BIG LITTLE SCIENCE CHEMISTRY SHOW:
Planning amounts for 3 shows, plus 3 trial runs
1. LUMINOL “LIGHT PIPE”
big stand with clamps and tubing
2 L beaker
big glass funnel
Solutions: 3–Bottle A (Dilute 4.0 g Na2CO3 to 500 mL, add 0.2 g Luminol and stir to dissolve. Add 24.0 g
NaHCO3 , 0.5 g (NH4)2CO3•H2O and 0.4 g CuSO4•5H2O and dissolve. Dilute to 1 L.)
3–Bottle B (50 mL of 3% H2O2 diluted to 1 L)
To Perform: Pour equal amounts of bottles A and B into funnel, with lights off (adjust pouring rate to get maximum glow)
What is Happening: Luminol is a special molecule which reacts to form a product having electrons in a highly excited energy level. As the molecule loses energy and its electrons fall down to a lower energy state, the energy lost is in the form of light.
2. DRAGON’S BREATH
Candle taped to the end of a meter stick
Chemicals: Make a mixture of 100 mL of ethanol, 15 mL of water and about 3 g of lithium chloride. Shake to
dissolve as much lithium chloride as possible.
Put about 50 mL of ethanol in the spray bottle. Hold a lit candle at arm’s length. Hold the spray bottle about 4–6 inches from the candle and quickly spray ethanol through the flame.
This should produce a nice little fireball that lasts for a second.
3. ELEPHANT’S TOOTHPASTE
500 mL graduated cylinder
sponges for clean up
Solutions: 300 mL of 30% hydrogen peroxide
45 mL of dish washing detergent
30 g of potassium iodide
WEAR GLOVES! Pour about 100 mL of hydrogen peroxide into the graduated cylinder, add about 15 mL of detergent and add about 10 g of sodium iodide. Huge yellow worm springs out of cylinder!
What is happening: The hydrogen peroxide oxidizes the iodide ion to iodine, while simultaneously releasing oxygen gas. The gas is trapped in the detergent, creating a foam.
4. SHAVING CREAM IN A VACUUM
bell jar with bell jar base
can of shaving cream
large Petri dish supported over three pieces of wood (to avoid plugging of air exit hole)
Put a generous daub of shaving cream in Petri dish, put bell jar over dish base, turn stopcock to off, connect vacuum pump to bell at stopcock and turn on pump. Open stopcock and watch shaving cream swell up and completely fill inside.
What is happening: The shaving cream is full of gas bubbles in equilibrium with the gas pressure of the atmosphere pushing down on the bubbles. When the air is removed, the bubbles expand.
5. DISAPPEARING WATER
Equipment: Part A:
small glass (with even lip)
6–pieces of cardboard (About 15 cm x 15 cm)
Part B: Styrofoam cup
15 cm square piece of cardboard having “Do not remove this cardboard” written on
400 mL beaker
Chemicals: jug of water, sodium polyacrylate powder
To Perform: Part A: Fill the glass 3/4 full of water, place the cardboard over the end of the glass and invert the glass. Let go of the cardboard and the water stays in the glass.
Part B: Put some sodium polyacrylate powder into a Styrofoam cup (ahead of time, unseen).
Have a student hold the cup in the air with both hands. Then pour water out of the pitcher into the cup and put the second piece of cardboard over the mouth of the cup. While the student is still holding the cup, turn it upside down over the student’s head and lower the cup onto the student’s head. Then, pull the piece of cardboard out and have the student read the card. Finally, lift the cup up off the student’s head, showing that no water comes out.
What is Happening:
As the water tries to come down out of the glass, the pressure inside the cup is lowered. The greater pressure of the atmosphere outside then pushes the cardboard firmly against the rim of the glass.
The sodium polyacrylamide quickly forms a gel when water is added.
6. MELTING STYROFOAM CUP
250 mL acetone in juice bottle, with small label
500 mL distilled water in juice bottle, with small label
4 new Styrofoam cups
Pour distilled water into cup and drink. Ask if someone else wants a “nice strong drink” and quickly pour half a cupful of acetone (HOLD IT OVER AN ORANGE BUCKET WHEN OFFERING IT TO SOMEONE – you have 3 seconds before the bottom drops out!)
7. DRY HANDS IN WET WATER
2 L beaker
jug of water
Chemicals: Lycopodium powder in a test tube
Pour test tube of Lycopodium powder onto the surface of the beaker of water. Slowly push hand below the surface of the water and then bring your hand back out. The hand will be dry.
What is Happening: Lycopodium powder is “hydrophobic” (it repels water, similar to oil). When a hand
is pushed down into the water, a thin layer of air is trapped between the hand and the powder. Since the powder repels water, the hand remains dry. The beautiful silvery colour of the water against the hand is actually the reflection of light off the water–air interface. (This might be similar to how a fish sees the sky.)
8. SMOKE CANNON
extra elastics (large and long)
Solutions: Concentrated hydrochloric acid (in squirt bottle)
Concentrated ammonia (in squirt bottle)
Place some ammonia and hydrochloric acid at different places on paper towel inside cannon.
Pull back handle and fire.
What is Happening: Ammonia and hydrochloric acid give off fumes which combine to form a “smoke” made of solid ammonium chloride. As the air rushes out of the mouth of the cannon, a region of partial vacuum forms in the region behind the onward–rushing air. This partial vacuum pulls in the surrounding air and forms a doughnut–like “vortex” which is similar to a miniature “tornado”.
