frustrating equations, there is an underlying beauty to this science.
“Chemistry explains the world around us, from the salt we put on the icy Rochester sidewalks to why we cook the way we do to the fireworks we saw over Meliora Weekend,” chemistry major and senior Emily Hart said. “Chemistry is all around us and the chemist’s eye sees the components and interactions of the materials of the world.”
Chemistry is such an integral part of the world around us, that it should not remain inaccessible. Interesting experiments do not always require a state-of-the-art laboratory with multi-million dollar instrumentation. So forget about Schlenk lines and spectroscopy — many fun reactions can be created in the comfort of your own kitchen.
Oobleck
Named after the green goop in a Dr. Seuss story, oobleck is remarkable for its bizarre fluid properties. While it normally flows like a liquid, when pinched or pushed it temporarily firms up and feels solid.
200 mL corn starch
150 mL water
2 drops food coloring
Combine ingredients and knead well into a gooey paste.
What’s happening?
Rather than fully dissolving in water, corn starch forms a suspension of small particles. Under normal conditions, the suspension can flow freely like a liquid. However, applying pressure compresses and locks these particles together, making the goop act more like a solid. Provided you move quickly enough, you could run on the surface of a large vat of oobleck. But stop moving and you’ll immediately start sinking. Since these strange properties seem to defy Newton’s laws, oobleck is considered a non-Newtonian fluid.
Film Canister Rocket
With a couple of household items you can launch a film canister into the air. You may need to hunt for the film canister, as they are becoming increasingly difficult to find. Be careful: As with any exploding projectile, it can be dangerous.
1 plastic film canister
1 Alka-Seltzer tablet
5 mL water
Add water to the film canister. Break the antacid in half and drop it in. Quickly close the canister and place it on the ground cap-side down. Back away to a safe distance.
What’s happening?
The active ingredient in antacids is sodium bicarbonate (NaHCO3). When dissolved in water, the bicarbonate ion (HCO3-) quickly breaks down into water and carbon dioxide. As carbon dioxide is rapidly produced from the solution, gas builds up within the canister. This increasing pressure is released in a sudden explosion that pops off the cap and launches the film canister into the air.
Elephant Toothpaste
100 mL 6 percent hydrogen peroxide (this is commercially available as 20-volume peroxide bleaching solution. If you have access to 30 percent hydrogen peroxide, much more foam is produced.)
1/2 packet yeast
5 mL dishwashing detergent
1-2 drops food coloring
Combine the peroxide and detergent in a 16 ounce bottle or cup and add food coloring if desired. Next pour the dry yeast into the mixture.
This reaction is adapted from one described at sciencecafe.org.
What’s happening?
The oxygen-oxygen bond in hydrogen peroxide (H2O2) is very reactive, making the molecule a powerful oxidizing agent. The yeast readily catalyzes the decomposition of hydrogen peroxide into water and oxygen gas. As oxygen bubbles through the soapy solution, thick foam rapidly develops. In the process, the reaction releases a lot of energy as heat, so the flask will heat up. Be prepared because the solution will expand very quickly and gush out of the glass, but don’t worry too much about making a mess. The result is just soapy water. Plus, if you drop a lit match into the solution, it will burn because the foam is filled with oxygen gas.
Still not satisfied? If you’re interested in more exciting reactions, then come to the Undergraduate Chemistry Council’s “Chemistry in Action” magic show on Thursday, Dec. 15 at 9 a.m. in Hubbel Auditorium.
Raybin is a member of the class of 2012.
