Unit 6 Matter as Particles

Topic

Magic water glass trick

Curriculum Link

6.4 Air Pressure

Estimated Lesson Time

80 minutes

Introduction

Students will be able to explain daily life examples with the concept of air pressure in this activity. POE (Prediction-Observation-Explanation) strategy is used to help students construct their understanding of air pressure. Drawings are used to probe students' understanding of air pressure that is invisible. At first students are engaged to sense the existence of air pressure by ‘Magic water glass trick'. In task 1, teacher explains why it is difficult for liquid to enter the bottle by using the concept of air pressure. Drawings are used to help students to express their ideas regarding air pressure. In task 2, students are guided to explain why air pressure can exert force to stop liquid flowing out from a bottle. Finally, ask students to solve problems using the concept of air pressure.

Key Question

Does air really exist even we cannot see it?

Learning Objectives

In this activity, the students should be able to

  1. use drawings to express their understanding of air pressure (SP6);
  2. explain daily life examples using the concept of air pressure;
  3. predict the results by formulating hypothesis (SP3).

Teaching Plan

Task (Time) Brief Description Materials Objectives

Engagement
(15 min)

Students are engaged to sense the existence of air pressure by 'Magic water glass trick': Cover a glass of water with a piece of paper or glass; and then turn it over. Either teacher demonstrates this trick or asks students to do it.

Invite students to explain why the water can be kept in the glass in the aid of drawings.

  • Water glass, glass, plate/paper, white paper

 (1)

Exploration & Explanation
(20 min)

Task 1: Explain why does water stop flowing into an empty bottle?

  • POE strategy is used to help students construct their understanding of the concept of air pressure.
  • After Task 1, students should know: 'The bottle is filled up with air. It can exert a force to block the water flowing into the bottle.'
 (1) & (2)

Exploration & Explanation
(20 min)

Task 2: How could we strop water flowing out from a bottle?

  • Ask students to suggest methods to stop liquid flowing out from the bottle if we remove the tape from the bottom. (Note: Students are not provided with bottle cap until they request)
  • After the above exploration, teacher demonstrates how to stop the water to flow out from the bottle by closing its mouth with the cap.
  • Ask students to explain.
  • Worksheet 2
  • Plastic bottle with 1 hole at the bottom water
 (2) & (3)

Elaboration
(20 min)

Task 3: Blowing up balloon that is inside a plastic bottle.  

  • Use POE strategy to help students explain the experiences of Blowing up balloon that is inside a plastic bottle.

[Optional] Ask students to suggest methods to hold the inflated balloon.

 (2) & (3)

Apparatus and materials required: