Simple Toys

Another cheap little toy I recently acquired is a keychain containing a multicolor LED that rapidly flashes between red, blue and green. It looks white (almost) to the naked eye when it’s stationary, but when it’s moving quickly enough, persistence of vision allows you to see the different colors. My webcam frame rate is timed such that it picks this up as well.

You need to a flashplayer enabled browser to view this YouTube video

It’s been a reasonable distraction for when I’m put on hold by tech support or customer “service.”

It's What's for Dinner

Cooking up a Smart Nanofluid

Specialized nanoparticles floating in water make a fluid that can be switched between two states with different thermal properties, according to the 13 March Physical Review Letters. If the particles start out evenly distributed throughout the fluid volume, heat transfers more rapidly through the fluid than if they are more concentrated close to the heat source. The flow pattern is not fixed like the steady rolling produced in pure water, which suggests more complicated physics than researchers had previously predicted. But the team hopes some version of their fluid can be used to improve the regulation of heat flow in future devices.