Science · Year 5 · Forces in Action · Summer Term

Air Resistance

Investigating how air resistance opposes motion and how shape affects its impact.

• National Curriculum Attainment Targets
• NC-KS2-Science-Y5-Forces-1

About This Topic

Air resistance, also known as drag, is a force that opposes the motion of an object through the air. It is caused by the friction between the object's surface and the air molecules it encounters. Understanding air resistance helps explain why objects of different shapes fall at different rates, even if they have the same mass. For example, a flat sheet of paper falls much slower than a crumpled ball of the same paper because the flat sheet experiences greater air resistance.

Year 5 students will explore how the shape and surface area of an object significantly influence the amount of air resistance it experiences. Streamlined shapes, like those found on race cars or airplanes, are designed to minimize drag, allowing them to move more efficiently through the air. Conversely, objects with large, flat surfaces experience more drag. This concept is crucial for understanding motion and forces in everyday life, from cycling to skydiving.

Investigating air resistance benefits greatly from hands-on exploration. Building and testing different parachute designs or comparing the fall times of various shapes allows students to directly observe and measure the effects of drag, making the abstract concept of force tangible and memorable.

Key Questions

1. Explain how air resistance affects falling objects.
2. Analyze how the shape of a vehicle affects its speed through air.
3. Design an experiment to compare the air resistance of different shapes.

Watch Out for These Misconceptions

Common Misconception

Heavier objects always fall faster than lighter objects.

What to Teach Instead

This misconception often overlooks air resistance. Hands-on experiments with objects of similar size but different weights, or objects of similar weights but different shapes, clearly demonstrate that air resistance plays a significant role in fall speed. Observing a feather and a stone fall in a vacuum versus in air highlights this difference.

Common Misconception

Air is empty space and offers no resistance.

What to Teach Instead

Students may believe air is negligible. Demonstrations like feeling the wind or seeing how a parachute slows a falling object show that air is a substance that can exert force. Comparing the fall of a crumpled paper ball versus a flat sheet directly illustrates air's resistance.

Active Learning Ideas

Parachute Design Challenge

Students design and build parachutes using different materials and sizes. They then test their parachutes by dropping them from a set height, measuring the time it takes to reach the ground and observing how air resistance affects their descent.

60 min·Small Groups

Shape Drop Investigation

Provide students with identical masses attached to different shapes (e.g., flat, spherical, pointed). Students predict which will fall fastest and then conduct timed drops to compare their results, analyzing how shape influences air resistance.

45 min·Small Groups

Streamlining Simulation

Using a fan and lightweight objects, students observe how different shapes interact with moving air. They can experiment with placing objects in the airflow to see which shapes are most easily pushed or slowed down.

30 min·Individual

Frequently Asked Questions

How does the shape of an object affect air resistance?

Objects with larger surface areas facing the direction of motion generally experience more air resistance. Streamlined shapes, which are smooth and tapered, allow air to flow around them more easily, reducing drag. Flat or irregular shapes create more turbulence and push against the air more forcefully.

What is the difference between air resistance and gravity?

Gravity is the force that pulls objects towards the center of the Earth, causing them to fall. Air resistance is a force that opposes motion through the air. It acts in the opposite direction to the object's movement. Both forces are acting on a falling object.

Why do skydivers spread out their bodies?

Skydivers spread out their bodies to increase their surface area. This increases the air resistance acting on them, slowing down their descent. By changing their body position, they can control how quickly they fall.

How can active learning help students understand air resistance?

Active learning, through designing parachutes or comparing the fall of different shapes, allows students to directly experience and measure air resistance. These hands-on investigations transform abstract concepts into observable phenomena, fostering deeper understanding and retention than passive learning alone.

From the Blog

Collaborative Problem Solving in the Classroom: A Teacher's Guide

A research-backed guide to implementing collaborative problem solving in K-12 classrooms, with step-by-step strategies, grade adaptations, and pitfalls to avoid.