Science · Grade 2 · Air and Water in the Environment · Term 3

Air Pressure and Movement

Students will explore how air pressure can create movement and lift objects.

• Ontario Curriculum Expectations
• 2-PS1-1

About This Topic

The Water Cycle introduces students to the continuous movement of water on, above, and below the surface of the Earth. In the Ontario Grade 2 curriculum, students learn about the processes of evaporation, condensation, and precipitation. They explore how water changes state as it moves through the cycle and why this process is vital for life on Earth. This unit also emphasizes the importance of clean water and our responsibility to protect this precious resource.

By tracing the journey of a water droplet, students begin to see the Earth as a connected system. This topic is highly effective when students can model the cycle themselves. Whether creating a 'cloud in a jar' or simulating rainfall, active learning allows students to see the transitions between states of matter in a controlled way. These interactive experiences help students visualize a global process on a scale they can understand.

Key Questions

1. Analyze how air pressure helps an airplane fly.
2. Design a simple device that uses air to move an object.
3. Predict how changing the amount of air in a balloon affects its movement.

Learning Objectives

• Design a simple device that uses air to move an object.
• Predict how changing the amount of air in a balloon affects its movement.
• Explain how air pressure can create movement and lift objects.
• Analyze how air pressure helps an airplane fly.

Before You Start

Properties of Objects and Materials

Why: Students need to understand that air is a substance with properties, including weight and the ability to exert force, before exploring air pressure.

Forces Acting on Objects

Why: A basic understanding of pushes and pulls is necessary to comprehend how air pressure can cause movement and lift.

Key Vocabulary

Air Pressure	The force exerted by air molecules pushing on a surface. This force is present all around us, even though we cannot see it.
Movement	The act or process of changing position or place. In this topic, air pressure causes objects or air itself to move.
Lift	An upward force that opposes gravity, often created by the movement of air. Airplanes use lift to fly.
Force	A push or pull on an object that can cause it to move, stop, or change direction. Air pressure exerts a force.

Watch Out for These Misconceptions

Common Misconception

Clouds are made of smoke or cotton-like solid material.

What to Teach Instead

Students often think clouds are solid objects. Using a 'cloud in a jar' simulation helps them see that clouds are actually made of tiny water droplets or ice crystals that have condensed from invisible gas.

Common Misconception

Water only evaporates when it is boiling.

What to Teach Instead

Children often associate evaporation with a boiling kettle. By leaving a shallow dish of water out over several days and measuring the level, students can see that evaporation happens at room temperature too.

Active Learning Ideas

Simulation Game: Cloud in a Jar

In small groups, students watch as warm water and ice are used to create a 'cloud' inside a glass jar. They observe the mist forming and discuss how this represents condensation in the real sky.

30 min·Small Groups

Role Play: The Journey of a Drop

Students are assigned roles like 'The Sun,' 'The Puddle,' 'The Cloud,' and 'The Rain.' They act out the water cycle, moving from one station to the next as they change states from liquid to gas and back again.

40 min·Whole Class

Think-Pair-Share: Where Did the Puddle Go?

After a rainstorm, students observe a puddle on the pavement. The next day, it's gone. They think about where the water went, pair up to discuss the process of evaporation, and share their ideas with the class.

15 min·Pairs

Real-World Connections

• Aero-engineers design aircraft like commercial airplanes and helicopters. They use their understanding of air pressure and airflow to create wings and rotors that generate lift, allowing these vehicles to fly safely and efficiently.
• Sailors and windsurfers harness the power of moving air, or wind, to propel their boats and boards across the water. They adjust sails to capture the wind's force, demonstrating how air pressure differences create movement.

Assessment Ideas

Exit Ticket

Give students a small drawing of a balloon. Ask them to draw arrows showing which way the balloon will move if they blow more air into it, and to write one sentence explaining why it moves that way.

Quick Check

Hold up a piece of paper. Ask students to predict what will happen if you blow hard just above the top surface of the paper. Then, perform the action and ask students to explain the result using the term 'air pressure'.

Discussion Prompt

Pose the question: 'How does a kite stay up in the air?' Guide students to discuss the role of wind and the shape of the kite in creating lift, relating it to air pressure differences.

Frequently Asked Questions

How can I include Indigenous perspectives on water?

Incorporate the concept of 'Water Walkers' and the work of Anishinaabe grandmothers who walk to protect the Great Lakes. This teaches students that water is a living entity that deserves respect and protection, a key part of many Indigenous worldviews.

What is the best way to explain evaporation to 7-year-olds?

Describe it as water 'turning into an invisible ghost' and floating up into the sky. When it gets cold high up, those 'ghosts' bunch together to become visible again as clouds. This helps them visualize the change from liquid to gas.

How can active learning help students understand the water cycle?

Active learning, like the 'Journey of a Drop' role play, turns a complex, multi-step process into a physical experience. When students 'become' the water, they internalize the sequence of events and the conditions (like heat or cold) required for each change, making the cycle easier to remember.

Why is the water cycle important for Ontario farmers?

Farmers rely on the water cycle to bring rain to their crops. Understanding the cycle helps students see the connection between the weather, our food supply, and the importance of having a steady cycle of rain and sun.