Unit Title: Solar Cars

Lesson Title: Gear Ratios, Kinetic Energy and Forces

Date Developed/Last Revised:

Lesson Author(s): John Constantinou, Kara Suzuka

Lesson #: 2

Grade Level: Middle School

Primary Content Area: Math, Science

Time Frame: 2 hours

PLANNING (Steps 1, 2, & 3)

1. Standards/Benchmarks and Process Skills Assessed in this Lesson:

● 6.RP.A.1: Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities.

● 6.RP.A.2: Understand the concept of a unit rate a/b associated with a ratio a:b with b ≠ 0, and use rate language in the context of a ratio relationship.

● MS-PS2-2: Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object.

● MS-PS3-1: Construct and interpret graphical displays of data to describe the relationships of kinetic energy (KE) to the mass of an object and to the speed of an object. (KE = 1/2 mv^2, but the clarification statement and evidence statement, it isn't mandatory that they get to the final equation, just the proportionalities between KE to m, and KE to v^2)

2A. Criteria- What Students Should Know and Be Able to Do:

Students can-

● Use information from their investigations to determine the effects of gear ratios on power and speed for cars, bikes, etc.

● Use ratio language to describe a relationship between 2 quantities (speed =d/t, and gear ratios)

● Describe the relationship of KE to Mass and speed● Describe the forces acting on the car. F=m*a

2B. Assessment Tools/Evidence:

Formative:

● Ratio Pre-Assessment: https://goo.gl/cYpiRV● Science Kinetic Energy Pre-Assessment: https://goo.gl/ZSEsHJ

Summative: Can use the formative pre-assessment as a post assessment to measure student learning

3. Learning Experiences (Lesson Plan)

Materials:

● Gear Investigation Car from STEM Pre-Academy (Insert Link), with different gear ratios

and movable motor. http://kelvin.com/kelvina-gear-car-kit/

● Timers● Balance● Weights to add to cars (fishing lead works well)

Handouts/Other Resources: (please attach copies)

● Gear ratio background information powerpoint● Photo of axle and gear setup● Gear Generator (simulator)● Gear Basics (Video)● Gear ratio test car build● The story of kinetic and potential energy Video: https://www.youtube.com/watch?

v=7K4V0NvUxRg● Kinetic Energy Resources- Energy Skate Park Simulator:

● https://phet.colorado.edu/en/simulation/legacy/energy-skate-park

Procedure:

● Investigation: Gear Ratio Kinetic Energy, Force and Investigation● Students will measure mass and speed/acceleration of their cars to explain the

relationship of KE to speed and mass and how an object’s motion depends on the sum of the forces on the object.

● Students will use knowledge from the investigations on Solar Panels and Gear Ratios to engineer a solar powered car that can travel quickly on flat ground without a load and

modify the car to carry a load (lead fishing weights). Engineering Design of Solar CarHomework Activity (Optional):

● Look for other simple machines around the home that use gears.● Make a list of machines that use gears and describe:

o The gear ratioo The purpose for using gears for the specific application. Explain the

“mechanical advantage” that using gears provides for the machine’s application.