Flask Fountain Inquiry
flask, capped with a rubber stopper and glass tube and partially
filled with water, is heated and then inverted into a beaker
of waterthe water in the beaker rushes up and into the
flask. Students propose theories and gather data to investigate
them. A few classroom students will share responses during
the QuickTime movie demonstration.
Leading the Activity
Inquiry Teaching Strategies
Teacher Background Information
As the water and air in the flask are heated they expand. The air in the flask expands and can no longer be contained in the flask and some is pushed out the mouth of the glass tubethis cannot be easily observed. As the water heats, some of the liquid turns to a gas and begins to fill the flask above the liquid. As more and more liquid turns to gas, we can easily observe the steam escaping out the mouth of the tube. When the flask fountain is inverted into the beaker of water, the water (liquid and gas) continues to expand. We can observe the liquid (now in the neck of the flask) being pushed out of the flask. This is a "step" in the observations that may be overlooked by students. When the flask fountain is removed from the heat it cools and the contents contract. This contraction creates less pressure within the flask compared with the air outside the flask (a partial vacuum). The greater air pressure outside the flask forces the liquid back into the flask. If there is a dramatic difference in the pressure inside and outside the flask, then the water will rush into the flask as it cools. If the flask cools slowly, or if the difference in pressure is not great, the water will rise in the flask more slow
Range of Results
It is likely that students will respond with many theories about the problem without suggesting ways of generating data to support their ideas. Whenever possible, allow time and opportunity for students to realize for themselves that additional data is needed and that they must determine how to generate that data. As students have additional practice with inquiry problems, they may begin to propose data generating activities more readily. It is possible that students will be uncomfortable with inquiry problems. They may ask you to solve the problem for them, or validate their ideas and data. Resist the temptation to provide "free data" or otherwise prompt the students. Remind the class that it is up to them to decide what new data is needed, how to obtain that data, what data to trust, if their ideas are correct, and when they are satisfied that they have solved the problem.
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Notes on the Inquiry Teaching Strategy
For further discussion of inquiry, student discovery, and constructivism, here are some general notes:
Accept all data answers.
Encourage data generating responses.
Observe students for evidence of inquiry skills.
Observing students while they work on inquiry problems can provide the
teacher with valuable information about their students. Watch for student
language and behaviors which indicate growth in inquiry skills.
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