The surface tension is one of the most interesting effects we can observe in a mixture of liquids of different densities. A fun and decorative way to see this effect is with the famous psychedelic or lava lamps, which were invented by Edward Craven Walker in the 1960s. Next, we will see how to build an attractive lava lamp in just a few steps and with easy-to-find materials.
- Distilled water.
- Baby oil (Transparent).
- Vegetable (oil) colouring.
- Colourless paraffin.
- A heat-resistant glass bottle (Pyrex or Kimix)
- A spring that covers the entire bottom of the bottle.
- A metal can with the same width as the bottle.
- A light bulb of about 40 watts.
- Metal cover.
Assembling the base
To make the base of our lava lamp, we make a hole in the base of the can through which we are going to pass the wires of the socket of our lava lamp. lamp. Then, we fix the socket to the base with glue and make a plaster preparation, which we pour into the tin so that the lamp is fixed and at the same time a counterweight is created, so that the base can support the lamp. Let the plaster dry for at least a couple of hours (make sure that the plaster does not go over the socket). After the plaster has dried, place the bulb inside the socket.
The first step is to clean the bottle thoroughly with water and dishwasher, to prevent lava from sticking to it. Let the bottle dry and when it is completely dry, insert the spring which should be at the bottom of the bottle as a ring that covers the entire surface of the bottom. This spring will act as a promoter in the heat exchange and will promote the breaking of the surface tension.
Melt the paraffin using a water bath. Once melted, add two tablespoons of the baby oil to the liquid paraffin and mix the components together. Then, add a little baby oil into the bottle (about 2 cm) and shake the bottle so that the oil remains all over the inside surface.
Take the mixture of paraffin and oil and add vegetable colouring and mix. Pour the mixture into the bottle with the help of a funnel, taking care that it does not spill over the walls of the bottle. bottle. The amount of mixture to be added will be approximately 4 cm, then let the mixture solidify inside the bottle.
The next step is to add distilled water about halfway up the bottle. Next, add a little baby oil and then more distilled water until you reach about 4 cm from the top of the bottle. bottle. Cover the bottle with the metal cap and let the paraffin mixture harden completely, at least 12 hours.
After the 12 hours, we put the bottle in the refrigerator for at least an hour (to dissipate any traces of air in the paraffin) and our lava is ready. We place the bottle on the base and light the lamp. As this is the first time, it may take a couple of hours to see the effect.
How it works
When the aqueous medium of the lava lampThe surface tension between the fluids inside, creating bubbles that float on the aqueous medium, offering a very attractive optical effect.