ROCKET LESSON

General Background

After reading the background information please write a response that identifies 5 key factors in building a rocket.
This must be turned in your blue book journal at the end of class.

TEST

HOMEWORK ASSIGNMENT

There are four basic forces operating on objects in flight such as a rocket.

They are gravity, thrust, drag and lift.

Gravity is the force that pulls all objects toward the center of the earth. The

amount of this force is proportional to the mass of the object.

Thrust is the force that propels the flying object.

Drag is the force acting on an object moving through a fluid. Since air and

water are fluids, drag is the resistance that the object encounters as it moves

through the fluid.

 

Lift is the force that is directed opposite to the force of gravity produced by

the shape and position of a body moving through a fluid. An object moving

in a vacuum produces no lift. Lift is generated by an object moving through

a fluid if the object’s shape causes appropriate reactions as the object moves

through a fluid.

 

Newton’s three Laws of Motion are concepts essential to understanding

rocket flight. The laws will be an integral part of the lessons in this unit.

The laws are as follows: 1. A body at rest will remain at rest, the body in

motion will continue in motion with a constant speed in a straight line as

long as no unbalanced force acts upon it. This law is often referred to as the

law of inertia.

 

2. If an unbalanced force acts on a body, the body will be accelerated; the

magnitude of the acceleration is proportional to the magnitude of the unbalanced

force, and the direction of the acceleration is in the direction of the

unbalanced force.

 

3. Whenever one body exerts a force on another body, the second body exerts

a force equal in magnitude and opposite in direction of the first body. This

law relates to the principle of action-reaction.

Lesson 1 (One Day)

Learning About Motion and Flight With a Model Rocket

Objective of the Lesson:

The student will be able to:

• Identify and trace the basic path of a rocket from launch to recovery.

• Describe how Newton’s Third Law of Motion relates to launching a

model rocket.

• Begin the construction of a rocket by assembling the engine mount.

• Recognize and define vocabulary.

Screen Shot 2016-03-28 at 10.42.22 AM Screen Shot 2016-03-28 at 10.38.51 AM

BACKGROUND 

Thrust is the upward force that makes the rocket accelerate upward. This is a

demonstration of Newton’s Third Law of Motion : “For every action there is

an equal and opposite reaction.” The action is the gas escaping through the

nozzle. The reaction is the rocket accelerating upward. The rocket will continue

to accelerate until all of the propellant in the rocket engine is used up.

The casing of a model rocket engine houses the propellant. At the base of the

engine is the nozzle, a heat-resistant, rigid material. The igniter in the rocket

engine nozzle is heated by an electric current supplied by a battery-powered

launch controller. The hot igniter ignites the solid rocket propellant inside

the engine which produces gas while it is being consumed. This gas causes

pressure inside the rocket engine, which must escape through the nozzle. The

gas escapes at a high speed. This produces thrust.

 

Above the propellant is the smoke-tracking and delay element. Once the propellant is

used up, the engine’s time delay is activated. The engine’s time delay produces a visible

smoke trail used in tracking, but no thrust. The fast moving rocket now begins to

decelerate (slow down) as it coasts upward toward apogee (peak altitude). The rocket

slows down due to the pull of gravity and drag. Drag is the force that resists the forward

motion of an object through the air.

 

When the rocket has slowed enough, it will stop going up and begin to arc over and

head downward. This high point is the apogee. At this point the engine’s time delay is

used up and the ejection charge is activated. The ejection charge is above the delay

element. It produces hot gases that expand and blow away the cap at the top of the

engine. The ejection charge generates a large volume of gas that expands forward and

pushes the parachute out of the top of the rocket. The parachute now opens and provides

a slow, gentle and safe landing. The rocket can now be prepared to launch again!

VOCABULARY Test Next Class

Accelerate: Speed up.

Gravity: The force that pulls all objects to the center of the Earth.

Apogee: The peak altitude a rocket reaches when it is farthest from the

surface of the earth.

Igniter: An electrical device that ignites the combustion of the propellant

in a model rocket engine.

Decelerate: Slow down.

Launch: The lift off of a model rocket following the ignition of the

engine.

Delay Element: Ignites after the propellant burns out and is an aid in

tracking the rocket and in providing a time delay during which the rocket

coasts to apogee.

 

Propellant: A mixture of fuel and an oxidizer which is the source of

motive energy in a rocket.

Drag: The force that resists the forward motion of an object as it moves

through the air.

Recovery System: The device in a model rocket whose purpose is to

return the rocket to the ground safely by creating excess drag or by

creating lift.

Ejection Charge: Ignited by the delay element and produces expanding

gases which activate or eject a recovery device.

Thrust: The force that makes the rocket accelerate upward as the propellant

is burning.

After watching the video, students should identify 10-15 key points in the video.