My Homemade Lava Lamp Experiment

Aim: To create a lava lamp effect by using readily availiable ingredients

Hypothesis: Two insoluble mixtures, such as an oil based mixture and a water based mixture, with very similar densities should act in the way that a lava lamp works when heated. The heavier liquid should rise to the top as it heats up, and sink back down to the bottom when in cools.

Method:

Equipment Setup:

*All lamps are being created in glass bottles with a 750mL capacity, and are being heated over a 40 watt globe in the base of a commercial lava lamp. A one inch air gap is being left in the top of every lamp. Some lamps are coloured with food dyes.

Lava Lamp Number 1: The "lava" in this lamp is made from raw linseed oil, and the liquid in which the lava floats will be a mixture of metholated spirits and a small amount of water. The water and the metholated spirits need to be balanced so that the densities of the linseed oil and the mixture are very very close. The oil needs to be poured into the bottle, and then the metholated spirits needs to be poured in slowly to prevent clouding. The water needs to be added in small amounts until the oil looks like it is about to float from the bottom.

Lava Lamp Number 2: The lava in this lamp is isopropryl alcohol, commonly known as rubbing alcohol, a household antiseptic. The liquid in which the lava will be suspended is mineral oil, which is found in almost pure state in bottles of baby oil. The alcohol needs to be poured in first, then followed by the baby oil, which must be poured in slowly to prevent clouding.

Lava Lamp Number 3: The lava in this lamp consists of parrafin (candle) wax, white petroleum jelly, and perchlorethylene, which is found in brake parts cleaning spray. To separate the perchlorethylene from other chemicals in the brake parts cleaner, the cleaner needs to be sprayed into a container of boiling water, and left to cool. The perchlorethylene will then sink to the bottom, and the water and other chemicals can be carefully poured off the top. The perchlorethylene, wax and petroleum jelly then need to be melted in a double boiler and mixed together. It must then be poured into the bottle and allowed to set. When the lava has set the bottle is filled with water.

Lava Lamp Number 4: The lava in this lamp is pure white petroleum jelly. To get the petroleum jelly into the bottle, put it in a ziplock sandwich bag, seal it, then cut one of the corners off and spray it down the middle of the bottle. Add a small amount of mineral turpentine to the petroleum jelly, as this makes it stay in large blobs when melted. The bottle is then slowly filled with metholated spirits. Small amounts of water are added to the metholated spirits, until the densities are balanced very closely. The densities need to be as close as possible to ensure proper operation. You can tell if the densities are balanced by heating up the lamp. If the lava does not rise, more water is needed. If the lava does not sink, more metholated spirits is needed.

Lava Lamp Number 5: This lamp uses mineral oil as the lava, with a mixture of metholated spirits and water as the surrounding liquid. The metholated spirits and water need to be balanced, the same way as in lamp number four.

*Each lamp is turned on three times, for a three hour period, to make sure that any lava activity in the lamps is not a one off occurance.

Results:

Lava Lamp Number 1: This lava lamp was an absolute failure. It did nothing whatsoever. Not to mention that the metholated spirits turned yellow and cloudy for some unknown reason.

Lava Lamp Number 2: This lava lamp was also a failure. It also did absolutely nothing.

Lava Lamp Number 3: This lava lamp did move. But then all of the lava floated to the top of the bottle and stayed there. It never came back down again, even when I took the lamp off the heat and allowed it to completely cool down. When the lava rose though, it did actually look like a real lava lamp. The lava flowed really well, and it had a fast warm up time. I think it needed more perchlorethylene to make the lava heavier. When I turned the lamp on for the second and third times, the lava became liquid, but still just stayed floating at the top of the bottle.

Lava Lamp Number 4: This lamp is a complete success!!! The lava flows really well, it rises and then comes back down again. It makes a lot of interesting shapes and is very beautiful and intriguing to watch. It takes about half an hour to 40 minutes to warm up properly. If you leave it on for more than two and a half hours though, it will overheat and stop moving all together. It really resembles a commerical lava lamp.

Lava Lamp Number 5: This lamp also did nothing. The metho went cloudy and it didn't move at all.

Conclusion

When two insoluble mixtures with very similar densities are heated, the heavier mixture will expand and float above the lighter mixture. As it cools, it will sink back down and once again become heavier than the lighter mixture. This is because as things are heated, they expand and become less dense, and as they cool, they contract and become more dense. This is clearly demonstrated by the way that a lava lamp works.

The most important thing when attempting to make a lava lamp is balancing the densities. They need to be so very close that it is really difficult to get the balance right. If the densities are not close enough, the lava will not rise or fall. The densities need to be so close so that when the lava expands, and it will only expand a very little, it will become lighter, or less dense, than the liquid which surrounds it. This is shown in the following diagram:

The actual ingredients of the lamp don't really matter that much, just as long as the densities are very close. It is possible to make a lava lamp with common ingredients that are found around the home, as shown in this experiment.

Discussion

This assignment has taught me a great deal about density, chemistry and science in general. It has been really frustrating at times, but in the end it turned out to be really rewarding and interesting. It has shown me that science really does have a huge impact on every aspect of our lives, even interior design!

When I read the information about how lava lamps work on the internet, I was surprised by the simplicity of the idea. The principals of density on which a lava lamp operates are simple enough for all science students to understand. It is amazing that something so simple in design could gain the following and popularity it has. After all, the lava lamp is not simply a scientific demonstration of density, or something that looks good in my bedroom, it is a cultural icon and the symbol of a generation.

I think that I could have improved my lava lamps if I were a more patient person. Some of the lamps may have possibly worked if I had the patience to spend days and days tinkering with them, and maybe even attempting the recipies again. I did spend a lot of time on the lamps that looked promising, such as lamps three and four, but the other lamps may have had potential also that I couldn't see. Balancing the densties took a lot of careful alterations and patience, and was very frustrating. Add one drop too much of one thing, and all the lava would float to the top. Add too much of the other and the lava would sink to the bottom and never move! I think that this infuriating problem would have even the most patient person feeling a little irritated!

I expected at the beginning of this experiment that it would be really easy, because all of the instructions I found on the internet made it seem that way. But I found that this experiment was a real challenge, and in the end, the only lamp that worked was one that I created myself, without using anybody else's recipe. Even though the lamps that did not work seemed like failures to me, I now realize that they helped me understand and figure out answers to problems, which in the end resulted in me creating my own successful lava lamp concoction.

I have really enjoyed doing this assingment, even though it was frustrating at times. I think this assingment was really worthwhile and interesting, as I not only learnt about science, I also ended up with something pretty for my dressing table! Everyone laughed when I said I was going to make lava lamps, but I have really enjoyed the challenge and it has opened my eyes to the many applications of science in our world.

 

Back to the Main Lava Lamp Page