Experiment: Mercury Beating Heart

This old post serves as the Video Companion to  this video.

This is an extremely cool demonstration of electrochemistry involving one of my favorite elements - mercury. It's a shame that it's so toxic, otherwise it would be incredibly fun to play with. The setup for this experiment is simple, but very difficult to get it to work in practice. A droplet of elemental mercury is placed in a solution of an electrolyte and a strong oxidizer. Next a piece of iron is brought near the drop, which then starts to oscillate and looks like a beating heart.

Get Useful Components from a Lantern Battery

Here's a cheap, easy way to get three very useful items for your own experiments - carbon, zinc, and manganese dioxide. All you need is a 6V lantern battery and a few common tools. You want to make sure you buy a carbon-zinc type battery. If it says "heavy duty" or "ultra heavy duty" on the sticker, then you're good to go. If it says alkaline anywhere on it, this procedure will not work as that uses a different battery chemistry. I used an Everready Heavy Duty battery, which didn't mention carbon-zinc, but I've seen this done before with this battery type so I knew it would work.

Experiment: Vanadium Pentoxide Thermite

Here's a quick one. This thermite was a 2.02:1 mix of V2O5:Al powder. Vanadium pentoxide is a (fairly toxic) orange powder, and it made a sandy colored thermite mix. It reacts via the equation

10Al + 3V2O5 -> 5Al2O3 + 6V

I was only able to get one good picture of the actual reaction because it happens so fast - its more like a small explosion! It produced some very bright white sparks, a color that the camera didn't capture too well. I thought it was going to start a brush fire afterward, as you can see in the last two photos by all the fire! I was able to find some small pieces of vanadium in the aftermath - a lot of which was lying in the sand nearby. Some pieces had some tarnish on them, giving them a neat iridescent purpleish shine.

Experiment: Tin Oxide Thermite

Another thermite composition - 4.19:1 SnO2:Al by weight, with about 25g total thermite. I already had tin samples for my collection, but every thermite produces a different reaction so I wanted to try it out. I wasn't disappointed. This one produced a lot of smoke and some bright sparks, following the reaction
4Al + 3SnO2 -> 2Al2O3 + 3Sn
I recovered a lump of tin caked in alumina slag that I could not easily remove since tin is so soft. I melted the piece in a crucible and was able to pour off some (relatively) pure tin that was nice and shiny. As you can see in the last picture I recovered almost 4g of tin, which was about a 20% yield.

Experiment: Silver Tree

This old post serves as a video companion to this video on my YouTube channel.

This is an experiment I've had since the very beginning of my home laboratory, but for some reason I never got around to doing it. This is a single replacement reaction that precipitates pure silver metal out of a solution of silver nitrate in the presence of solid copper metal. The silver grows on the copper in very fine, hairlike crystals. After a while, they become thick enough to look almost like clouds (see the photos below). The reaction goes fairly quickly at first then slows down - mine appeared to be done after about 30 minutes, but I left it to stew for a few hours to make sure I got all the silver out of solution.