BACKGROUND:
Water is so common to students that
they can't see its special properties, but water (without any additives)
has characteristics that make it unique. It has a high boiling point,
low freezing point, is tasteless, and odorless.
The density of a substance is the mass of
that substance compared to the volume that the substance occupies.
Density will vary depending upon the temperature. The density of
water as a liquid is higher than that of water vapor. Other substances
have other densities, in this lab we want the students to compare the different
densities of certain liquids while comparing them to water. After
the students complete the density portion of the lab, they can start thinking
about the effects of oil pollution on water. Oil will float and cause
a problem for organisms that live on the surface.
PROCEDURE:
- This activity looks at the
different densities of different liquids and how this information can be
useful knowledge when cleaning an oil spill. Water is so common to
students that they can't see its special properties, but water (without
any additives) has characteristics that make it unique. It has a
high boiling point, low freezing point, is tasteless, and odorless.
- Write the chemical formula of water
on the board and explain the components that make up water, namely, hydrogen
and oxygen. Ask the students what the natural states of matter hydrogen
and oxygen are usually found as (Gas). Make sure they know and understand
the role of water in the water cycle.
- The students should have a tub of
water and they should pour oil on it representing an oil spill. Give
them 3 substances: soap in a small vial, craft sticks, and an adsorptive
substance like cotton swabs or crepe paper. Have the students design
a way to capture the oil and clean up the spill.
- Hopefully they learned that because
oil is less dense than water it will float on the water. The oil
can actually be "scraped" from the surface of the water and cleaned in
that manner.
- Discuss the effects of contamination
and oil pollution on the environment, wildlife, and humans. After
your discussion talk about some possible clean-up methods and how these
methods might be useful.
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