Start by reviewing forces: a force is a push or a pull that makes things move, stop, or change direction.
Show the materials for the lever experimentation, and define the parts of the lever.
Ask students to project foil balls, while varying fulcrum position, and to use the worksheet to record how high the foil ball projects with different fulcrum positions.
Conclude that the direction of the force is changed: we push down on the lever and the foil ball goes up. Conclude that one end of the lever moves more than the other when the fulcrum is off centre.
Show larger levers where students can feel the force with several smaller versions of the see saw activity in the centre of the carpet.
Conclude that when the lever end moves over a smaller distance, there is a greater force.
In some levers, the force in and out are not in opposite directions.
Everyday levers activity, with worksheet.
Discuss incllned planes and wedges:
Some of these tools also took advantage of another kind of simple machine - a wedge.
A wedge is a sloped or pointed surface - it is longer, but easier to move along it.
Which ones also have a pointed edge: scissors, staple. Scissors a compound machine.
Where is the wedge on each of these: knife, potato peeler, cheese grater, pencil sharpener….
Would it help if only one of the edges is sloped? Yes. Wedge is two inclined planes back to back.
Car can drive up a slope, but not straight up- smaller force over greater distance.
A screw is an inclined plane. Jar lid. Light bulbs.
The wheel is another simple machine.
Wheel and axle activity
Summarize that simple machines transform between a smaller force moving over a greater distance and a larger force moving over a smaller distance. They can make jobs easier.
Several simple machines linked together make a complex (or compound machine).
Move outside for the simple machines in a bike activity.
After introducing the concept of a pulley on the bike, do one of the pulleys activities.
Pulleys and forces activity for younger students, who work in groups of 3.
Pulleys to pull yourself up for older students that can follow instructions to use the system safely, and can wait for their turn.