A new, easy, simple, cheap lava lamp recipe.
Use mineral oil as the lava. Use 90% isopropyl alcohol (which most
drugstores can easily order) (our store had 91%, which
in theory should work just as well) 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." More of the 70% alcohol is needed than
the 90(1)%. So, plan ahead and leave enough room in your container for all the 70%
which you will be adding.
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. We used artists oil paints to add pigment to the mineral
oil and experienced some trouble when the paint gathered back together when heated.
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.
We recommend staying simple at first - just work with the 3 indgredients.
After you've mastered the motion, which is by far the hardest part, you may want to
throw in the additives. We know you want to add the food coloring right away but just hang on
because you'll have a hard time figuring out the balance if you have too many variables.