Rockets!!! Laws of Motion And Rockets!!!

Sir Isaac Newton During the latter part of the 17 th 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: What is the net force? What will happen to the box? 15 N 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 17 th 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