Simple Machines Lesson Grade 4–5: Build and Test Machines

Grade Band: Upper Elementary (4–5)
Subject Area: Science

This free lesson introduces students to how everyday tools make work easier. Over several class periods, learners investigate simple machines by building working models, testing ideas, and explaining their thinking through diagrams and written instructions.

Overview

Students learn that many common tools are built on a small set of mechanical ideas. They begin by constructing moving models using interlocking bricks (such as LEGO or similar classroom building materials), then identify simple machines in real objects. Through testing and redesign, they discover how position, motion, and force affect performance. The lesson ends with students communicating how a machine works so another person can reproduce it.

Learning Goals

Students recognize and describe the six simple machines. They explain how a machine changes force or motion. They collect observations during experiments and use correct vocabulary such as force, load, friction, and fulcrum. Students also practice writing clear step-by-step directions that another student can successfully follow.

Materials

• Interlocking building bricks or classroom construction blocks (LEGO works well)
• String, cardboard, paper cups, and craft sticks
• Coins, washers, or small weights
• Boards or ramps
• Pictures or magazines showing tools
• Chart paper or whiteboard
• Student notebooks

Preparation

Before the lesson, gather building materials into small group kits. Prepare several demonstration stations showing different types of machines. Create a vocabulary chart with space to add examples during the unit. Test materials to ensure student models can lift or move an object.

Teaching Procedure

Session 1

1. Ask students to list tools they have used recently. Guide discussion toward the idea that tools help people do work more easily.
2. Students work in pairs to freely build a moving model using the construction bricks. Encourage experimentation rather than giving instructions.
3. Each pair demonstrates its model. Students sketch their design and label moving parts in their notebooks.

Session 2

1. Introduce the six simple machines: lever, wheel and axle, pulley, inclined plane, wedge, and screw. Add definitions to a class chart.
2. Students rotate through demonstration stations and record what each machine does and where it might be used.
3. As a class, sort pictures of real objects into machine categories and discuss reasoning.

Session 3

1. Demonstrate a lever using a ruler and block. Students predict how moving the fulcrum will affect lifting.
2. Groups test different fulcrum positions while lifting weights and record observations.
3. Students share findings and connect results to the idea that machines change effort and distance.

Session 4

1. Students modify or rebuild their original model so it clearly represents one type of simple machine.
2. Groups prepare a short explanation describing the load, the applied force, and the moving parts.
3. Groups present their working model while classmates ask questions about how it functions.

Session 5

1. Model how to write precise numbered instructions using clear vocabulary.
2. Students build a small object using a few blocks and write directions so another student can recreate it.
3. Partners follow the directions and provide feedback. Students revise their instructions for clarity.

Assessment

• Participation in investigations
• Correct identification of simple machines
• Recorded observations from the lever experiment
• Clarity of written instructions
• Explanation during group presentation

Differentiation

Provide labeled diagrams and sentence starters for students who need writing support. Allow oral explanations instead of written responses when necessary. Challenge advanced students to combine two simple machines in one design or improve lifting efficiency.

Extension Ideas

Students can search the school building for real examples of simple machines and photograph them. Another option is to design a device that solves a classroom problem, such as moving books or opening a container. Students may also create a digital slideshow explaining how one machine works in daily life.

Simple Machines Quick Reference

Students often need quick reminders after the activity. This reference helps them connect classroom models to real-world tools they already know.

Lever

A rigid bar that pivots on a fixed point (fulcrum) to move a load.

Common examples students can look for: seesaw, crowbar, claw hammer pulling a nail, bottle opener, stapler.

Inclined Plane

A slanted surface that reduces the effort needed to lift an object.

Common examples students can look for: ramp, slide, driveway, wheelchair ramp, loading ramp for trucks.

Wheel and Axle

A large wheel connected to a smaller rotating shaft that multiplies force or motion.

Common examples students can look for: doorknob, rolling office chair, bicycle wheel, pizza cutter, steering wheel.

Pulley

A grooved wheel with a rope or string that changes the direction of force.

Common examples students can look for: flagpole rope, window blinds cord, well bucket, construction cranes.

Wedge

A moving inclined plane that splits or cuts materials apart.

Common examples students can look for: knife, axe, doorstop, chisel, nail.

Screw

An inclined plane wrapped around a cylinder that holds objects together or lifts materials.

Common examples students can look for: jar lid, wood screw, light bulb base, vise clamp.

Try This Challenge

Ask students to find one example of each simple machine at home or school and sketch it in their notebook. Encourage them to explain how it makes work easier.