# The Nature of Chemistry

Apple Candle – Light a “candle”, let it burn a minute, blow it out, then eat it, wick and all. (The “candle” is an apple with an almond wick, but it looks exactly like a real candle.)

Burning Iron and Magnesium – Contrast the results of holding an iron strip and a Mg ribbon in a flame

Burning Magnesium Ribbon – Burn a piece of magnesium ribbon in air to produce MgO

Chemisty and Your Senses – Present five short and simple demos which relate chemistry to the 5 senses. Includes Rainbow Cups, Vanilla Balloons, and Sound.

Density of Coke vs. Diet Coke – Drop unopened cans of regular Coke and Diet Coke into an aquarium filled with water. Coke sinks and Diet Coke floats – challenge the class to postulate an explanation.

Density Demo – Candle – Display a 1 L graduated cylinder with a colored candle stub floating at the half-way point in a clear colorless liquid, and ask the students to explain this phenomenon; then drop candle stubs into separate beakers of ethanol and water to show that the candle sinks in ethanol but floats in water – the cylinder contains water and ethanol in two layers, so the candle stays at the interface.

Density Demo – Silver – Determine the mass of a “silver” cube on a balance which displays the mass on the overhead projector, then determine the volume of the cube by water displacement in a 250 mL graduated cylinder, and finally calculate the density to answer the question “Is this really a silver cube?” A transparency showing the density of five “silvery” metals is provided to help the class identify the cube as aluminum, not silver.

Dry Ice Sublimation – Make the sublimation of dry ice “visible” by dropping a piece of dry ice in a beaker of water. (Optional: place a piece of dry ice in a glove, tie it off, and allow the dry ice to sublime, inflating the glove.)

Electrolysis of Water – Electrolyze water (dilute Na2SO4 solution with indicator) in the Hoffman apparatus to decompose it into its component elements, hydrogen and oxygen. If desired, you can test the H2 (g) and/or O2 (g) produced with a flame and a glowing splint, respectively.

Elements and Compounds – Show bottled samples of various elements and some compounds containing those elements (e.g. Mg, Cu, and S with MgSO4 and CuSO4 or Na and Cl2 with NaCl)

Ethanol – Composition, Structure, and Reaction – Use a flask of 95% ethanol, a ball-and-stick model of ethanol, and burning ethanol in a watchglass to introduce the terms composition, structure, and reaction, which briefly summarize what the science of chemistry is all about.

H2-O2 balloons – Ignite a balloon filled with a stoichiometric mixture of hydrogen and oxygen to show the extremely exothermic reaction to produce water.

Halogens – Display flasks containing the halogens chlorine, bromine, and iodine.

Happy and Unhappy Balls – Start with a pair of seemingly identical rubber balls to discuss potential and kinetic energy. One ball bounces like a superball, and the other absorbs energy and does not bounce.

Penny vs Nitric Acid – Read Ira Remson’s own account of his first encounter with chemistry as you repeat his experiment by pouring concentrated nitric acid over a copper penny.

Precision and Accuracy – Measure a brass rod using overhead transparency rulers divided every 5 units, every 1 unit, and every 0.1 unit to introduce the concepts of precision and accuracy or significant figures

Rainbow Cups – Add a colorless liquid to 6 “empty” beakers, producing the colors of the rainbow – use this demonstration to show how evaluation of observations and experimental results leads to hypotheses and further testing (the scientific method).

Ripping Pop Cans in Half – Ask a student to rip an aluminum pop can in half. When they cannot, demonstrate “proper” technique by effortlessly ripping a specially prepared can. Then hand them a prepared can and ask them to repeat the activity.

Separation of a Mixture: Iron and Sulfur – Separate iron filings and sulfur with a magnet

Smashing Things with Liquid Nitrogen – Demonstrate the coolant properties of liquid nitrogen by freezing a racquet ball or another object of your choice and smashing it.

Zinc and Sulfur – Lay a red-hot iron rod into a powdered mixture of the elements iron and sulfur to produce a non-magnetic compound, iron(II) sulfide, FeS (s)