EKSPERIMEN
1.
DRY ICE FOG
Time Required: Instantaneous
Here's How:
1.
This is so easy! Add chunks of dry ice
(solid carbon dioxide) to hot water in a styrofoam or other insulated
container.
2.
The fog will sink to the ground. You may use
a fan on a low setting to move your 'smoke'.
3.
The water will cool, so you will need to
refresh the hot water to maintain the effect.
4.
Room temperature matters - you will get the
most fog in a cool room. Have fun!
Tips:
1.
Dry ice is cold enough to give frostbite.
Wear protective gloves when handling it.
2.
Larger chunks of dry ice will last longer
than smaller ones.
3.
Be aware that extra carbon dioxide is being
added to the air. Under some circumstances, this can present an asphyxiation
hazard.
4.
Sometimes inexpensive dry ice machines are
available, otherwise check party supply stores and shipping companies for
availability.
5.
Keep dry ice away from children, pets, and
fools! Adult supervision is required.
What You Need
- Dry Ice (Carbon
Dioxide)
- Hot Water
- Insulated
Container
2.
SMOKE
BOMB
The smoke bomb you
would purchase from a fireworks store usually is made from potassium chlorate
(KClO3 - oxidizer), sugar (sucrose or dextrin - fuel), sodium bicarbonate
(otherwise known as baking soda - to moderate the rate of the reaction and keep
it from getting too hot), and a powdered organic dye (for colored smoke). When
a commercial smoke bomb is burned, the reaction makes white smoke and the heat
evaporates the organic dye. Commercial smoke bombs have small holes through
which the smoke and dye are ejected, to create a jet of finely dispersed
particles. Crafting this type of smoke bomb is beyond most of us, but you can
make an effective smoke bomb quite easily. There are even colorants you can add
if you want to make coloured smoke. In fact, this type of smoke bomb was used
to craft the world’s biggest smoke bomb! Let's start out with instructions for
the easiest/safest type of smoke bomb you can make:
Smoke Bomb Materials
·
sugar (sucrose or table
sugar)
·
potassium nitrate, KNO3,
also known as saltpeter (buy it online or you can find this at some garden
supply stores in the fertilizer section, some pharmacies carry it too)
·
skillet or pan
·
aluminum foil
How to Make a Smoke Bomb
1.
Pour about 3 parts
potassium nitrate to 2 parts sugar into the skillet (5:3 ratio is also good).
Measurements don't need to be exact, but you want more KNO3 than sugar. For
example, you can use 1-1/2 cups KNO3 and 1 cup sugar. If you use equal amounts
of KNO3 and sugar, your smoke bomb will be harder to light and will burn more
slowly. As you approach the 5:3 KNO3:sugar ratio, you get a smoke bomb that
burns more quickly.
2.
Apply low heat to the pan.
Stir the mixture with a spoon using long strokes. If you see the grains of
sugar starting to melt along the edges where you are stirring, remove the pan
from the heat and reduce the temperature before continuing.
3.
Basically you are
carmelizing sugar. The mixture will melt and become a caramel or chocolate
color. Continue heating/stirring until the ingredients are liquefied. Remove
from heat.
4.
Pour the liquid onto a
piece of foil. You can pour a smaller amount onto a separate piece, to test the
batch. You can pour the smoke bomb into any shape, onto an object, or into a
mold. The shape and size will affect the burning pattern.
5.
If you aren't going to
clean your skillet immediately, pour hot water into the pan to dissolve the
sugar (or else it will be harder to clean). Clean up any residue you may have
spilled out of the pan, unless you want mini-smoke bombs on your stovetop.
6.
Allow the smoke bomb to
cool, then you can peel it off the foil.
Now that you've made
your smoke bomb, it's time to light it...
3.
ELEPHANT
TOOTHPASTE
The elephant
toothpaste chemistry demonstration is a dramatic demo which produces copious
amounts of steaming foam that sort of looks like the toothpaste an elephant
might use. Here's how to set up this demonstration and a look at the reaction
behind it.
Elephant Toothpaste
Materials
- 50-100 ml of
30% hydrogen peroxide (H2O2) solution
- saturated
potassium iodide (KI) solution
- liquid
dishwashing detergent
- food colouring
- 500 mL
graduated cylinder
- splint
(optional)
Safety
Wear disposable
gloves and safety glasses. Oxygen is evolved in this reaction, so do not
perform this demonstration near an open flame. Also, the reaction is
exothermic, producing a fair amount of heat, so do not lean over the graduated
cylinder when the solutions are mixed. Leave your gloves on following the
demonstration to aid with cleanup. The solution and foam may be rinsed down the
drain with water.
Procedure
1.
Put on gloves and safety glasses. The iodine
from the reaction may stain surfaces so you might want to cover your workspace
with an open garbage bag or a layer of paper towels.
2.
Pour ~50 mL of 30% hydrogen peroxide
solution into the graduated cylinder.
3.
Squirt in a little dishwashing detergent and
swirl it around.
4.
You can place 5-10 drops of food coloring
along the wall of the cylinder to make the foam resemble striped toothpaste.
5.
Add ~10 mL of potassium iodide solution. Do
not lean over the cylinder when you do this, as the reaction is very vigorous
and you may get splashed or possibly burned by steam.
6.
You may touch a glowing splint to the foam
to to relight it, indicating the presence of oxygen.
Variations of the
Elephant Toothpaste Demonstration
- You can add 5
grams of starch to the hydrogen peroxide. When the potassium iodide is
added, the resulting foam will have light and dark patches from the
reaction of some of the starch to form triiodide.
- You can use
yeast instead of potassium iodide. Foam is produced more slowly, but you
can add a fluorescent dye to this reaction to produce elephant toothpaste
that will glow very brightly under a black light.
- You can colour
the demonstration and make it into an Elephant
Toothpaste Christmas Tree for the holidays.
- There is also a kid-friendly
version of
the elephant toothpaste demo that is safe for hands.
Elephant Toothpaste
Chemistry
The overall equation
for this reaction is:
2 H2O2(aq)
→ 2 H2O(l) + O2(g)
However, the decomposition
of the hydrogen peroxide into water and oxygen is catalzyed by the iodide ion.
H2O2(aq)
+ I-(aq) → OI-(aq)
+ H2O(l)
H2O2(aq)
+ OI-(aq) → I-(aq) +
H2O(l) + O2(g)
The dishwashing
detergent captures the oxygen as bubbles. Food colouring can colour the foam.
The heat from this exothermic reaction is such that the foam may steam. If the
demonstration is performed using a plastic bottle, you can expect slight
distortion of the bottle from the heat.
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