This project is great for helping students illustrate the ancient Roman chariot races that were a big part of this civilization. It contains an experimental component where student partners will use design concepts and manipulation of Newton's second law of motion (F=ma) to create wheels that will attach to a model of a chariot provided to them to race against another team. The chariot will be harness a Sphero "horse", and a student driver will use the Sphero iPad app to race the chariot.
This project will help students gain an understanding of Newton's Second Law of Motion. With the Sphero providing a standardized "horse" for force, the student is left to design wheels to reduce mass. This should lead to faster acceleration, better response, and speed for racing the chariots.
1'8" steel rod or a #6-32 threaded rod can be used to substitute the snapping stud axles. The axles can be carefully cut-off, and a through-hole should be drilled through the back of the chariot. Locking nuts and washers should be used if you go this route. The retaining fasteners should not prevent the wheels from turning.
Team Designers: Leonard Evansic and Danny Gonzalez; Design Writer: Blanca Herrera
We saw several existing chariots for the Sphero in the Thingiverse, but wanted to create one that would offer an easy design component for a classroom setting. We designed what we felt would be the minimal mass frame for attaching custom wheels. A ring harnessing the Sphero is held to a constant height by a post that drags behind the Sphero for a minimal amount of drag. By minimizing the mass of the chariot frame, the effect of wheel mass on overall performance will be more apparent.
We added an optional charioteer, if you want to have an ancient roman avatar onboard. The chariot, charioteer, and "flame" wheels were designed in OnShape cloud-based CAD.
It is intended that students will be designing their own wheels in TinkerCAD. The provided set of "star" wheels was designed in TinkerCAD. Any wheels with a hub bore of 4 mm, a hub thickness of 6 mm, and a diameter in the range of 70-80 mm should work well with this project.
Student will experiment using the formula F=ma to determine the best model for a chariot that will be propelled by a Sphero controlled by the iPad app.
Students will learn:
Teamwork & Collaborative Design
3D CAD Design
How to create a model to demonstrate Newton’s first law of force f=ma and the use of chariots during Roman ancient civilization.
Students in grades 6th-8th
Science & Design
Skills Learned (Standards)
PS2.A: Forces and Motion
For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction (Newton’s third law). (MS-PS2-1)
The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. (MS-PS2-2)
All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared. (MS-PS2-2)
ETS1.A: Defining and Delimiting Engineering Problems
The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions. (MS-ETS1-1)
ETS1.B: Developing Possible Solutions
A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. (MS-ETS1-4)
There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. (MS-ETS1-2), (MS-ETS1-3)
Sometimes parts of different solutions can be combined to create a solution that is better than any of its predecessors. (MS-ETS1-3)
Models of all kinds are important for testing solutions. (MS-ETS1-4)
ETS1.C: Optimizing the Design Solution
Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process—that is, some of those characteristics may be incorporated into the new design. (MS-ETS1-3)
The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. (MS-ETS1-4)
Modeling and Using Tools
Model with mathematics.
Use appropriate tools strategically
Expressions and Equations
Apply and extend previous understandings of arithmetic to algebraic expressions.
Represent and analyze quantitative relationships between dependent and independent variables.
6th. Grade: Students analyze the geographic, political, economic, religious, and social structures during the development of Rome.
Discuss the legacies of Roman art and architecture, technology and science, literature, language, and law.
Students will work in pairs to design their wheels
Students will sketch their design by hand
Students will use design software such as TinkerCad to design their chariot wheels
Students will use a 3D printer to print a model of the chariot wheels.
Students will race their Sphero chariot to see which one moves the fastest.
Student will write a reflection on the results of the race and what factors contributed to the speed of their Sphero chariot.
Sphero - http://www.sphero.com/
Teachers need to print out 2 identical chariot rings that are provided.
Teachers need to acquire 2 Sphero robots
Teachers need to explain the formula of f=ma to give background information to students, so they can understand the effect of each variable. In this activity the force and the acceleration are constant.
In Thing Files
NGSS Standards: http://www.nextgenscience.org/
CA Standards: http://www.cde.ca.gov/be/st/ss/