Covert radio pen with bone conduction speaker

https://www.patreon.com/AppliedScience ---- Donate here!
I built a tiny radio into a ballpoint pen that allows the user to hear audio by casually biting the pen.

How a horn amplifies sound (hint: Impedance matching)

A horn-shaped speaker is louder than an equivalent speaker without the horn.  This fact doesn't violate physics because the horn is acting as a matching device between the speaker and the air around it.

Photo Credit for phonograph: Norman Bruderhofer,  Collection of John Lampert-Hopkins

Chocolate gun dispenses edible molten chocolate

I modified a standard hot glue gun to dispense molten semi-sweet chocolate. This is great for decorations and gingerbread houses.

Obeying the law (of physics)! Kinetic energy and momentum explained

In my video on the Crookes Radiometer, I showed that the devices spins because of a thermal gas effect -- not the force of photons hitting the vanes.  In the comments section, someone asked about kinetic energy and how incoming photons impart force to the rotor.  This video is a more complete answer to that question.

Encode information in fire!

A burning strip of carefully cut flash paper can encode information, which is then read by an optical sensor.  I'd like to determine if it's possible to perform computations with nothing but flash paper -- using the shape of the paper as data and program, and the flame as the readout.

Hamamatsu S7815 photodiode -- might be discontinued:
https://www.google.com/#q=hamamatsu+s7815

Harvard Infofuse project:
http://scienceblogs.com/notrocketscience/2009/05/26/the-infofuse-encoding-messages-using-colourful-fire/
http://gmwgroup.harvard.edu/research/index.php?page=17
http://dash.harvard.edu/bitstream/handle/1/12967828/84853636.pdf?sequence=1

Source for flash paper and flash cotton:
http://www.dreamlandmagic.com/flash-paper.html

Subscribe to my channel here: https://www.youtube.com/user/bkraz333