9. THE METHYLENE BLUE TRAFFIC LIGHT
500 mL Florence flask with stopper to fit
Chemicals: 300 mL distilled water
8 g potassium hydroxide
10 g dextrose
6–8 drops of methylene blue indicator (indicator solution prepared by dissolving 0.20 g
methylene blue in 100 mL water)
Dissolve 8 g KOH in 300 mL distilled water in 500 mL Florence flask. Just prior to doing the demonstration, dissolve 10 g dextrose in the KOH solution and then add 6–8 drops of methylene blue solution. Swirl the flask and allow it to sit undisturbed until it becomes colourless (about one minute).
To do the demonstration, give the flask a quick shake or two. The blue colour appears again and then slowly fades. This process can be repeated many times.
What is Happening: The oxygen present in the flask oxidizes the methylene blue dye to its blue form. The basic conditions cause the dextrose to reduce the methylene blue dye to its colourless form.
Shaking the flask reintroduces more oxygen into the solution and re-oxidizes the methylene blue to its blue form, continuing the cycle until the oxygen in the flask is used up.
10. SUPERFAST ICE
6–250 mL flasks, with stoppers
2–yellow tote trays
600 mL beaker (to contain scrapings)
In a clean 250 mL flask, dissolve 130 g of sodium acetate in 100 mL distilled water (with heating). Stopper and let cool COMPLETELY UNDISTURBED. Prepare 6 such flasks.
Also have on hand a small beaker with a gram or so of sodium acetate crystals.
Carefully move the flask to where the demonstration will take place – DON’T JAR IT!
Unstopper the flask and, while holding the flask up for the audience to see, add a couple of crystals of sodium acetate.
What is Happening: Sodium acetate has a peculiar crystal structure. When this compound is melted, it is difficult for the molecules to “remember” how to form a crystal again. The solution is “supersaturated” and when a crystal of sodium acetate is added to the liquefied material, the sodium acetate suddenly “remembers” how to crystallise and BINGO!
11. NEON LIGHT AND FLUORESCENT LIGHT
Old neon sign from sign company specialising in neon signs
stands and clamps for neon lights
To perform: Touch one end of the neon light with an operating Tesla coil. A bright red light emission from neon is seen near the metal electrodes; the colour then changes depending on the coating inside the glass tube. (Argon lights give a blue emission.)
Have one person hold the fluorescent tube and another person touch the Tesla coil to the tube, lighting up the tube.
candle and matches
Chemicals: pieces of guncotton
To Perform: throw the guncotton into a flame
What is Happening: The cellulose in the cotton has been treated with nitric acid to make nitrocellulose, which burns rapidly and leaves no residue.
13. AN ORGANIC RAINBOW
500 mL separatory funnel
2–400 mL beaker (one to contain HCl and one to catch liquid from separatory funnel)
1 L beaker to hold ice for cooling HCl
distillation apparatus (optional)
magnetic stirrer, with stir bar
500 mL graduated cylinder or (600 mL beaker and 250 mL graduated cylinder)
10 mL graduated cylinder
250 mL 70% ethanol (175 mL of ethanol + 75 mL of water)
1 mL of tert–butyl chloride
4 mL of universal indicator a few millilitres of 1 M NaOH
Into either a 500 mL graduated cylinder or a 600 mL beaker place 250 mL of distilled water and 250 mL of isopropyl alcohol. Place the container on a magnetic stirrer and begin stirring. Add 1 mL of tert-butyl chloride and stir for another 15 seconds, add 4 mL of universal indicator and stir for another 15 seconds. Finally, add a few drops of 1 M NaoH and continue stirring. The initial blue colour will turn to green, orange and finally red. The process can be repeated by adding some additional NaOH to the reaction mixture.
14. DISSOLVING STYROFOAM
Magnetic stirrer, with stirring bar
2 L beaker
large bag of polystyrene packing chips
400 mL of acetone
To perform: Rapidly stir 400 mL of acetone in the 2 L beaker. As the foam chips are added, they rapidly dissolve. Students are usually amazed at the large volume of chips that can be reduced to a substantially smaller volume.
15. OSCILLATING REACTION: YELLOW AND BLUE
Magnetic stirrer, stir bar, 500 mL beaker, 3–100 mL graduated cylinders, piece of white paper to serve as a backdrop, sticky tape.
Solutions: Solution A = 120 mL 30% hydrogen peroxide added to 300 mL distilled water
Solution B = 1.29 g potassium iodate and 1.5 mL concentrated sulphuric acid added separately to
400 mL distilled water
Solution C = Make a paste of 0.15 g soluble starch in some hot water and add, with
stirring, to 500 mL water. Then add 7.8 g malonic acid and 1.7 g MnSO4•H2O.
Put 50 mL solution A in 600 mL beaker and sit on magnetic stirrer at lowest setting. Then
add 50 mL solution B and then 50 mL solution C.
16. LYCOPODIUM EXPLODER
Lycopodium exploder (see reference or below)
small birthday candle
rubber tubing: 10 mm OD, 150 cm
wide stem Beral pipette
sponge (for clean up)
Chemicals: Bottle of Lycopodium powder
Insert the tubing into the bottom of the plastic bottle. Arrange the candle so the wick is in the centre of the bottle. Use the pipette to place 3–5 “loads” of Lycopodium into the bottle end of the tubing. Make sure the end of the tubing is aimed at the end of the candle and light the candle. Turn off the room lights: take a large breath and blow into the other end of the tubing. A huge fireball erupts above the bottle.
BIG LITTLE SCIENCE CHEMISTRY SHOW: