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West Chester Area School District, East Goshen Elementary School Keystone teacher Bill Turner took some digital photos of science in action and shared his class' experiences studying rockets. Bill relates his tale of the investigation below. See Bill's class explore chemical reactions too. Rockets
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In third grade we have a science unit called Wings
and Rockets. We learn all about flying things.
Towards the end of the unit as the end of the school
year approaches we begin to learn how rockets move. I
do a very simple demonstration with my students to
help them understand Newton's Third Law of Motion.
One child sits on my "Newtonian Demonstration
Device." (Well, if I had called it a skateboard when
I bought it, the school would NEVER have reimbursed
me for it.…) Another child stands on it and
jumps off. The skateboard rolls forward a little.
We talk about why the jumper went further than the
skateboard and the sitting child. Someone always asks
what would happen if I (the teacher) jumped off. We
do that little demonstration, too. Since I'm a lot
bigger than my students, the child and the skateboard
go a lot further. From this demonstration it is a
short trip to explaining how the force of the exhaust
from a rockets engine imparts an equal force in the
opposite direction on the body of the rocket.
Although each particle of exhaust is very small,
there are a very large number of them and they are
moving very quickly.
We then begin to design a series of different kinds of
rockets over a number of days. We start with straw rockets,
which are nothing more than a large straw over a smaller
diameter straw.
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By blowing into the smaller straw the straw rocket
shoots off its "launch pad" and into the air.
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And, of course, you can do many launches at a time! (But it
helps if no one else is using the halls!)
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As is always the case, the children want to make their
rockets go further and stay up longer. We discuss ways to do
that. Then I bring out my "toilet plunger rocket" launch
pad.
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I explain that we can make our rockets go even further by
using a
greater force to launch them. Of course, since the force is
greater, the rockets have to be larger and must be able to
withstand a greater force when they are launched. They must
also be designed to fly through the air as well as space. We
discuss aerodynamics at this point. I make sure the students
understand that rockets are only shaped the way they are so
they can fly through the air to get to space. Once they're
in space, a rocket can have any shape at all!
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When everyone has completed their rocket we head outside to
launch them. With a good "plunge," the average rocket will
go 60 to 70 feet. This is a great opportunity to record each
rocket's travel distance and work on our graphing skills. We
examine the rockets that flew the furthest and come up with
reasons for their successful flights.
Our next (and this year's final) rocket activity involves the use of a more powerful fuel: alka seltzer! The students put a spoonful of water in a small vial, add a tablet of alka seltzer, quickly put the top on, and then wait for the pressure to build to launch their rocket. Sometimes, they remember to add the nose cone BEFORE the launch! Next year, we do water rockets! |
