Embedded Files
Introduction
Introduction
In this learning sequence we explore one of our simple machines – the lever.
Watch the short video that gives you an overview of today’s lesson.
Inquiry question and intentions
Inquiry question and intentions
Inquiry question:
How do levers make work easier?
Learning intentions:
To explain how levers make work easier.
To understand the different classes of levers.
To measure forces acting on levers.
To understand how levers provide mechanical advantage.
To use a simulation model to explore how levers balance.
Background information
Background information
A lever is a simple machine made of a rigid beam and a fulcrum. It is used to lift or move objects.
The effort (input force) and load (output force) are applied to either end of the beam.
The fulcrum is the point on which the beam pivots.
When an effort is applied to one end of the lever, a load is applied at the other end of the lever. This will move a mass upward.
Levers rely on torque for their operation. Levers can either magnify a force or magnify the distance moved by a force. This is called leverage.
Activity 1: Definitions
Activity 1: Definitions
The diagram in the background information shows one class of lever that can be used. Each lever system has all the components shown in that diagram but their order in the system can differ. For the investigation in Activity 2, you will be exploring the lever system shown in the diagram.
Task 1 - Classes of levers
Task 1 - Classes of levers
Answer the following questions in your exercise book or folder:
What are the different classes of levers?
What class do you think the diagram in the background information is? Why?
Task 2 - Find the meaning
Task 2 - Find the meaning
Research the meanings of the following terms and write the definitions in your exercise book or folder:
pivot
magnify
torque
leverage.
Activity 2: Investigating levers
Activity 2: Investigating levers
Complete practical investigation on the impact of the position of the fulcrum on a lever.
Note: The materials used in this experiment are suggested only. If you have other items that you could use instead, make the modifications to your experiment.
Complete all your work in the Investigation report document.
Click on the button to open a new tab and view the Google Doc activity sheet.
Click on the Use Template button to create a copy for you to edit.
Activity 3: Archimedes and levers
Activity 3: Archimedes and levers
Task 1 - The ideas of Archimedes
Task 1 - The ideas of Archimedes
Watch the video The mighty mathematics of the lever.
Answer the following questions in your exercise book or folder:
What important relationship did Archimedes discover when working with levers?
Draw a labelled diagram to show what he found.
Define work, using the words force and distance.
“Give me a lever long enough and a fulcrum on which to place it, and I shall move the world”. - Archimedes
What do you think he meant by this statement and how does it relate to the use of levers?
The mighty mathematics of the lever
Duration 4:45
Task 2 - Conservation of mechanical energy
Task 2 - Conservation of mechanical energy
Balancing a lever is an example of the conservation of mechanical energy in a system.
Work in equals work out, where work is defined as force times distance.
Work is measured in Joules (J).
Force (F) is measured in Newtons (N).
Distance (d) is measured in metres (m).
The resistance arm’s “moment of force” is equal to the effort arm’s “moment of force”.
Activity 4: Classes of levers
Activity 4: Classes of levers
In Activity 1, you discovered that there are three classes of levers.
First class levers – the fulcrum is in the middle of the effort and the load.
Second class levers – the load is in the middle between the fulcrum and the effort.
Third class levers – the effort is in the middle between the fulcrum and the load.
In our investigation we explored a first class lever, where the fulcrum was in between the load and the force.
Task 1
Task 1
Watch the video, Difference between 1st, 2nd, and 3rd class levers, to consolidate your understanding.
Use the Class of levers actvity Google Doc to demonstrate your understanding.
Click on the button to open a new tab and view the Google Doc activity sheet.
Click on the Use Template button to create a copy for you to edit.
Difference between 1st, 2nd, and 3rd class levers
Duration 1:51
Task 2 - Applying your understanding of classes of levers to every day objects
Task 2 - Applying your understanding of classes of levers to every day objects
Extension - Further explorations
Extension - Further explorations
Task 1 - Levers in the body
Task 1 - Levers in the body
Visit the What levers does your body use? page on the Science Learning Hub website to investigate the levers in the human body.
Next, explore Movement analysis in sport on the BBC Bitesize website.
Where in your body would your find an example of each class of lever?
Task 2 - Design challenge
Task 2 - Design challenge
Using your knowledge of levers, design and build a full robotic arm that can lift a cup off a table.
You could use cardboard, string, straws, paddle-pop sticks, tape, split-pins, building blocks, paperclips and rubber bands.
Start by measuring the lengths of your upper and lower arm and think about where muscles are attached.
Handing in your work
Handing in your work
Don't forget to hand in the work you completed today!
Your teacher will have told you to do one of the following:
Upload any digital documents you created and any photos you took of your written work to your Learning Management system (MS Teams, Google Classroom for example).
Email any digital documents you created and any photos you took of your written work to your teacher.
Make sure you keep any hand written work you did in your exercise book or folder as your teacher may need to see these when you are back in class.
Student reflection
Student reflection
Show how do you feel about today’s learning.
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