Anything that glows…

Halloween season is a bit mad in this science filled house as you may have guessed by now.  There have been more experiments than dinners in the kitchen the past week… we have been repeating old favourites, modifying others and trying out new ones.. and all because it is Halloween.

We love things that glitter and glow and this time of years allows us to really indulge this side of science.  I thought I would share some new favourites with you here, in case anyone wants to add some glowing fun to their Halloween parties or games!

Glowing lava lamps:

We love making lava lamps but made a few modifications to add a bit more glow to this favourite!

You will need:

An empty plastic bottle or a clear plastic cup
Water
Vegetable oil
A funnel
Florescent paint (or glow in the dark paint*)
Alka Seltzer (or similar antacid tablets)
A UV light (also called a black light) if possible

What to do:

1. Put a small amount of water (about an inch or two) in the bottom of the plastic bottle or cup.
2. Add some fluorescent paint to the water and mix.
3. Using the funnel pour the vegetable oil into the bottle, filling almost to the top.
4. You will see that the water and oil settle into two layers, with the water at the bottom.
5. Break up the Alka Seltzer tablets into smaller piece, and, if you have a UV light, turn it on and turn off the regular light.
6. Add some pieces of the Alka Selzer tablet to the bottle to start off your lava lamp.
7. Once the bubbles stop rising you can add more tablets to keep the lava lamp going.

We added fluorescent paint to water in each cup and then we mixed it in

Then we added a layer of vegetable oil to each

Then we turned on our UV light…

…And turned off all other lights. We added the Alka Seltzer and watched in delight!

You get a better idea from our videos…

So what is happening?

The Alka Seltzer tablets drop to the bottom of the bottle and dissolve in the water.  These tablets contain an acid (citric acid) and a base/alkali (Sodium hydrogen coarbonate) in powder form.  When these dissolve in water the acid and the alkai start to react together and form carbon dioxide gas.  This gas forms bubbles with the water.  The bubbles are lighter than the water and oil so they travel up the bottle to the top.  Once they reach the air they burst and the water droplet is now heavier than the oil and drops back down to the bottom of the bottle again.

Notes:

We tried both flourescent and glow in the dark paints for this experiment.  We found the flourescent paint worked best, but if you have a good glow in the dark paint feel free to try this out with the lights off!

This is our fluorescent lava lamp in daylight… still pretty cool we think!

If you do not have a UV light then try this experiment in the daytime with plenty of sunlight. 

The fluorescent paint is still very bright and gives a pretty cool effect.