A Flashing Blue Light

Magnetic stirrer, 500-mL glass jar, three 200-mL beakers, magnetic bar, safety glasses, protective gloves. 

Sodium iodate NalOs, 1 mol/L H2SO4, malonic acid HOOCCH2COOH, manganese(II) sulfate MnS04 H2O, soluble starch, 10 % H2O2 solution, distilled water. 

5 g sodium iodate and 10 mL 1 mol/L H2SO4 in 100 mL of distilled water. Solution B 

The three colorless solutions are poured simultaneously into the glass jar and stirred well. After a short time the oscillation between blue and colorless starts. 

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Oh, what is it six-year-old Cliff suddenly exclaims, his blue eyes wide and focused in front of him. We all turn and see on the lake a flash of light like a star or a firecracker exploding, then another and another until there are hundreds of patches of twinkling stars improbably skimming the surface of the water, moving from one place to the next in a rhythm that is their own, impossible to predict. 

In spectrophotometric analyzers, interference filters are selected for desired wavelengths, as determined from the spectral relationship curves. Photodetectors are least sensitive in the blue end of the spectrum. This can be dealt with by using prefilters or narrow spectral ranges, which are calibrated for more sensitivity. Improvements in spectrophotometers include a flashed xenon light source with dual-beam measurement. Dual-beam machines measure the spectrum of both the light source and the reflected light for each measurement. 

Observation A flash of light can be observed when the sodium is pressed into the mercury, a dull grey solid matter results which is quite brittle and which can be broken sodium amalgam. In the reaction with water, small bubbles (hydrogen) occur and a solution is produced that colors the indicator paper blue sodium hydroxide solution. Liquid mercury remains after some time, it can be put back into the container. 

Above a critical pressure (about 8 torr at 180 °C falling to about 2 torr at 200 °C) diethyl peroxide explodes spontaneously, emitting a flash of blue light. This explosion, which is preceded by an induction period... 

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