Hello I'm Jared. Welcome to Fun Science
Demos. Our friends at Educational
Innovations have some really cool
science gadgets they have for sale and
today we are going to take a look at the
reaction rocket, which helps us to take a
closer look at Newton's third law of
motion. Newton's third law says that for
every action, there is an equal and
opposite reaction, so let us see that at
work. When you open the packet up you will
find a rubber ball with a straw attached
to it, and then two bigger straw rockets.
They have little foam fins and then a
little plastic collar glued to the top
of the rocket. So to take a closer look
at Newton's third law, let us just start
with the ball and the straw. Let us bring
in our meter stick and I am going to hold
the ball about 20 centimeters now when I
drop the ball there is going to be energy
in the ball as it drops and let us see
what happens once it hits the table.
So what happened there? When the ball hit
the table, well, the energy stored in that
ball as it was falling is transferred to
the table, but some of that energy is also
transferred back up into the ball,
propelling it upwards.
Now, you will notice that the ball did not
bounce back to the full 20 centimeters
Well, why? Well, because some of that
energy was transferred into the table so
there was not as much energy propelling
it back upward. Now, something interesting
happens when we add our plastic straw
rocket we really could not see the energy
that is being transferred back into the
ball propelling it upward but this
rocket is going to allow us to see that.
So I slide the rocket over the straw and
I am just going to hold it up and I want you
to watch the rocket.
You can see the rocket is propelled way higher because the
mass of the straw is not anywhere near
what it is of this ball. So the energy in
this ball propels this rocket upward.
Now, Educational Innovations is a great
website and on that website they have a
paper that goes along with this reaction
rocket, to see how this thing works and
one of their ideas is to try dropping
the rocket, dropping the ball, at
different heights and see how high the
rocket goes so we are going to try that
right now. Here is our meter stick. We are going to try dropping the rocket at 10
centimeters about 10 centimeters so
let us see how high the rocket goes.
So the rocket came up somewhere around 40
centimeters. What happens if I try
dropping the ball at 20 centimeters? How
high do you think the rockets going to
go? Let us try that again so it does not go
straight out our second drop our rocket
went a little more than 80 centimeters
so what does that mean well the higher
up that I am dropping the ball in the
rocket that means the higher the Rockets
going to go why well it is because the
higher up I dropped the ball with the
rocket the more energy it has so the
higher goes remember a part of science
is measuring things so a neat activity
would be to get yourself a meter stick
to get yourself a piece of paper and a
pencil and to try dropping the rocket
from different heights and recording how
high that goes I wonder what happens if
I would drop the route of the ball
really high up try it and find out I
wonder what would happen if I try
dropping the
ball at fifty centimeters well I can try
it and find out and that rock and about
hit the ceiling you can see it was way
higher than my meter stick so we could
have a lot of fun measuring things with
our rocket drop now I want to take a
closer look at that energy that's being
transferred so keep in mind when we drop
the ball without the rocket it comes up
a pretty decent amount now I want you to
watch how high that ball bounces up once
I have the rocket on don't watch the
rocket watch the balls height you could
see the ball barely came off the table
that is because all the energy in that
ball was being transferred to this
rocket and that is what made the rocket
go so high get your own reaction rocket
kit from Educational Innovations and try
this on your own. It is a lot of fun and
do some measuring because measuring is a
key part of science. We put a link to
educational innovations website so you
can buy your own reaction rocket! If you
want to learn more about forces in
motion or just science check out our
channel, Fun Science Demos. Science is so
cool! Thanks for watching
