Hi, kids!
Welcome to a new weekly Science Lab video.
We’re moving on!
Let's get into the basics of applying scientific
knowledge to everyday life; it's time to dive
into the exciting world of technology.
Let's talk about simple machines.
A simple machine is a device that makes work
easier by changing the direction or the intensity
of a force, which means that they allow us
to do work with less effort!
Simple machines have been used since ancient
times to facilitate, among other things, the
building of great monuments that have lasted
until today and that, if it were not for them,
would never have existed.
Although they had already been in use for
a very long time, the Greek scientist and
inventor Archimedes was the first one we know
of, some 2200 years ago, who studied simple
machines as such.
He identified three simple machines: the lever,
the pulley and the screw.
This time, we'll focus only on the lever.
Archimedes explained that levers provide a
mechanical advantage, meaning that using them
would allow a person to move something that
would normally be too heavy to move.
On one occasion, he reportedly went so far
as to say:
Give me a lever long enough and a fulcrum
on which to place it, and I shall move the
world.
That's all well and good, but what's a lever?
And what in the world is a fulcrum?
A lever is a tool like a rod or bar that rests
and turns on a fixed support called a fulcrum.
When a lever is used, a small force is applied
over a long distance, and the lever turns
it into a larger force over a shorter distance.
Three types, or classes, of levers can be
distinguished, which simply differ from each
other in the relative position of the fulcrum
and the applied force with respect to the
resulting force.
Thus:
Class 1 levers are those in which the fulcrum
is placed in a central position with respect
to the applied and resultant forces.
An example of this type of lever would be
a seesaw.
Class 2 levers are those in which the resultant
force is in a central position with respect
to the applied force and the fulcrum.
An example of this type of lever would be
a wheelbarrow.
Class 3 levers are those in which the applied
force is in a central position with respect
to the resultant force and the fulcrum.
An example of this type of lever would be
a tweezer.
In this image you can see that there are many
more examples of levers of each class and,
if you stop to think about it, we are really
using levers of all three classes continuously
in our day to day.
It’s not that difficult, right?
Let’s put it to test!
Find an example of a lever from each class,
which I'm sure you have several in your house,
and experiment with them.
Identify their fulcrum and where the applied
and resulting forces take place.
I look forward to seeing your creativity at
work with those levers!
I hope you enjoyed this activity.
See you!
