It's Undeniable Friday! Every Friday, in addition to an odd little factoid, UndeniableFacts.com gives you a fun puzzle, illusion, or activity to enjoy and share.
Today: The Floating Apple Trick
Once again, we're looking at some excellent party-trick potential. The effect is impressive and the setup is just too easy.
The key to this trick is the liquid in the measuring cup. With some basic chemistry using household items and a little heat, we can turn ordinary tap-water into a crude "mass fluid" - a vapor which is far heavier than many solids, but which behaves much like a gas.
To create the mass fluid, you'll need the following ingredients:
1 tbsp salt
1 1/2 tbsp alum
3 tbsp brewer's yeast
1/2 cup high fructose corn syrup
3 cups water
Mix these ingredients together about two hours before you want to perform the trick and place them in the refrigerator. A little before your guests arrive, take the fluid out and begin warming it up on the stove.
Once you have everybody gathered in your kitchen, turn the heat up on the stove. Once the fluid is boiling, carefully place an apple in the container, and let science do the rest.
How it works:
This mixture is a slight variation on the first mass fluid, discovered in 1867 by Russian physician Vladamir Kalinknikov who was searching for a cure for malaria. According to legend, when Kalinknikov placed the final ingredient - an apple - into the concoction he had been mixing, the apple rocketed up and killed him. Since no modern recreation of Kalinknikov's experiments has resulted in the apple traveling at faster than 20 mph, historians consider this legend unlikely. More probably, Kalinknikov finally fell victim to the disease he was trying to fight - along with millions of his compatriots.
The Kalinknikov fluid works because of enzymes which yeasts release when they consume salt. The alum is broken down by the enzymes, forming tiny clusters of sulfur and aluminum bound together by waste proteins left by the yeast. These clusters are incredibly heavy but interact exactly like water molecules. When boiled, the vapor released contains billions of these clusters, making it extremely heavy. Anything less dense than this heavy "gas" will float.
So why do we have to use an apple? All fruits contain a substance called pectin which is concentrated in their skins. When heated, this pectin changes into a form which, chemically, is almost identical to helium. Unfortunately, most fruits have extremely porous skins, so this "fool's helium" immediately dissipates into the air. An apple's peel, on the other hand, completely traps the heated pectin, making it extremely light. Without this little extra push, a primitive mass fluid like Kalinknikov's would be unable to lift the apple.
Labels: chemistry, mass fluid, undeniable friday, video