About a decade ago, I wrote briefly about the interesting experiment of throwing boiling hot water into air that is below -18°C (0°F) (see Ice Clouds). WARNING: If trying this experiment on your own, be certain to NEVER throw boiling water into the wind. Make sure the water is thrown with the wind, away from you. Doing so not only keeps you safe but also creates a much more magnificent effect. Also, having the cloud backlit by the sun helps to accentuate the beauty of the experiment as well. During a particularly cold snap here in Michigan, I repeated these experiments with some family membe ..read more

Many have asserted that the water we drink is exactly the same water that has been eliminated from the bodies of humans and animals from the past. The argument goes that water excreted from our bodies by exhalation or urine ultimately ends up back in the water cycle. That is, water eliminated from biological organisms finds its way into rivers, lakes, ponds, and oceans. This same water evaporates back into the atmosphere, and rains back down onto the Earth in an endless cycle. Because the water we consume comes from water that participates in this timeless process, it stands to reason that w ..read more

A classic chemistry experiment1 involves using a concentrated solution of KNO3 to “paint” a design in a continuous line on a piece of paper, allowing it to dry, and then igniting one end of the paper (Video 1).2 Video 1: Chemistry is Love, Tommy Technetium YouTube Channel, Sept 26, 2022.   One way to explain this result is that the ignition of the paper causes the KNO3 to thermally decompose, producing oxygen gas:1 2 KNO3 (s) → 2 KNO2 (s) + O2 (g)                       ..read more

The floating soap bubble1 is an experiment that is very easy to set up and carry out (Video 1). Video 1: Floating Bubbles? Tommy Technetium YouTube channel, accessed 8/19/23.   Isn’t that a beautiful effect? My students certainly find this effect to be rather captivating. This experiment is also quite popular with younger students, so it tends to be a real hit at outreach events. I present the floating soap bubble experiment to my students in class at the beginning of the year when discussing the topic of density. However, because this experiment can be used in a wide variety ..read more

Jet-Puffed color changing marshmallows are an interesting new product that is available on the shelves of grocery stores through the end of September.1 The color of these marshmallows changes when exposed to heat: the blue version turns green, while the pink version turns orange. Representatives at Jet-Puffed report that a “secret color changing ingredient” is used that is responsible for the color changing effect.1 Naturally, we all want to know that this secret ingredient is! So I went to work in the lab to see if I could figure anything out. You can see the results of my investigatio ..read more

An experiment that has always fascinated me is observing what happens when CO2 is bubbled into limewater (which is a saturated solution of calcium hydroxide).1-2 This experiment can be carried out by blowing bubbles of exhaled breath (which contains roughly 4% CO2)3 through a straw into limewater. A series of reactions convert the calcium ions in the limewater into calcium carbonate:1-2, 4-8 CO2(g) ⬌ CO2(aq)             Eq. 1 CO2(aq) + H2O(l)  ⬌ H+(aq) + HCO3-(aq)           Eq. 2 Ca2+(aq) + 2 HCO3 ..read more

The chemistry demonstration called the self-carving pumpkin1 is a blast (no pun intended) to conduct around Halloween. To prepare this experiment, a jack-o-lantern face is carved into a pumpkin, but the eye, nose, and mouth pieces are saved. These pieces are then gently placed back into the holes in the pumpkin. Next, a small hole (through which a nozzle-nose lighter can be inserted) is cut in the back of the pumpkin. When ready to carry out the experiment, calcium carbide is added to a container of water positioned in the jack-o-lantern, and the “lid” is placed on top. Acetylene gas builds ..read more

On February 3, 2023, a train derailed in the town of East Palestine, Ohio.1-2 Five of the train cars were carrying vinyl chloride (Figure 1), a compound that is mostly used to make PVC. Figure 1: Chemical structure of vinyl chloride, C2H3Cl The vinyl chloride was combusted because of the accident, and also from controlled burning of vinyl chloride initiated by authorities.1,2 Vinyl chloride is a carcinogen, and its combustion of vinyl chloride is known to release HCl, phosgene (COCl2), and CO through a variety of pathways.3 For example, HCl can be formed through the reaction: 2 C2H3Cl(g) + 5 ..read more

Various items (hot dogs, bananas, flowers, racquetballs, plastic cups) show properties akin to glass when chilled in liquid nitrogen.1-4 Objects such as racquetballs and plastics behave in this manner because they are made of polymers, and polymers can become cooled below what is known as the glass transition temperature (Tg) for the polymer.3-4 Above Tg plastics are elastic, near Tg plastics lose their elasticity, and below Tg plastics become brittle (Video 1).   Video 1: SCRUB DADDY vs. LIQUID NITROGEN, Tommy Technetium YouTube Channel, October 2022.   Did you know tha ..read more

Co-Authored by Tom Kuntzleman* and Grazyna Zreda** *Spring Arbor University, MI and **Tanque Verde HS, AZ With Halloween right around the corner, we thought we’d share with you a demonstration we’ve developed that’s great for this holiday. The reaction is a modification of an orange-to-blue reversible reaction that makes use of copper, hydrogen peroxide, and tartrate ion (Video 1).1-3 To a 250 mL beaker, add 125 mL of water, 2 tsp cream of tartar and 1 tsp Na2CO3. Then add 2 Tbsp (30 mL) 3% H2O2. (If the mixture is not mostly clear, then add slightly more Na2CO3.) T ..read more