chemical change

The disappearing rainbow¹ is a wonderful chemistry demonstration previously featured here on ChemEdX.^2-4 In this experiment, a colorless solution of NaOH is poured into a row of flasks, each containing a different acid–base indicator.

Galinstan is the tradename for a liquid metal alloy that is comprised of three elements: gallium (68.5%), indium (21.5%), and tin (10%).¹ It behaves a lot like mercury but has significantly lower toxicity. Because of this, Galinstan is used as a replacement for mercury in a variety of applications.

The “Pharaoh’s Serpent” chemical reaction involves the thermal decomposition of mercury (II) thiocyanate:^1,2

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.

The floating soap bubble¹ is an experiment that is very easy to set up and carry out (Video 1).

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.

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.

Co-Authored by Tom Kuntzleman* and Grazyna Zreda** *Spring Arbor University, MI and **Tanque Verde HS, AZ

Lightning exhibits some of the most fascinating phenomena on planet Earth.

Once the school year has gotten into full swing, and procedures in lab and with interactive notebooks (INBs) have been established, I begin the chemistry content in my class with learning about matter and how we describe it.