Science · Grade 2 · Movement and Simple Machines · Term 4

Speed and Direction

Students will explore how forces can change the speed and direction of moving objects.

• Ontario Curriculum Expectations
• 2-PS1-1

About This Topic

Simple Machines at Work explores the basic mechanical devices that make physical tasks easier. In the Ontario Grade 2 curriculum, students focus on six simple machines: the lever, inclined plane (ramp), pulley, wheel and axle, wedge, and screw. They learn how these machines can change the direction or amount of force needed to move an object. This unit emphasizes the practical application of science in solving everyday problems and the history of human ingenuity.

By identifying simple machines in their environment, students begin to see the world through an engineering lens. This topic is perfectly suited for station rotations and 'scavenger hunts.' When students can physically use a lever to lift a heavy book or a ramp to move a load, they understand the concept of 'mechanical advantage' without needing complex formulas. Active exploration makes these 'hidden' machines visible and understandable.

Key Questions

1. Compare the speed of a rolling ball on different surfaces.
2. Design an experiment to change the direction of a moving object.
3. Predict how adding more force will affect an object's speed.

Learning Objectives

• Compare the speed of an object rolling on different surfaces.
• Design an experiment to change the direction of a moving object.
• Predict how increasing the force applied to an object will affect its speed.
• Explain how forces cause changes in an object's speed and direction.

Before You Start

Push and Pull

Why: Students need to understand the basic concepts of pushing and pulling as forces before exploring how these forces change motion.

Objects in Motion

Why: Students should have a foundational understanding of objects moving before they investigate how speed and direction can be altered.

Key Vocabulary

Force	A push or a pull that can make an object move, stop, or change direction.
Speed	How fast an object is moving. It tells us the distance an object travels in a certain amount of time.
Direction	The path an object follows as it moves. It tells us where an object is going.
Surface	The outside layer or covering of an object, which can affect how other objects move across it.

Watch Out for These Misconceptions

Common Misconception

Simple machines 'create' energy or make work disappear.

What to Teach Instead

Students often think the machine does all the work. Use a ramp experiment to show that while it's 'easier' (less force), you have to move the object a longer distance. This helps them understand the trade-off involved in using machines.

Common Misconception

A machine must have a motor or batteries.

What to Teach Instead

Children often associate 'machine' with electronics. By exploring basic tools like scissors (levers/wedges) or a shovel, students learn that a machine is simply any tool that helps us use force more effectively.

Active Learning Ideas

Stations Rotation: Simple Machine Lab

Set up stations with a simple lever (ruler and eraser), a ramp, and a pulley. Students try to lift a heavy weight with and without the machine, recording which way felt 'easier' and why.

50 min·Small Groups

Gallery Walk: Machines in the Wild

Students walk around the school or playground in pairs to find examples of simple machines (e.g., a slide is a ramp, a seesaw is a lever). They take photos or draw what they find to share with the class.

30 min·Pairs

Think-Pair-Share: The Heavy Box Challenge

Students are given a scenario: 'How would you move a heavy box into a truck?' They think of a simple machine to help, pair up to discuss their choice, and share how that machine makes the work easier.

20 min·Pairs

Real-World Connections

• A hockey player uses their stick to apply force to a puck, changing its speed and direction to score a goal. Coaches analyze game footage to improve players' techniques for better control.
• Engineers designing playground equipment, like slides and swings, consider forces and surfaces to ensure safe and predictable movement for children.
• Delivery drivers use ramps to move heavy packages into trucks, understanding that the ramp's angle (an inclined plane) affects the force needed and the direction the package travels.

Assessment Ideas

Exit Ticket

Give students a toy car and a ramp. Ask them to record two ways they can change the car's speed and two ways they can change its direction. They should also write one sentence explaining which change required more force.

Quick Check

Present students with a scenario: 'A ball is rolling across a smooth floor. What will happen to its speed if it rolls onto a fuzzy carpet?' Ask students to write down their prediction and one reason why.

Discussion Prompt

Show a video clip of a game like soccer or basketball. Ask students: 'What forces are acting on the ball? How do players use these forces to change the ball's speed and direction?' Facilitate a class discussion, encouraging students to use the key vocabulary.

Frequently Asked Questions

What are the six simple machines?

The six simple machines are the lever, the inclined plane (ramp), the wheel and axle, the pulley, the wedge, and the screw. Each one helps us move things with less effort in a different way.

How did Indigenous people use simple machines?

Indigenous technologies have used simple machines for millennia. Examples include using levers to move heavy stones, wedges for splitting wood for longhouses, and inclined planes in the construction of various structures and tools.

How can active learning help students understand simple machines?

Active learning is vital because the benefit of a simple machine is something you 'feel.' When a student uses a lever to lift a stack of books that they couldn't lift with their bare hands, the concept of 'work made easier' becomes a physical reality rather than just a definition.

Where can we find simple machines in our classroom?

You can find them everywhere! A pencil sharpener uses a wheel and axle, a pair of scissors is a double lever with wedges, and even the screws holding your desk together are simple machines.