Teacher Demo: Air Pressure

This demo illustrates the presence of atmospheric air pressure and shows how the force that it exerts is greater than the force of gravity in some situations.


Wear appropriate PPE: safety goggles.

  1. Fill the glass with water right up to the brim.
  2. Place the index card on top of glass and hold it firmly in place.
  3. Predict

Students engage in Think, Pair, Share (see Teaching Suggestions/Hints):

  • Think: What will happen when the glass is held upside down and the index card is no longer held in place?
  • Pair: Discuss the question with a partner.
  • Share: Hold a brief class discussion on the prediction.
  1. Explain

Ask students to justify their predictions using their existing knowledge.

  1. Observe

Lift the water-filled glass over the tray with one hand, holding the index card to the mouth of the glass with the other hand. Carefully turn the glass upside down. Release the card.

  1. Explain

Ask students to explain their observations.

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Significant Figures in Measurements

Mr. Key outlines how we use numbers in science, with specific regards to precision and significance.

Please note that all questions, comments and critiques are welcome. However, because the primary purpose of these videos is educational for students/educators, the comments are moderated. Any comments that are deemed abusive, inappropriate, or unrelated to the topic matter will not be posted and the user potentially blocked.


Ontario Association of Physics Teachers Conference 2017 May 11-13

Don’t miss this year’s conference at the Lassonde School of Engineering at York University. This year we are going beyond the cognitive domain and highlighting Affective Physics: Harnessing Emotion to Improve Learning. Come and see how you can alter your classrooms and lessons to improve student motivation, focus and confidence.

We have a full slate of workshops to choose from. Stretch your mind learning about Gravitational Waves and Quantum Computing. Find physics applications in Forensic Blood Analysis and House Construction. Discover useful technology with Apps for Astronomy and Video Conferencing. Strengthen your pedagogy with Cooperative Groups and Knowledge Building. Have fun with Physics Games and Crazy Demos.

The last day for early bird registration discount is Monday April 11, so don’t delay!

For more information and registration go to:            https://oaopt.wildapricot.org/Conference-2017

Do Glasses Ruin Your Eyesight?

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