Dry ice, or Cardice – as British researchers call it, is a solid form of carbon dioxide. When carbon dioxide is cooled below temperatures of -78.5 degrees centigrade, the gas gets directly frozen into a solid form. -78.5 degrees centigrade is extremely cold, and handling dry ice without proper protection can be very dangerous – could cause frostbite / burns. The point being, it’s extremely cold.
Since it’s too cold compared to something at room temperature, even everyday objects at room temperature can make it vaporize. A simple metal coin at room temperature would feel like a hot pan to dry ice. So, when a coin is shoved into a piece of dry ice, it creates a funny sound, just like water would, on a very hot pan; or, you could say the sound be very much like a hot metal ball being dropped into a cold bath of water (the temperature difference being much less in this case, of course).
This is how it works: The metal piece at room temperature vaporizes some amount of carbon dioxide from the piece of dry ice when it comes in contact. There’s a pressure difference (Bernoulli’s principle) associated with this process and the gas tries to escape. This makes the metal vibrate very fast, creating that funny sound. This is how it sounds…
Metals work best because they have a good thermal conductivity. For the sake of trying it out yourself, if you have a piece of dry ice lying unused, you could dip a spoon in hot water and make it touch the piece of dry ice. A slightly warmer spoon will probably give you a better effect. And then the spoon will be singing…
In the year 2003, a group of researchers headed by James Tour at Rice university designed and synthesized a series of organic molecules that they thought would get kids interested in chemistry.
These organic molecules resembled human figures and were named Nanoputians – A portmanteau of nanometer (a unit of length used to measure extremely tiny distances) and Lilliputian (the tiny human-like fictional characters from Gulliver’s travels).
The synthesized nanokid molecule basically consisted of two benzene rings and a couple of carbon atoms for its body. For the limbs acetylene units ending in an alkyl group were used. The upper body and the lower part were both created separately, and were joined using Palladium and Copper compounds. Here’s how…
The head of a basic Nanoputian was a 1,3-dioxolane ring. However, after using an advanced microwave irradiation technique, the team created a couple of other variants (called Nanoprofessionals) to replace the Nanokid’s head. Here is what the series of head variants that were created. As if that wasn’t enough, there is a nano ballet dancer too.
Now, in the scientific community, James and his team are better known for synthesizing a much more cooler thing – A nanocar. The nanocar they synthesized was a single molecule car which could be pushed around using a scanning tunnelling microscope. And another one which is fuelled by light!
There are a couple of other cool molecular machines they’ve made too.
Steve Spangler Never ceases to amaze me. Once again I found this old video of him on the Ellen show. These are a few experiments he does on the stage…
- Lights a tube light with his bare hands and Ellen’s.
- A transparent liquid suddenly instantly changes colour.
- Blows the hydrogen and oxygen mixture on Ellen’s hand.
- And makes someone from the audience walk across the table on a non newtonian fluid.
Steve doesn’t exactly explains what happens there, but the second experiment is my favourite. It is the one in which he asks Ellen to pour two transparent liquids into each other and mix them well. Then Ellen waits for a few seconds and the liquid instantly turns into an ink like colour.
The magical effect is actually a chemical reaction known as the Landolt Clock Reaction. It actually involves 3 different solutions (read about them). The reaction happens quicker once the mixing starts and leads to a third reaction which happens immeasurably fast. It’s totally instantaneous and thus the transparent solutions turn into a bluish black iodine starch complex. As steve’s website puts it…
The sudden change from a colorless solution to the blue-black solution is the result of four sequential reactions. First, the bisulfite ions (HSO3-) reduce some of the iodate ions (IO3-) to form iodide ions (I-). Next, the iodide ions (I-) are oxidized by the remaining iodate ions (IO3-) to form triiodide ions (I3-). The solution now consists of triiodide ions (I3-) and soluble starch. In the third reaction, the triiodide ions (I3-) get reduced by the bisulfite ions (HSO3-) to become iodide ions (I-). That continues until all of the bisulfite has been consumed. Finally, the triiodide ions and starch combine to form the dark blue-black starch complex that looks like ink.
See more at: SteveSpanglerScience