Stalactites and Stalagmites are those impressive pillars you see growing
in caves. If you aren't sure which is which, just remember that
stala'G'mites grow from the 'G'round. Now that you know how to tell a stalactite
from a stalagmite, find out how to grow your own.
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2 identical glasses
string or paper towel
2 paperclips or weights
bowl or pot
Fill the glass right to the top with water and dump it in the
bowl or pot. Do it again.
Start adding Epsom salts and stir to dissolve. Keep
adding Epsom salts and stirring until they won't
If you are using a pot, heat the pot on a stove. You
should be able to dissolve more Epsom salts in a hot
solution. Don't let the solution boil, but keep it on the
stove until it is very hot. Add more Epsom salts and keep
Divide the solution into the two glasses.
Find a location where they won't be disturbed for a few
days. There will be some dripping. If you are putting
them on a wood table, be sure to put a tray or something else
under the glasses to protect the table.
Cut a string. It needs to be long enough to cover the
distance between the glasses and hang down to the bottom of both
glass. Or use a rolled up paper towel to connect the two
Put the paperclip on each end of the string. Put one end
of the string in each of the glasses. There should be a
slight dip between the two glasses.
Watch as your stalagmite and stalactites grow over the next
I've read about this experiment many times over the years.
The directions always make it look simple. When it works, it
is easy. But there are lots of variables you can change if you
aren't getting results.
You need to dissolve a lot of Epsom salts in the water.
The stronger the solution, the faster you will see
results. If you need to grow something overnight, be sure
to heat the solution and slowly dissolve as much Epsom salts as
You can submerge the string in the solution first so that it
is all damp before putting it in the two glasses.
Check the string. If there is a dip below the height of
the water, there will be a lot of dripping. You can get a
pool between the two glasses. When the drips fall too
quickly, there's no time for the stalactite to form. Move
the glasses slightly apart to raise the height of the string
just a bit. It should slow down the dripping. Move
the glasses closer together if there is no dripping and the
string dries out.
Paper towel sucks up a lot of liquid and may be the fastest
way to grow your stalactite.
Your results will depend on the humidity in your home.
The results should be more dramatic in a home with a lower
If your string keeps drying out, you can use an eye dropper to
add one drop of the solution to each side of the string about
once an hour.
If you aren't allowed to heat the solution over the stove, ask
if you can boil some water. Put the hot water in the bowl
and add the Epsom salts directly to the hot water. You can
use hot water from the tap.
I've dissolved a lot of chemicals in water to make solutions
for growing crystals. It takes a LOT of Epsom salts to get
a super saturated solution.
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