1. Catalyst

2. Today’s Agenda Catalyst Project Intro How Roller Coasters Work
5 min
Catalyst
Project Intro
30 min
How Roller Coasters Work
Exit Slip

3. Roller Coaster Project
This week we are focusing on a cumulative group project for this unit – building your first roller coaster  Today we’re going to focus on the theory behind it.

4. Schedule for the Week DAY ACTIVITY Monday Intro to Project
Group Responsibilities
Roller Coaster Theory
Tuesday
Design
Promo Posters
Construction Prep
Wednesday
Construction
Thursday
Finalize Construction
Begin Worksheet
Friday
Finalize Worksheet
Presentation Prep
Groups Present
Grading

5. Group Responsibilities
This project relies on you all working as a TEAM. Those that do not do so will receive low grades on this project per the rubric that is on page 8 of your packet.
At the end of class on your exit slip, you will write the name of ONE person you would like to work with on this project. Then Prof. Myers will match you with another partner group to form a group of 4

6. Roller Coasters
What have been your favorite roller coasters? What have been the characteristics of the roller coaster including the hills and loops? Describe what you loved/hated about it?
If you have never been on one, describe some of the ones you have seen.

7. Today’s Agenda Catalyst Project Intro How Roller Coasters Work
5 min
Catalyst
Project Intro
30 min
How Roller Coasters Work
Exit Slip

8. HOW DO ROLLER COASTERS WORK???
Hint: If you think there’ s a little engine that pushes them along, that is NOT the answer

9. Roller Coaster Mechanism
Think about a roller coaster that starts with a big hill.
In the middle of the track on that first hill, there's a chain that you can see if you look closely enough.
That chain hooks on to the bottom of the cars and pulls them to the top of that first hill, which is always the highest point on a roller coaster.
Once the cars are at the top of that hill, they are released from the chain and they coast through the rest of the track, which is where the name roller “coaster” comes from

10. Demo
What do you think would happen if a roller coaster had a hill in the middle of the track that was taller than the first hill? Would the cars be able to make it up this bigger hill using just gravity?

11. The Physics of Roller Coasters
The next few slides will go through the physics of roller coasters covering important information to help you all design, build and analyze your coasters
You fill in the blanks!

12. Law of Conservation of Energy
Energy cannot be created or destroyed only transferred from one form to another!
The two forms coasters use are kinetic energy and gravitational potential energy

13. Law of Conservation of Energy
Energy cannot be created or destroyed only transferred from one form to another!
The two forms coasters use are kinetic energy and gravitational potential energy
PEG is greatest at the HIGHEST point (more height, more energy) and least at the LOWEST point

14. Law of Conservation of Energy
Energy cannot be created or destroyed only transferred from one form to another!
The two forms coasters use are kinetic energy and gravitational potential energy
PEG is greatest at the HIGHEST point (more height, more energy) and least at the LOWEST point
KE is just the opposite greatest at the LOWEST point (greatest speed) and least at the HIGHEST point

15. Law of Conservation of Energy
Energy cannot be created or destroyed only transferred from one form to another!
The two forms coasters use are kinetic energy and gravitational potential energy
PEG is greatest at the HIGHEST point (more height, more energy) and least at the LOWEST point
KE is just the opposite greatest at the LOWEST point (greatest speed) and least at the HIGHEST point
There are points where the roller coaster has ONLY PE or ONLY KE but most of the time it has BOTH!

16. The First Hill
The first hill of a roller coaster is always the highest point of the roller coaster because friction and drag immediately begin robbing the car of energy.
At the top of the first hill, a car's energy is almost entirely gravitational potential energy (because its velocity is zero).
This is the maximum energy that the car will ever have during the ride. That energy can become kinetic energy (which it does at the bottom of this hill when the car is moving fast) or a combination of potential and kinetic energy (like at the tops of smaller hills), but the total energy of the car cannot be more than it was at the top of the first hill.
If a taller hill were placed in the middle of the roller coaster, it would have more gravitational potential energy than the first hill, so a car would NOT be able to get to the top of this taller hill!

17. Where’s Your Coaster Going to Be FASTEST?
Where do you think the roller coaster will be the fastest???

18. Where’s Your Coaster Going to Be FASTEST?
Cars in roller coasters always move the fastest at the bottom of hills. This is related to the first concept in that at the bottom of hills all of the potential energy has been converted to kinetic energy, which means more speed.
Likewise, cars always move the slowest at their highest point, which is the top of the first hill.

19. Online Simulation
This simulation shows the relationship between vertical position and the speed of a car in different roller coaster shapes.

20. Roller Coaster Limitation #1
Friction exists in all roller coasters, and it takes away from the useful energy provided by roller coaster.
Friction is caused in roller coasters by the rubbing of the car wheels on the track.
Friction turns the useful energy of the roller coaster into heat energy, which doesn’t help move the car along the track.
Friction is the reason roller coasters cannot go on forever, so minimizing friction is one of the biggest challenges for roller coaster engineers.
Friction is also the reason that roller coasters can never regain their maximum height after the initial hill unless there is a second chain lift somewhere on the track.

21. Roller Coaster Limitation #2
Cars can only make it through loops if they have enough speed at the top of the loop.
This minimum speed is referred to as the critical velocity, and is equal the square root of the radius of the loop multiplied by the gravitational constant (vc = (rg)1/2).
Don’t worry about this formula!!!!!!
Just understand that if a car is not moving fast enough at the top of a loop it will fall 
In real life, most roller coasters have wheels on both sides of the track to prevent them from falling for safety reasons. Your coasters will not have that though.

22. Roller Coaster Limitation #3
This one isn’t important for YOUR coasters but a fun fact 
Most roller coaster loops are not perfectly circular in shape, but have a teardrop shape.
Roller coaster designers discovered that if a loop is circular, the rider experiences the greatest force at the bottom of the loop when the cars are moving fastest. A bunch of people got neck injuries with the circular model so they had to change it.
With the teardrop shape, the radius of of the loop is widest at the bottom, reducing the force on the riders when the cars move fastest, and smallest at the top when the cars are moving relatively slowly. This gave a smoother, safer ride and the teardrop shape is now in use in roller coasters around the world.

23. G-Forces
Riders may experience weightlessness at the tops of hills (negative g-forces) and feel heavy at the bottoms of hills (positive g-forces). This feeling is caused by the change in direction of the roller coaster (acceleration!)
At the top of a roller coaster, the car goes from moving upward to flat to moving downward. This makes the riders feel as if there is a force acting on them, pulling them out of their seats.
G-Force Less Than 1
At the bottom of hills, the riders go from moving downward to flat to moving upward, and feel like there’s a force pushing them down into their seats.
G-Force Greater Than 1
These forces are called gravitational forces, or g-forces.

24. Tomorrow…. We Design!
Tonight you should start looking up your favorite types of roller coasters!

25. Today’s Agenda Catalyst Project Intro How Roller Coasters Work
5 min
Catalyst
Project Intro
30 min
How Roller Coasters Work
Exit Slip

26. Exit Slip
1. Write down the name of ONE partner you would like to work with on this project. (Be sure to write your own name as well!)
2. Where do roller coasters have the maximum potential energy?
3. Where do roller coasters have the maximum kinetic energy?