Newton’s Laws & Rocket Building…

1. Newton’s Laws &Rocket Building… 8/8/2014

2. Today’s Warm-up • Quick review:Newton’s Three Law’s of Motion • Water rocket video clips • And the same concept, but MythBusters style… • And a crazy clip from somewhere in Asia…

3. Today’s Warm-up Quick review (for candy!)

4. Grade Six-Weeks Exam F A F D J C G D G D H A • C • H • B • J • A • H • C • J • A • J • B • G • B

5. Water Rockets • Description: • The water rocket uses air pressure to force water out the mouth of a pop bottle. The momentum of the expulsed water causes the rocket to lift off. • Theory: • Have you ever seen a cannon fire before? As the projectile leaves the barrel of the gun, the gun recoils from the blast. That effect (the recoil) is the same effect that enables rockets to lift off. Simply put, a rocket has two basic elements: a body, and fuel, which is stored in the body. The fuel has mass, so as it is blown out the bottom of the rocket, it causes the body to recoil upwards. If the body is forced hard enough upwards, it can lift off - up off the ground, up into the sky, and (in the case of space rockets) up into outer space! To get the strongest upwards lift, you basically need to do two things: 1) blow a large mass of fuel out the bottom, and 2) blow that fuel out very quickly. Oh yeah - and it's easier launch a light rocket, so the less mass the body has, the better.

6. Water Rockets • Description: • The water rocket uses air pressure to force water out the mouth of a soda bottle. The momentum of the expulsed water causes the rocket to lift off. • Theory: • You can sum up these ideas nicely with the idea of "momentum". The momentum (p) of an object is its mass (m) times it's velocity (v): p = mv • So the more momentum the fuel has as it's being ejected, the faster (and higher) the rocket will lift off. The rocket in our demo is a pop bottle filled part-way with water. The mouth is plugged with a rubber stopper or pvc pipe outlet, and a bicycle pump and inflator pin are used to pressurize the bottle. When the air pressure builds up enough, it forces the plug and the water out the mouth of the bottle, and the recoil fires the bottle into the air.

7. Water Rockets • Water rockets utilize Newton’s Third Law of Motion… • The fuel is pressurized air and water • The rocket itself is a 1 or 2-liter soda bottle • Today we’ll launch just the bottle itself, but…

8. Water Rockets The rockets made from these bottles are surprisingly powerful. A standard 2-liter pop bottle 1/3 full of water, pumped to 80 psi and then released, will eject all its water in less than one-tenth of a second, and at that point ("burnout") will be only about 2 meters off the ground. Amazingly, its velocity at burnout is around 76 meters per second. That's over 170 miles per hour! This means the average acceleration during thrust is 111 g's! Yowza. Safety rule number 1: Never get in the way of one of these rockets... A plain bottle is of course aerodynamically hopeless, and tumbles fluffily after burnout, rarely going higher than 60 or 70 feet. But if you add fins and nose weight, transforming the bottle into an aerodynamically stable rocket (see rocket theory), then all that initial thrust can be transformed into truly amazing altitudes of over 300 feet. You really have to see it to believe it.

9. Water Rockets • You will find that design options like fins and nosecones improve flight time, sometimes by quite a bit…

10. Water Rockets • Let’s get tobuilding rockets!

11. Water Rockets- 2008 IPC class

12. 2009 Rocket Review

13. Make it a great day Mustangs!