Science · Year 2 · Forces in Motion · Term 2

Friction on Different Surfaces

Students will experiment with moving objects across various surfaces to observe the effects of friction.

• ACARA Content Descriptions
• AC9S2U03

About This Topic

Simple machines are tools that make work easier by changing the way forces are applied. In this topic, Year 2 students explore basic machines like ramps (inclined planes), wheels and axles, and levers. They discover that by using these tools, they can move heavier loads with less effort. This connects to the 'Science as a Human Endeavour' strand by showing how humans design tools to solve problems.

In Australia, simple machines have been used for millennia, from the use of a woomera (spear thrower) to the modern ramps used for accessibility in our schools. This topic comes alive when students can physically test different tools and model how they reduce the 'push' or 'pull' needed to get a job done.

Key Questions

1. Compare the amount of friction on a smooth floor versus a carpeted floor.
2. Explain how friction helps us walk without slipping.
3. Predict which surface will make a toy car stop fastest.

Learning Objectives

• Compare the amount of friction acting on an object moving across a smooth surface versus a rough surface.
• Explain the role of friction in preventing slipping when walking.
• Predict which surface will cause a toy car to stop in the shortest distance due to friction.
• Identify surfaces that create more friction than others.

Before You Start

Push and Pull Forces

Why: Students need to understand the basic concepts of pushing and pulling to investigate how friction affects motion.

Objects in Motion

Why: Students should have prior experience observing and describing how objects move to compare the effects of different surfaces on that motion.

Key Vocabulary

Friction	A force that opposes motion when two surfaces rub against each other. It can slow things down.
Surface	The outside part or uppermost layer of something. Different surfaces feel different, like smooth or rough.
Motion	The act or process of moving or being moved. Friction affects how things move.
Rough surface	A surface with an uneven texture that creates more friction, like carpet or sandpaper.
Smooth surface	A surface with an even texture that creates less friction, like a polished floor or ice.

Watch Out for These Misconceptions

Common Misconception

Students often think that simple machines 'create' energy or make the work disappear.

What to Teach Instead

Explain that we still do the work, but the machine spreads it out. Using a long ramp versus a short one helps them see that while it's 'easier' (less force), they have to push the object a longer distance.

Common Misconception

Children may not recognise everyday objects like a door handle or a slide as 'machines'.

What to Teach Instead

A 'Gallery Walk' of schoolyard objects can help. Labeling a slide as a 'ramp' and a door handle as a 'wheel' helps them see the science in their daily environment.

Active Learning Ideas

Inquiry Circle: The Ramp Challenge

Groups try to lift a heavy tub of blocks onto a table. Then, they use a long plank as a ramp. They discuss which way felt 'easier' and experiment with making the ramp longer or steeper.

45 min·Small Groups

Stations Rotation: Machine Hunt

Set up stations with a wheelbarrow, a pair of scissors (lever), a toy car (wheel and axle), and a screw. Students identify where the 'push' or 'pull' goes and how the machine helps.

40 min·Small Groups

Think-Pair-Share: The Woomera Wonder

Show a video of a woomera being used. Students think about how this 'extra arm' acts as a lever to make the spear go further, then discuss with a partner how it makes the hunter's job easier.

20 min·Pairs

Real-World Connections

• Shoe designers create different tread patterns on the soles of sneakers and boots to increase friction. This helps athletes run faster on sports fields and hikers grip slippery trails.
• Car mechanics examine tire treads to ensure they provide enough friction with the road. Good tire friction is essential for safe braking and steering, especially in wet conditions.
• Playground designers choose materials for slides and climbing structures. Smooth surfaces on slides allow for faster movement, while rougher surfaces on climbing walls offer better grip.

Assessment Ideas

Exit Ticket

Give students a small toy car and a card with two surfaces drawn on it (e.g., a smooth line and a bumpy line). Ask them to predict which surface will stop the car fastest and write one sentence explaining why, using the word 'friction'.

Discussion Prompt

Ask students: 'Imagine you are wearing smooth-soled shoes and walking on a wet, tiled floor. What might happen? Now, imagine you are wearing shoes with deep treads. How does that change what might happen?' Guide them to use the term 'friction' in their answers.

Quick Check

Set up three different surfaces (e.g., a piece of wood, a carpet square, a laminated sheet). Have students place a block on each surface and give it a gentle push. Ask them to point to the surface where the block stopped fastest and then slowest, and explain their choice using the concept of friction.

Frequently Asked Questions

Which simple machines are most important for Year 2?

Focus on the ones they see every day: the ramp (inclined plane), the wheel and axle, and the lever. These are the easiest to demonstrate with classroom objects and playground equipment.

How does a woomera work as a simple machine?

A woomera acts as a lever. It effectively extends the length of the thrower's arm, allowing them to apply force over a greater distance and launch a spear with much more speed and power than by hand alone.

How can active learning help students understand simple machines?

Simple machines are all about 'mechanical advantage,' which is a fancy way of saying 'it feels easier.' Active learning lets students *feel* that difference. When they use a lever to lift a heavy book, the 'aha!' moment comes from the physical sensation of decreased effort.

What is a good 'design challenge' for this topic?

Ask students to move a 'heavy' rock (a large stone) across the classroom without lifting it. They can use dowels as rollers (wheels) or a plank as a lever. This encourages collaborative problem-solving and engineering thinking.