Lithium sheet metal and zirconium powder

I found some interesting materials at a local fleamarket (http://www.electronicsfleamarket.com/): a canister of lithium sheet metal, and a bottle of fine zirconium powder (325 mesh). The zirconium is stored under water since the dry power can self-ignite, or may be ignited by static electricity or shock. Confusingly, the MSDS sheets say that dry zirconium powder must not be allowed near water, but http://www.blogger.com/img/blank.gifif it is to be stored, it must be completely submerged in water. I carefully dried a very small amount, and sprinkled it over a flame.

If you know of something interesting to do with these chemicals, please let me know.

Making Pop Rocks candy at home

Here I show how I made gassified candy (eg Pop Rocks) in my home shop. The basic procedure is to heat sugar water up to 280*F, carbonate it with 600 psi CO2 and vigorous mixing, then cool the mixture while it is still under pressure. After the mixture has solidified, rapid depressurization causes the candy to burst apart into small fragments. Each fragment has lots of tiny CO2 bubbles embedded in it. When placed on the tongue, the bubbles burst open as the candy dissolves and a popping sensation is felt.

The main difficulty is building a high-pressure chamber that allows precise temperature control as well as thorough mixing of its contents while under pressure. I've built something that meets these requirements, and I've finally made a batch of candy that would pass as Pop Rocks, but they are pretty weak. I still need to adjust the temperature and mixing times to get a better product.

Link to recipe: http://www.exploratorium.edu/cooking/candy/recipe-lollipops.html

Power strip failure analysis

A brand-new power strip emitted a loud pop and left a soot mark on my friend's hand when he plugged it into the wall. No devices were attached to the power strip. I decided to take the thing apart to see what failed. The circuit breaker in the household electrical system did NOT trip during this event.

My guess is that a very fine piece of wire bridged the neutral and hot terminals on the switch. When power was applied, the whisker vaporized.

How a liquid lens works (electrowetting)

A liquid lens works by changing the shape of a water drop by creating an electrostatic field that pulls on the water molecules. I show how water can be affected by a high voltage supply and an electrostatically charged comb.

The process by which the droplet changes shape is known as electrowetting.

Projector HID arc light mounted into a desk lamp

I combined the High Intensity Discharge bulb and power supply from an old LCD with a desk lamp to create a 270W spotlight. I bypassed the power supply's interlocks and shorted an optocoupler to cause the power supply to always turn the lamp on when AC power is applied. I used an inline power switch to control the device. The desk lamp's existing wiring is able to withstand the high starting voltage of the HID lamp (probably a few KV). Once the arc strikes, the voltage is much lower and the current much higher.