Soap Boat Experiment
Title: Soap Boat Experiment
Grade level: 5
Strand: Matter and Materials
Topic: Properties of and Changes in Matter
Specific Expectations: To describe changes observed in the properties of materials when the
materials interact with each other (eg., when water is combined with soap).
Materials Needed:
• Dish soap
• A heavier piece of paper (eg., cue card or light cardboard)
• Large bowl
• Spoon
• Water
Procedure:
• Fill a sink or any container with fresh, clean water.
• Cut out a shape of a boat using heavier paper or cardboard. Make your boat small,
approximately the size of a postage stamp. See boat template below.
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Once your boat is cut out, cut a small notch in the back of the boat (this acts as the
engine).
Float the boat in the container of water.
Using a small spoon, pour a drop or two of soap (the fuel) in the notch at the back of the
boat (the engine) and watch it zip across the water!
Scientific Explanation:
Water is made up of very tiny particles called molecules. These molecules are very close
together at the surface of the water, this attraction creates surface tension. When the soap touches
the surface of the water it destroys the surface tension. This creates space between the molecules
causing the molecules to quickly move away from each other. The water molecules under the
water’s surface then rise up filling the space, recreating the surface tension. This produces a
reaction, the forward movement of the boat across the water.
Cohesion - the force of attraction between two like molecules/materials
Surface tension - the attraction among water molecules at the surface of a liquid
References:
http://en.wikibooks.org/wiki/Wikijunior_Big_Book_of_Fun_Science_Experiments/Soap_powered_boat
http://www.suite101.com/article.cfm/homeschooling_science_fun/80311/2
Definitions:
http://hyperphysics.phy-astr.gsu.edu/hbase/surten.html#c1
The definition of “cohesion” has been taken from Jeff Scott’s class lecture notes
Presenters: Caitlin Dick and Stacy Jessop