Gravity Racers

Dawn Renee Wilcox, Shannon Roberts, and David Wilcox Science & Children (NSTA)
Type Category
Instructional Materials
Simulation , Experiment/Lab Activity , Activity
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



Through experimentation and active investigation of motion and forces, students are challenged to design, build, and test a simple gravity-powered car that is at least 8 cm wide and less than 30 cm long.  The completed Gravity Racer should be able to roll down a ramp and travel for at least 100 cm. Prior to designing the 'Gravity Racer', students are exposed to the 5E learning cycle model (Engage, Explore, Explain, Elaborate, Evaluate), where they will investigate how forces act upon various objects, collect data and then apply what they learned to their racers.  

Intended Audience

Educational Level
  • Upper Elementary
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

3-PS2-1 Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.

Clarification Statement: Examples could include an unbalanced force on one side of a ball can make it start moving; and, balanced forces pushing on a box from both sides will not produce any motion at all.

Assessment Boundary: Assessment is limited to one variable at a time: number, size, or direction of forces. Assessment does not include quantitative force size, only qualitative and relative. Assessment is limited to gravity being addressed as a force that pulls objects down.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Through investigation and discovery on their own and with peers, students are encouraged to observe the motion of simple items: wheels, balls, blocks of wood, marbles, or pennies as they moved down a slope. Using data tables students then record the movement and distance of each object. It is recommended to continually ask the students questions to assess the concepts they are observing. What caused the object to stop? What made the object go faster? Slower? Does the weight of the object make it slow down or go faster? What is pulling the object down the ramp? What would happen if you push it?

3-5-ETS1-1 Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.

Clarification Statement: none

Assessment Boundary: none

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Although the words 'criteria' and 'constraints' are not used in the article, the guidelines are given to build and design a car that is at least 8 cm wide and no longer than 30 cm. Various items can be available for the students to work with: (card- stock, construction paper, tissue paper, cardboard milk cartons, dowels, paper clips, pipe cleaners, straws, wheels, Styrofoam trays, spools, craft sticks, plastic bottles, glue, tape, scissors). It is recommended for the teacher to give a 'constraint' on these items by possibly limiting some of the items. The completed Gravity Racer should be able to roll down a ramp and travel for at least 100 cm. After planning and sketching the design for the car, the students are given time to build, test and make design modifications and adjustments to their vehicles based on their findings. The activity addresses the importance of a discussion about cause-and-effect relationships and for students to focus on these changing variables. To assess student learning during these stages, key questions could be asked: How might you get the car to stop sooner or travel faster? What is pulling the car toward the bottom of the ramp? Why did it stop? What caused the car to slow down? What would happen if you reduce the surface area of the car? Will that reduce the air resistance acting upon it?

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
It is important that students be given time to test and reflect with different objects prior to building their racers and write their predictions and changes on the worksheet provided. Encourage students to explore freely, test their predictions, and discuss their ideas about motion with their peers. Ask students: What did you change? How did your change effect the direction and speed of the car?

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
To best meet this disciplinary core idea, it is recommended that if students are struggling with the concepts of balanced and unbalanced forces, they actively engage in the simulation activity that is addressed in this lesson before they design their racers. If needed, a modified version of a push and pull activity is located under the 8-9 years old link.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
It is recommended to fully meet his crosscutting concept that students explicitly identify a cause and an effect when describing each of the force and motion relationships they have discovered with their racers. Ask students to explain how or why their gravity racer sped up or slowed down. Have them draw a model as an extension to their racer diagrams. Students could model the forces by diagramming what forces are acting on their vehicle before releasing it - while it goes down the ramp - and while it's stopping to show the cause and effect relationship.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This lesson gives students opportunities to discover, through active investigation and data collection, the evidence needed to explain the phenomenon of motion and forces prior to building their cars. Although the authors calls the car a 'Gravity' Racer, it is recommended to more fully align this lesson to the rigors of NGSS, the teacher should introduce the concept that when an object falls, air resistance acts upwards and weight acts downward toward 'gravity'.

  • Instructional Supports: The Gravity Racers activity includes helpful support available in the NSTA archive link that is given at the end of the article. There is an example of student work, a data recording sheet to be used after testing the vehicle, a list of non-fiction resources on forces and motion, as well as investigation and brainstorming worksheets for the students. The direct link to the resource materials noted is: which is different than the link noted in the article. It is recommended for students needing extra support to use the BBC interactive simulation link that is provided at the end of the article. Extension activities are included to assist students in applying the concept of forces and motion to their everyday lives outside the classroom. It is recommended that the Ed Heads activity may not be appropriate for 3rd graders due to the simulated crash scene.

  • Monitoring Student Progress: Formative assessments are embedded throughout the activity as the students are collecting and recording their data and observations. An oral communication and investigation rubric are included with the activity that allows the teacher to monitor student progress. To fully align the rubric with the three-dimensional learning of the NGSS it is suggested that the students analyze and explain the cause and effect relationships to the change in motion of the racer. A quiz on the simulation activity link: ( can be used as a summative assessment to monitor the student learning.

  • Quality of Technological Interactivity: There is a strong possibility for technological activity through the use of the simulation link the authors list under Internet Resources: In this investigation students can interact first hand with variables that may cause a change in the motion of a vehicle traveling down a slope (for ages 10-11). Students are given the opportunity to make the slope steeper and to carry lighter vs heavier loads as their vehicle travels down the slope. Students can interact with the site to investigate questions like: Why does the truck travel further with weights but less with parachutes? When the slope is steeper, why does the truck travel further in all cases? To modify the activity for 3rd grade students there is a simulation on forces and motions, specifically on friction.