Roller Coaster Design for Teachers
Introduction to the Roller Coaster design project
Step 1: Specifications and Constraints
Specifications (what the design must do)
1) Design and build a track with at least two hills, a loop and straight final run.
2) Write a program to determine the average speed of the marble from start to finish.
3) Ensure that the marble stays on the track for the duration of the run.
Step 1 (continued): Constraints
Constraints (things that limit your solution)
Use of foam insulation
Limited class time for designing and testing
The height of the initial hill affects the overall ride outcome and is limited by the space available.
The curvature of the foam loop is critical to the marble’s ability to stay on the track.
The length of the track is determined by the amount of track provided. 6. Disjointed/incomplete connections between foam pieces of track will disrupt the passage of the marble.
Materials Required
Sturdy base for first starting surface
Tube or can with one closed end (ex. oatmeal canister, Pringles™ or juice can)
Foam pipe insulation
Duct tape
Hummingbird Bit controller, batteries, sound sensor and connected laptop computer
Internet connection
Hot glue gun and glue sticks
Scissors or Canary shears
Marbles
Metric tape measure or meter stick
Graph paper
Markers/Art Supplies to decorate the roller coaster (optional)
Stopwatch and calculator (optional)
Teachers: Before you go any further…
● Practice using the sound sensor/LED setup in the tutorial at https://learn.birdbraintechnologies.com/hummingbird bit/snap/program/16-1
● NOTE: This will be used later in KSB 3 but it is VERY WORTHWHILE to test the sensor to see that it works and know how it works.
Step 2: Research and Investigate: Knowledge and Skill
Builders (KSBs)
KSB 1 Preliminary Design and Initial Measurement
Before building with students, measure the total length of the roller coaster design in meters. Keep this measurement in mind when planning:
1) where to locate the starting surface, first hill, loop, second hill and flat end section,
2) the layout of your classroom or workspace,
3) whether to have students work in teams. How many models in all can fit in your space?
Note: Important Design Issues to avoid frustration
Students will be eager to construct their models. Before they build however, remind them that the marble must stay on the track reliably and to the end of the run.
If you have time, make a demonstration loop and hill combination. The curvature of the loop needs to be more like an oval than a circle. If the initial hill is too steep, the marble will fall right off.
KSB 2 Potential and Kinetic Energy
Brief review from Science class:
Potential energy (PE) is the stored energy of an object due to its position and represents its "potential" to do work.
The amount of energy is determined by the object’s mass ( m), height (h), and acceleration due to gravity (g).
= m h g
To change the initial potential energy, the only value that can change is the height of the first hill. The height of the first hill is a very important value in the overall design.
PE
KSB 2 Potential and Kinetic Energy (cont.)
Kinetic energy (KE) is the energy of a moving object.
When traveling uphill, the object slows down due to the acceleration of gravity. Kinetic energy decreases and potential energy increases.
When traveling downhill, the object speeds up due to the acceleration of gravity. Kinetic energy increases and potential energy decreases, thus
Change of PE = Change of KE
KSB 3 Practice: Sound Sensor Basics
● It is a receiver that detects how much sound is around the sensor.
● Its output is a value from 0 to 100.
● This is the tutorial for coding the sensor.
https://learn.birdbraintechnologies.com/hummingbirdbit/snap/program/16-1
● The canister serves to protect the sensor from ambient noise.
● Make sure your sensor is working and practice using it.
KSB 3 Practice: Code Sound Sensor/LED pair
Once the sound sensor itself is functioning, create and test code such that:
When the sound sensor records a value greater than 70, an LED light will turn on. Example code is found in the write-up.
KSB 4 Timer Code considerations
● The distance is known (= length of track in meters).
● To find the time of travel, set a timer code element to measure how long it takes to arrive at the sound sensor.
● To start the timer: one person physically releases the marble while another starts the code.
● Hitting the canister generates a sound for the sound sensor to detect. Be careful that other sounds do not trigger the sensor. The canisterb acts as a shield.
● The code should return the timer value and the resultant velocity calculation.
The code might look like this:
● Start the code by clicking on the green flag at the same time the marble is launched.
● The timer counts the number of seconds until the sound sensor is activated and it stops counting.
● The LED “on” signals the end of run.
● The final value of the timer is the total time it takes for the marble to complete its run.
● The average velocity “speed” is then the track length/total time.
Real-life Construction Tips
1) Track: Join foam segments end to end, using duct tape on the back of each piece. Measure the total length in meters before building the coaster.
2) Design and build the launch surface. Attach foam track. Add weight to hold in place.
3) Make the initial height flexible but sturdy. You may wish to change it later.
4) Try building the loop and test with a marble. See next slide for help.
5. Help for your design…
Can your marble complete the loop?
If not, try changing the diameter of the loop or changing its shape into more of an oval. Moving the starting launch area up will increase the initial potential energy.
Once your marble RELIABLY makes
it through the loop…
6. Add Sensor and Code
Cut a small opening near the end of the canister. Hang the sound sensor down inside the canister and tape in place with wires on the outside.
Tape the canister itself down firmly, with the flat section of track leading into it.
Connect the sound sensor wires to the Hummingbird Bit.
Turn on the battery pack for the Bit. Put your computer/device nearby with Bluetooth enabled.
Make sure the person launching the marble and the code starter can see one another.
Testing the setup
This video shows one way of testing the design to this point: the surface, first hill, loop, flat section and sound sensor inside the canister/marble trap. One person launches the marble while their partner starts the code. When the marble hits the inside of the canister, its sound triggers the sensor. The code captures the amount of time the marble took from start to end, and calculates the velocity.
Step 3: Generating Alternative Designs
1) Try other first hill heights to see the effect of increasing/decreasing the initial potential energy.
2) What alterations need to be made to keep the marble on the track?
3) How would the design change if the roller coaster were to be positioned vertically along a wall versus coming out directly at a 90-degree angle?
4) “What defines a hill?” Experiment with different size and placements of the second hill and note changes in velocity.
Step 4: Choosing the optimal solution
Remember:
1) The marble must safely and consistently complete a run as it represents a human passenger.
2) The sound sensor should be triggered at the end of every run.
3) The timer should return a value at the end of every run and may be verified by stopwatch.
Step 5: Develop the prototype
● Build your final design and document any modifications.
● Take a picture or draw a complete sketch.
Step 6: Test and evaluate the prototype
● How do the code and physical model work together?
● Run several trials and record data to see if your model produces consistent results within an acceptable range.
Step 6: Test and Evaluate
Trial Run Height at starting surface = first hill (meters)
(meters per second)
Step 8: Reflection on the learning process
1) Coding challenges 2) *New* or *unexpected* things about coding 3) How sturdy and/or reliable is the final solution? If you were an investor, would you buy the rights to this product? Why or why not? 4) Did your solution meet the design specifications? Were there new constraints that should be added? 5) What name would you give your design theme?