Presentation on theme: "Welcome to a world full of machines! There are machines all around us!"— Presentation transcript:
Welcome to a world full of machines! There are machines all around us!
The 6 Simple Machines AllAll machines are made up of some of the 6 simple machines. They are: Wheel and axle Pulley Lever Wedge Screw Inclined Plane
Why do we need simple machines? work easier Work means that we are exerting force and moving something. The 6 simple machines make our work easier. We won’t have to use as much force with our simple machines. fooleddo But do not be fooled machines do not make less work not make less work and in almost all cases because of friction a machine makes more work.
The First Machine? The wheel & axle The wheel(s) and axle turn together as a force is applied to the wheel. Here the big wheel turns easily to lift the bucket. As the axle rotates the rope wraps around it.
Another kind of wheel is called a gear! A gear is a wheel with teeth. When one gear turns, its teeth push against the teeth of the other gear and they both turn.
Pulley A pulley is a wheel with a groove along its edge, for holding a rope or cable. The applied force is applied to the rope or line and the grooved wheels convert that force to lifting the weight.
Levers There are three parts to a lever: Resistance arm (weight) Effort arm (Force applied) Fulcrum: support & balance point
A seesaw is a lever The center support is the fulcrum, which does not move. The load is your friend sitting on one end. You exert the force at the other end trying to lift your friend off the ground. When you push down on your seat, (the force) you can lift your friend (the load) while the fulcrum acts as the pivot point, making the seesaw go up and down. A machine makes lifting your friend this way much easier than just picking her or him up!
The Wedge A wedge is used to split, tighten, or secure a hold. A wedge is usually a triangle shape with a sharp point. If you apply force at one end, the wedge will go between something, in this case an ax splits a piece of wood.
Where can we find wedges? Wedges that split: Your teeth! Every time you bite into something, you are using a wedge. Wedges that cut: A saw! A knife! Wedges that tighten: A doorstop to keep the door open. Wedges that hold things together: A nail holds wood to a wall or other wood.
The Screw The three mechanical parts to a screw: Circumference Pitch (thread space) Hieght. The shaft of a screw has ridges, called threads that wind around the screw. If it doesn’t have the threads, it is probably just a nail. (a nail is a wedge)
A screw? Fasten two things together When you turn it, the threads cut a groove in the material, making a hole. The groove holds the screw tightly in place. To remove the screw you turn it the opposite way, you can’t just pull it out.
The Inclined Plane It is a slanted surface or ramp. It makes moving objects easier. Roads, ramps, stairs or paths are all incline planes. Instead of going straight up an incline makes the job easier by using an angle, like the Pittsburgh Incline.
The 6 Simple Machines Lever Pulley Wheel and Axle Wedge Screw Inclined Plane