Nigel Baldwin | Luminol and a magnesium diver C0203 @nigelbaldwin3184 | Uploaded July 2020 | Updated October 2024, 3 hours ago.
High School Chemistry
A fun demonstration using luminol and a small piece of magnesium.
The whole procedure can be completed in 5 to 10
minutes.
Equipment and chemicals
10ml glass measuring cylinder
2 plastic dropping pipettes
50 - 100mg of solid luminol (a small amount of powder on the tip of a spatula will suffice)
3ml sodium hydroxide solution, 2M
2ml hydrogen peroxide solution, 6% commercial solution
3ml of sucrose solution (60g sucrose in 45ml water)
Superglue
A small neodymium magnet, 12mm diameter (several may be used in a stack)
a few milligrams of solid manganese dioxide
2ml distilled water
5 - 10ml iron (III) chloride solution, 0.1M
spatula
scissors
Procedure
Stage 1
To a 10ml measuring cylinder add the following three substances
3ml of sodium hydroxide, 2M
2 ml hydrogen peroxide, 6%
50 to 100mg of solid luminol
Mix the three substances by repeatedly drawing up into and then squirting out of a plastic dropping pipette. Approximately 5ml of a pale yellow solution is obtained.
Add 3ml of concentrated sucrose solution. This can be made accurately by dissolving 60g of sucrose in 45ml of water or alternatively, one could improvise by adding several spatula measures of sucrose to a few mls of warm water.
Use the same sucking up and squirting out technique with the dropping pipette to mix the sucrose solution and the yellow luminol solution thoroughly.
Stage 2
Separately, cut a short piece of magnesium ribbon, approx. 1cm in length. Arms and legs can be cut into the magnesium to produce a diving figure if desired.
Add a small blob or two of superglue to the magnesium at any chosen locations.
Dip the magnesium and wet glue into a few milligrams of manganese dioxide solid, such that the black powder sticks to the glue and allow to dry for a minute.
Drop the magnesium into 5ml of 0.1M iron (III) chloride solution in a test-tube. The magnesium will fizz and a displacement reaction occurs.
Stage 3
Slowly add 2 to 3ml of distilled water to the luminol and sucrose mixture in the measuring cylinder by running the water slowly down the side of the cylinder. The water, being lower in density, will form a layer on the top.
Using a pair of tweezers take the magnesium out of the iron(III) chloride solution and drop into the measuring cylinder.
The magnesium will be attracted to a small neodymium super magnet, 12mm diameter held outside of the measuring cylinder through the glass wall. Use the magnet pull the magnesium down into the luminol sucrose layer. On release the magnesium will bob back up into the upper layer and may release a stream of blue bubbles on rising up.
This can be repeated over and over.
Additionally, drops of 0.1M iron (III) chloride solution can be added to the top of the mixture in the measuring cylinder. Spectacular flashes of blue light can be observed.
Apologies for the out of focus video image and the noise of some workmen drilling outside the laboratory.
I hope to upload a better quality video clip of the demonstration soon.
High School Chemistry
A fun demonstration using luminol and a small piece of magnesium.
The whole procedure can be completed in 5 to 10
minutes.
Equipment and chemicals
10ml glass measuring cylinder
2 plastic dropping pipettes
50 - 100mg of solid luminol (a small amount of powder on the tip of a spatula will suffice)
3ml sodium hydroxide solution, 2M
2ml hydrogen peroxide solution, 6% commercial solution
3ml of sucrose solution (60g sucrose in 45ml water)
Superglue
A small neodymium magnet, 12mm diameter (several may be used in a stack)
a few milligrams of solid manganese dioxide
2ml distilled water
5 - 10ml iron (III) chloride solution, 0.1M
spatula
scissors
Procedure
Stage 1
To a 10ml measuring cylinder add the following three substances
3ml of sodium hydroxide, 2M
2 ml hydrogen peroxide, 6%
50 to 100mg of solid luminol
Mix the three substances by repeatedly drawing up into and then squirting out of a plastic dropping pipette. Approximately 5ml of a pale yellow solution is obtained.
Add 3ml of concentrated sucrose solution. This can be made accurately by dissolving 60g of sucrose in 45ml of water or alternatively, one could improvise by adding several spatula measures of sucrose to a few mls of warm water.
Use the same sucking up and squirting out technique with the dropping pipette to mix the sucrose solution and the yellow luminol solution thoroughly.
Stage 2
Separately, cut a short piece of magnesium ribbon, approx. 1cm in length. Arms and legs can be cut into the magnesium to produce a diving figure if desired.
Add a small blob or two of superglue to the magnesium at any chosen locations.
Dip the magnesium and wet glue into a few milligrams of manganese dioxide solid, such that the black powder sticks to the glue and allow to dry for a minute.
Drop the magnesium into 5ml of 0.1M iron (III) chloride solution in a test-tube. The magnesium will fizz and a displacement reaction occurs.
Stage 3
Slowly add 2 to 3ml of distilled water to the luminol and sucrose mixture in the measuring cylinder by running the water slowly down the side of the cylinder. The water, being lower in density, will form a layer on the top.
Using a pair of tweezers take the magnesium out of the iron(III) chloride solution and drop into the measuring cylinder.
The magnesium will be attracted to a small neodymium super magnet, 12mm diameter held outside of the measuring cylinder through the glass wall. Use the magnet pull the magnesium down into the luminol sucrose layer. On release the magnesium will bob back up into the upper layer and may release a stream of blue bubbles on rising up.
This can be repeated over and over.
Additionally, drops of 0.1M iron (III) chloride solution can be added to the top of the mixture in the measuring cylinder. Spectacular flashes of blue light can be observed.
Apologies for the out of focus video image and the noise of some workmen drilling outside the laboratory.
I hope to upload a better quality video clip of the demonstration soon.
