seesaw images

A see-saw is a lever with the FULCRUM in the middle. A fulcrum is the word for the point about which the lever moves, or better rotates…

When there are the same number of children of the the same weight at each end of the equally long lever armS, then the see-saw is balanced.

A small force, or kick-off, by the  lower group moves the see-saw up and lowers the other group,

Up and down and up again, great fun.


Oh, Oh, the left kid is a bit mean. If he lets go, the other kid will fall down, that’s why he looks a little worried.




A pair of pliers are two levers put together at one fulcrum.

Don’t stick your finger in the short end of the pliers while you squeeze the handles…Ouch.

These two levers give you extra strength or MECHANICAL ADVANTAGE. It is a great tool to squeeze bits of metal together, or to grab a nail and pull it out of the plank…  


Now this is  joke.

The little girl balances the fat man, but it is not a real man, just a cutout or a mannequin.

If it was real, then the heavy man should sit much closer to the fulcrum or center of the see-saw and the girl should sit much farther away from the fulcrum so she has enough mechanical advantage to balance the weight of the man…

lever seesaw 425_web-ere-seesaw-par116898


How to pull a plank from another plank or beam? Use a crowbar.

lever crowbar

Use a hammer to drive the crowbar underneath the plank and then push the crowbar back. 

It pivots around the bend end, which is like a fulcrum, and because the handle is so long…

it is a lever that gives you mechanical advantage and you can lift the plank

and nails with little effort!

You can do more or less the same with this claw hammer.

lever 800px-claw-hammer

The handle is the LEVER, the head hammer is the fulcrum and claw is the shorter lever.

The handle give you the mechanical advantage.

Can you make a guess what the mechanical advantage is?

4 to 5 times maybe?

The longer lever arm is about four to five times the shorter lever arm…



lever dollies

Carts  to move large pieces of furniture or big boxes work with MECHANICAL ADVANTAGE…

The wheels are the fulcrum, the short lever picks up the box and the long handle is the longer lever. 

Look, it works this way…

A man moves a fridge he bought in Caracas after President Maduro took over shops to ease shortages

How many of these “lever-carts” or furniture “dollies”  do you see in the picture?


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