Transcript Rockets!!! - TeacherWeb

Laws of
Motion
And
Rockets!!!
Rockets!!!
Sir Isaac Newton
 During the latter part of the 17th century.
Sir Isaac Newton laid the scientific
foundation for modern rocketry. He
organized his understandings of physical
motion into 3 scientific laws.
Newton’s Laws of Motion
1. Objects will stay at rest and objects in
motions will stay in motion in a straight
line unless acted upon by an
unbalanced force (outside force).
2. Force is equal to mass times
acceleration (F = ma or a=F/m)
3. For every action there is always an
opposite and equal reaction.
Newton’s First Law
An object at rest will stay at rest and an
object in motion will stay in motion in a
straight line unless acted upon by an
unbalanced force.
 In rocket flight, forces become balanced
and unbalanced all the time.
Newton’s First Law (cont.)
 A rocket on the launch pad is balanced.
The surface of the pad pushes the rocket
up while gravity tries to pull it down.
 As the engines are ignited, the thrust
from the rocket unbalances the forces,
and the rocket travels upward. Later,
when the rocket runs out of fuel, it slows
down, stops at its highest point and falls
back to Earth.
Newton’s Second Law
Force is equal to mass times acceleration
F=ma
 Force will be the pressure created by the
controlled explosion, Mass is the mass of
the gases used to propel it, and
Acceleration is the change in velocity.
Force is measure in Newtons
 Forces can be measured by looking at a
diagram like the one below:
15 N
 What is the net force?
 What will happen to the box?
10 N
Let’s Practice Some Math!
 We can also measure force by using,
F = ma, but what does that mean?
 Can we think of another formula we can
derive from F = ma?
 What if, someone was pushing a box with
a mass of 10g at a force of 15 N…What
would A = ?
Newton’s Third law
Every action has an equal and opposite
reaction.
 Think of a skateboard, when you initially
jump on (action) the skateboard will
move in the opposite direction (reaction)
to your force.
 What do you think is the action-reaction
in modern rockets?
The first rocket!
 One of the first devices to successfully use
the principles of rocket flight was invented
by a Greek man named Archytas.
Somewhere around the year 400 B.C. he
created a flying wooden bird propelled by
steam! (this is amazing, the use of steam as
a source of energy wasn’t invented until
1690!)
 He used the Action-Reaction principle which
is not stated as scientific law until the 17th
century!
History of rockets
 300 years after Archytas, Hero of
Alexandria invented a rocket-like
device called an aeolipile. It too
used steam as a propulsive gas.
 Hero mounted a sphere on top of
a water kettle and the thrust of
the gas caused the sphere to
rotate.
Rocket principles
 Ok, so how does a rocket work?
A rocket in its simplest form is a
chamber enclosing a gas under
pressure.
 Think of a balloon. The balloon is the
chamber, your breath or helium is the
gas, and the walls of the balloon are
keeping the gas under pressure.
Rocket principles
 What happens to the balloon when you let
the air escape?
 The difference between how a balloon flies
and how a rocket like the one on the shuttle
flies is simply how the pressurized gas is
produced.
Rockets over time
Let’s build!!!!
1. Get into teams of four.
2. Assign a team captain, engineer, data
collector, and inspector.
3. Each team will decide the following:
 Team Name
 # of wings to have on rocket
 Color and size of rocket
4. Have the Team Captain collect materials.
Building Procedure (cont.)
1. Once your Captain has decided on
materials, make sure you team has the
following:
a. PVC pipe
b. Color paper
c. Wing template
d. Drawing materials
e. Scissors
f. Tape
Building procedure
1. Decide on the size of your rocket, and
wrap the paper around the PVC pipe
tightly, but make sure it wont slide off
easily.
2. Seal the paper with tape. Make sure NO
AIR CAN ESCAPE.
3. Cut out the amount of wings you want
from the sheet.
Building Procedure (cont.)
1. Using scotch tape, only tape the body
of the wings to the rocket (it helps if
you bend the wings first).
2. Make sure you tape very well,
REMEMBER, THE MORE TAPE YOU USE
THE HEAVIER YOUR ROCKET BECOMES!!
Building Procedures (cont.)
1. Cut off any excess tape you may have
as this may cause air resistance.
2. Cut out the cone and begin to roll it
into a cone. It helps if you use your
thumb as a guide
3. THE CONE CANNOT HAVE A HOLE AT
THE TIP. Air will escape from there, and
your rocket may not fly.
Building Procedures (cont.)
1. After you have constructed a perfect
cone attach it to the top of your rocket
with tape. Seal all the edges.
2. After you have ensured your rocket is
sealed and ready for flight you may
design it and put your team name on it.
This component is part of your grade so
make sure it is presentable.
Every Team Will Need to
Complete the Following:
1. Inspect your rocket and make sure that
your team is adhering to the rules to
ensure safety
2. Have the necessary papers to record
launch information.
3. Finalize any necessary calculations to
ensure that you are building the most
aerodynamic rocket.
Let’s Fly our Rockets!
 Please, line up in a straight line with all
of your materials.
 Ensure that you have your:
 Rockets
 Altitude Tracker Tool
 Pencil
 Lab Data Chart