Biology/Chemistry
Surface
Tension (Soap Boat)
|
John J. Scavo |
Richards
Career Academy |
|
5009 S. Laflin |
|
|
Chicago IL 60609 |
|
|
(773) 535-4945 |
Objective(s):
This
activity is written for students of all ages.
Students will become familiar with surface tension.
Students will determine if soap will affect
surface tension. Students will
determine if water temperature affects surface tension.
Materials:
Index
card, any size
clean
water
Scissors
clean 9 pie tin or other container
Liquid
soap
Strategy:
Fill
the pie tin half full of water and have it sitting on the front table
when the
students come in.
Cut
a triangle out of the index card (2 high and 1 wide should do it.) Hold it up to the students and tell them
that it is a boat.
Cut
a smaller triangle out of the bottom of the boat. Tell
the students that this is where the motor goes.
Place
your boat in the water near the edge of the pie tin.
It will not go anywhere.
Next, remove the boat from the water.
Place
a drop of the liquid detergent on you finger and touch it just inside
the V
notch of the boat. Gently place the
boat back in the pan of water, soapy side down, and it will jet across
the
surface much to the delight and amazement of all involved.
Have
the students try the process themselves.
They should have a fun time.
Students
could try different types of soaps, and both warm and cold water. Students could try different boat styles to
see which kind goes fastest.
Performance
Assessment:
Students
will demonstrate the ability to work scientifically and accurately in
the lab.
Students
will make a hypothesis as to why and how the different conditions in
the water
affected the surface tension.
Students
should analyze error in the technique that may have affected the
results.
Students
will observe the reaction when soap breaks the hydrogen bonds of the
water.
Students
will notice a skin on the surface of the water, or surface tension.
Conclusions:
-
Students will have explored the possibilities of surface tension. They will see how detergent and heat lower
surface tension. Higher level students
may explore bonds and polarity affecting surface tension.
References:
Zero
to Einstein in 60 seconds,
The Wild Goose Company, pp. 14-16.
http://nerdscience.homepage.com/soapboats.htm