BACKGROUND:
All "things" in the Universe can easily be
classified as either solids, liquids, gases, or plasma. A solid is a state
of matter with a boundary to its volume and shape. A liquid's shape and
volume is defined by the container it is in. A gas can take on the shape and
volume of the container that encloses it and can expand indefinitely. A
plasma refers to matter that is composed of electrically charged particles.
Plasma is very abundant in the Universe. The best way to illustrate these
states of matter is to use examples. A book is solid, water is a liquid, air
is composed of gases, and the "light" in a fluorescent lamp is
plasma.
A fifth state of matter has recently been confirmed.
This new state of matter is called the Bose-Einstein condensate. This state
of matter is only observed under extreme cold temperature. It seems that
under these temperatures the different elements and compounds act very
strange, some even seem to levitate! Scientists do not know all there is
about this state of matter, but it is a good example of how our
understanding of science changes with new information.
PROCEDURE:
- Go around the room and have students identify substances as being
solid, liquid, gas or plasma. Make a list on the board. A solid could be
a table or pencil; a liquid could be water or blood; gas could be air or
helium; and plasma could be a fluorescent bulb or the plasma ball. You
will not be able to find any examples of Bose-Einstein condensate.
- Tell your students that matter is made of elements. Some elements are
natural (90), others elements are man-made (19). Most substances that
your students are familiar with are made of these elements. The elements
can be solids, liquids, or gases. None of the natural elements are in a
state of plasma on Earth.
- Give students a Periodic Table Placemat and have them look at the
symbols. The Periodic Table is a "handy dandy" guide to all
the elements. Remember, the Periodic Table was developed to be looked at
as reference material, not something that was meant to be memorized.
Once you learn how to use the table, it can tell you many things about
the elements. You might want to point out the following elements that
the students may be familiar with:
H = hydrogen, a gas
He = helium, a gas
Ca = calcium, a solid
Si = silicon, a solid
Au = gold, a solid
U = uranium, a solid
Ag = silver, a solid
Hg = mercury, a liquid
- Students love to find elements on the Periodic Table. You can make a
racing game out of finding the elements by asking students to raise
their hands when they find a certain elements. They should have to be
able to tell you the element's atomic number when you call on them.
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