Difference between revisions of "Chemical demonstrations"
| Line 32: | Line 32: | ||
[http://youtu.be/KWJpKNQfXWo video: iodine clock demonstration and theory] | [http://youtu.be/KWJpKNQfXWo video: iodine clock demonstration and theory] | ||
| + | |||
===Chameleon=== | ===Chameleon=== | ||
5 vivid color changes in a row while the reaction passes through the many different oxidation states of manganese. | 5 vivid color changes in a row while the reaction passes through the many different oxidation states of manganese. | ||
[https://www.youtube.com/watch?v=kKlXe2mrnHQ Video: Chameleon demonstration] | [https://www.youtube.com/watch?v=kKlXe2mrnHQ Video: Chameleon demonstration] | ||
| + | |||
==Light emission== | ==Light emission== | ||
===Fluorescent pH indicator=== | ===Fluorescent pH indicator=== | ||
Pyranine, present in highlighter fluid, will fluoresce different colors in different levels of acidity. | Pyranine, present in highlighter fluid, will fluoresce different colors in different levels of acidity. | ||
| + | |||
===Smash-glow crystals=== | ===Smash-glow crystals=== | ||
Sugar will emit ultraviolet light when crushed. When a fluorescent dye such as methyl salicylate is used, the fluorescence is made much brighter. | Sugar will emit ultraviolet light when crushed. When a fluorescent dye such as methyl salicylate is used, the fluorescence is made much brighter. | ||
| + | |||
==Miscellaneous== | ==Miscellaneous== | ||
| Line 55: | Line 59: | ||
[https://www.youtube.com/watch?v=AP6rTJi59NM Video: carbon snake demonstration] | [https://www.youtube.com/watch?v=AP6rTJi59NM Video: carbon snake demonstration] | ||
| + | |||
==Alkali metals== | ==Alkali metals== | ||
===In the presence of water=== | ===In the presence of water=== | ||
| Line 65: | Line 70: | ||
[[Rubidium]] and [[caesium]] will explode. | [[Rubidium]] and [[caesium]] will explode. | ||
| − | https://www.youtube.com/watch?v=uixxJtJPVXk | + | [https://www.youtube.com/watch?v=uixxJtJPVXk Video: Alkali metals reaction with water] |
==See also== | ==See also== | ||
Revision as of 11:03, 1 March 2020
Chemical demonstrations that are amusing or impressive to watch.
Contents
Energetic materials
Explosive decomposition of Para-nitroaniline
Para-nitroaniline explodes, leaving an impressive mount of carbon behind under the attack of hot concentrated sulfuric acid.
Video: P-nitroaniline's decomposition demonstration
Mercury thiocyanate ("Pharaoh's snake")
Mercury(II) thiocyanate burns forming residues looking like tentacles growing from the ground.
Video: mercury thiocyanate's combustion demonstration
Ammonium dichromate ("Volcano")
When ammonium dichromate burns, it looks like an erupting volcano.
Video: ammonium dichromate's combustion demonstration
Iodine and aluminium
When aluminium and iodine are combined in the presence of a small amount of water, they react to produce thick purple smoke and leaves a metallic coating on the glass.
Video: Iodine and aluminium demonstration
Color changes
Briggs-Rauscher oscillator
Very pronounced and rapid color changes repeating again and again and again.
Video: iodine oscillator demonstration
Iodine clock reaction
Colorless solutions becoming deep blue/black almost instantaniously after a small delay.
video: iodine clock demonstration and theory
Chameleon
5 vivid color changes in a row while the reaction passes through the many different oxidation states of manganese.
Video: Chameleon demonstration
Light emission
Fluorescent pH indicator
Pyranine, present in highlighter fluid, will fluoresce different colors in different levels of acidity.
Smash-glow crystals
Sugar will emit ultraviolet light when crushed. When a fluorescent dye such as methyl salicylate is used, the fluorescence is made much brighter.
Miscellaneous
Elephant toothpaste
The rapid decomposition of hydrogen peroxide with a catalyst (usually potassium iodide or yeast) in soapy water generates a huge amount of hot foam due to oxygen generation.
Video: Elephant toothpaste demonstration
Carbon snake
Materials needed: granular sugar and concentrated (98%) sulfuric acid, acid resistant gloves
Procedure: Pour concentrated sulfuric acid directly onto sugar.
Result: a tower of porous carbon forms after a delay period.
Video: carbon snake demonstration
Alkali metals
In the presence of water
Lithium will effervesce strongly
Sodium will do so more strongly and may catch fire
Potassium catches fire
Rubidium and caesium will explode.
Video: Alkali metals reaction with water
