Glitter Globe
Materials:
- Rubbing (isopropyl) alcohol
- Vegetable oil
- A clear plastic or glass container with an interesting shape (long, skinny
olive jars and the fancy jars that hold some marmalades, jams, or jellies
work well)
- Small beads, sequins, glitter, or other tiny, shiny things
- Food coloring (if you want)
- Clear tape (if you want)
1) Fill about 1/4 of the jar with rubbing alcohol. Add a drop of food coloring.
Don't forget to be careful with glass.
2) Pour vegetable oil into the jar. Leave about 1/2 an inch of air at the top of
the jar. Let the globs of oil settle. Is the oil on top of the alcohol or
underneath it?
3) Drop tiny, shiny things into the jar. Use as many as you want. Don't use
anything too heavy-like a marble-that might break the jar when you shake it.
4) When all the tiny things are in the jar, carefully pour in more oil until the jar
is completely full-right up to the rim.
5) Screw the lid of the jar on very tightly. (If you want, you can tape around the
lid to make sure it won't leak.)
6) Gently shake the jar. The oil and alcohol will mix and turn a milky color,
and the beads and glitter will float and spin.
7) Let the oil settle again. That will take about 5 or 10 minutes. Now spin the
jar instead of shaking it. What happens?
Why doesn't the oil float on top of the alcohol?
Since oil floats on top of water, you might have thought that oil would float on
top of alcohol, too. But the oil sinks to the bottom and the alcohol floats on
top of the oil. Even though water and alcohol are both clear liquids, they have
different densities. Alcohol floats on top of oil because a drop of alcohol is
lighter than a drop of oil the same size.
Why don't oil and alcohol mix? For that matter, why don't oil and water mix?
The answers to these questions have to do with the molecules that make up
oil, water, and alcohol. Molecules are made up of atoms, and atoms are
made up of positively charged protons, negatively charged electrons, and
uncharged neutrons.
The atoms that make up water molecules and alcohol molecules are
arranged so that there is more positive charge in one part of the molecule
and more negative charge in another part of the molecule. Molecules like
this are called polar molecules.
The charged particles in an oil molecule are distributed more or less evenly
throughout the molecule. Molecules like this are called nonpolar molecules.
Polar molecules like to stick together. That's because positive charges
attract negative charges. So the positive part of a polar molecule attracts the
negative part of another polar molecule, and the two molecules tend to stay
together. When you try to mix water and oil or alcohol and oil, the polar
molecules stick together, keeping the oil molecules from getting between
them-and the two don't mix. When you try to mix water and alcohol, they mix
fine, since both are made of polar molecules.
What's this pretty toy doing in a set of science experiments? It seems more
like an art project to me.
When you make a Glitter Globe, you're experimenting with two liquids that
won't mix with each other--alcohol and oil. Playing with the Glitter Globe
gives you a chance to watch how liquids flow. And in the process, you make
something that's pretty.
Some people think that science and art have very little in common. At the
Exploratorium, we disagree. Both artists and scientists start their work by
noticing something interesting or unusual in the world around them. Both
artists and scientists experiment with the things they have noticed. Art and
science begin in the same place-with noticing and experimenting.
Credits: http://www.exploratorium.edu
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