Date: Fri, 05 Mar 1999 14:32:49 -0800
From: George Fosselius <gfossel@ix.netcom.com>
To: Pinhole Listserv <pinhole@exploratorium.edu>
Subject: Re: Pinhole Digest #149 - Lava Lamps
> Question: lava lamps
> From: kathy saito <ksaito@foothill.net>
>
> Does anyone out there know how to make a lava lamp using household items?
George Fosselius:
I'm learning how to be a web-mentor so give me feedback if it helps or
hinders...(gfossel@ix.netcom.com --not the pinhole)
(I'm writing the URL's--addresses you can paste into your net browser Location window on
separate lines below to make it easy to copy)
I went to:
Altavista.com
and asked in the question box:
making lava lamps
out of the 3.5E06 (3 and a half million) hits...fortunately the fourth one was a
reference to this page:
http://www.students.uiuc.edu/~grim/lava_lamp.html
which I reproduce below with my comments as an absent minded chemist in * stars*
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31.3 How do I make a Lava Lamp?
Contributed by: Jim Webb <jnw4347@email.unc.edu>
Method #1. A new, easy, simple, cheap lava lamp recipe
Use mineral oil as the lava. Use 90% isopropyl alcohol (which most drugstores can
easily order) and 70% isopropyl alcohol (grocery-store rubbing alcohol) for the other
ingredient. In 90% alcohol the mineral oil will sink to the bottom; slowly add the
70% alcohol (gently mixing all the while; take your time) until the oil seems lighter
and is about to "jump" off the bottom. Use the two alcohols to adjust the
responsiveness of the "lava."
***all fairly non toxic substances***
This mixture is placed in a closed container (the "lava lamp shape" is not required,
although something fairly tall is good) and situated over a 40-watt bulb. If the "lava"
tends to collect at the top, try putting a dimmer on the bulb, or a fan at the top of the
container.
To dye the lava, use an oil-based dye like artists' oil paints or a chopped-up sharpie
marker. To dye the liquid around it, use food coloring.
Two suggestions for better performance: 1) Agitation will tend to make the mineral
oil form small bubbles unlike the large blobs we're all used to. The addition of a
hydrophobic solvent to the mixture will help the lava coalesce. Turpentine and other
paint solvents work well. To make sure what you use is hydrophobic, put some on
your hand (if it's so toxic you can't put it on your hand, do you want to put it in a
container that could break all over your room/desk/office?) and run a little water on
it. If the water beads, it should work fine. 2) For faster warm-up time, add some
antifreeze or (I've not tried it) liquid soap. Too much will cloud the alcohol. Keep in
mind that the addition of these chemicals may necessitate your readjusting the 90%
to 70% alcohol mixture.
***anitfreeze or auto coolant is muchly ethylene glycol a double alcohol mostly water
soluble and death to pets HO-CH2-CH2-OH***
Method #2. The official way. (from US Patent # 3,570,156 March 16, 1971)
The patent itself is not very specific as to proportions of ingredients. The solid
component (i.e., the waxy-looking stuff that bubbles) is said to consist of "a mineral
oil such as Ondina 17 (R.T.M.) with a light paraffin, carbon tetrachloride, a dye and
paraffin wax."
***methinks carbon tet is carcinogenic***
The medium this waxy stuff moves in is roughly 70/30% (by volume) water and a
liquid which will raise the coefficient of cubic thermal expansion, and generally make
the whole thing work better. The patent recommends propylene glycol for this;
however, glycerol, ethylene glycol, and polyethylene glycol (aka PEG) are also
mentioned as being sufficient.
This mixture is placed in a closed container (the "lava lamp shape" is not required,
although something fairly tall is good) and situated over a 40-watt bulb. If the "lava"
tends to collect at the top, try putting a dimmer on the bulb, or a fan at the top of the
container.
Method #3. The "less official" way (from Popular Electronics,[3] )How to make a Lava
Lamp, by Ralph Hubscher, _Popular Electronics_ magazine, March 1991, p. 31 (4).
Gernsback Publications.)
Several non-water-soluble chemicals fall under the category of being "just a little bit
heavier" than water, and are still viscous enough to form bubbles, not be terribly
poisonous, and have a great enough coefficient of expansion. Among them: Benzyl
alcohol (Specific Gravity 1.043 g/cm3), Cinnamyl Alcohol (SG 1.04), Diethyl
phthalate (SG 1.121) and Ethyl Salicylate (SG 1.13). [The specific gravity of distilled
water is 1.000.]
***methinks benzyl alcohol is carcinogenic***
Hubscher recommends using Benzyl Alcohol, which is used in the manufacture of
perfume and (in one of its forms) as a food additive. It can be obtained from
chemical or laboratory supply houses (check your yellow pages); the cheapest I could
find it for was $25 for 500 ml (probably 2, maybe 3 regular-sized lava lamps' worth).
An oil-soluble dye is nice to color the "lava"; Hubscher soaked the benzyl in a
chopped up red felt-tip pen and said it worked great. [Benzyl alcohol is "relatively
harmless", but don't drink it, and avoid touching & breathing it.]
Hubscher found that the benzyl and the water alone didn't do much, so he raised the
specific gravity of the water a little bit by adding table salt. A 4.8% salt solution (put
48 grams of salt in a container and fill it up to one liter with water) has a specific
gravity of about 1.032, closer to benzyl's 1.043. I find that the salt tends to cloud the
water a bit.. you might want to experiment with other additives. (Antifreeze?
Vinegar?)
This is put into a closed container and placed above a 40-watt bulb, as above. Either
way, I would suggest using distilled water and consider sterilizing the container by
immersing it in boiling water for a few minutes.. algae growing in lava lamps is not
very hip.
Caveat: Some of these chemicals are not good for you. ***agreed***
Caveat 2: Some of these companies are not good for you if they find you've been infringing
on their patent rights and trying to sell your new line of "magma lights."
Be careful.
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