By NTP^2 Admin | September 04, 2011 at 02:13 PM EDT | No Comments
Thank you everyone who stopped at the NTP^2 booth over the past couple of days. If you missed it, we demonstrated the Rubens' Tube and, for the CSE scavenger hunt booth in front of Cofffman, deflagration. At the Celebrate U fair we also showed off our electroshock box and we made ice cream with nitrogen.
Here are some quick descriptions of these demos.
This device demonstrates the principle of flyback transformers. When the button is depressed, a low voltage current is fed through the primary coil of the transformer, creating a magnetic field. When the current flow is stopped by releasing the button, the magnetic field collapses suddenly. This induces a high voltage, low current pulse in the secondary winding, which can be felt as a small electrical shock.
Deflagration and Methyl Borate
Deflagration is a special subset of combustion where the fuel and oxidizer are mixed homogeneously. This allows the reaction front to propagate through the mixture very quickly. This is the same type of reaction found in internal combustion engines.
Our fuel (methanol) normally burns with very little color, but when mixed with boric acid, it creates methyl borate ( B(OCH3 ) 3). When electrons in the boron atoms ionize, then drop down to lower orbitals, photons are released in the 530 nm wavelength, causing a green flame.
Liquid Nitrogen Ice Cream
To create the smooth and delicious texture of ice cream, the ice crystals must be very small. Liquid nitrogen, which boils at -196 °C, creates a large temperature gradient, causing the water to freeze before large ice crystals can grow.
This is a visualization of standing waveforms. A speaker creates areas of high and low pressure within the tube, forcing different amounts of propane through the holes. The valleys and peaks correspond to the nodes and antinodes of the audio.