Air Pressure Differentials - Collapsing Can - (Mark Rothenay)

Author

Mark Rothenay

Principle(s) Illustrated

• The purpose of this activity is for students to develop and revise a model on what is occurring inside the container in regards to pressure differentials. Not only does this event demonstrate pressure differentials but other physical principles can also be addressed such as change of matter and temperature.

Standards

1. Science & engineering standards

• Asking questions and defining problems

• Develop and use of models

• Engaging in arguments from evidence

2. Cross-cutting concept standards

• Cause and effect: Mechanism and explanation. Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.

• Systems and system models. Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.

• Develop a model that predicts and describes changes in particle motion, temperature and state of a pure substance when thermal energy is added or removed. (MS-PS1-4).

Questioning Script

Prior knowledge & experience:

Students will most likely be familiar with the states of matter such as when water is heated it will boil then form vapor. Students may also be familiar with an increase in temperature will increase the pressure.

Root question:

What do you believe will happen if the heated can is placed upside down in a cool layer of water?

Target response:

The warm water vapor will start to cool and condense on the inside of the can and thus will decrease the internal pressure due to the opening of the can being submerged and therefore blocked from any outside interference. This condensing inside the can will create a pressure differential in which the external atmospheric pressure will be greater when compared to inside the can and will eventually crush the can.

Common Misconceptions:

1. Magic.

2. Water will move inside the can and cause the can to crush.

3. The energy from the heating will weaken the can and cause it to collapse

Photographs and Movies

3. Disciplinary core idea standards