MS: NGSS - FREE CER Practice: Forces & Motion

Help students write science explanations that truly explain. This free resource gives middle school students structured practice writing Claim–Evidence–Reasoning (CER) responses using short forces-and-motion scenarios.

Students progress from a guided example to independent practice, a real-world application, and a Newton's Third Law challenge. Throughout, they build the most important CER skill: reasoning explains the science behind the evidence rather than repeating the data.

What Students Do

• Scenario 1, Pushing a Toy Car (guided): Write a CER as a class using push strength and distance data.
• Scenario 2, Same Push, Different Mass: Use numerical data to explain how mass affects motion.
• Scenario 3, Riding a Bike: Explain speeding up and slowing down using unbalanced forces and friction.
• Scenario 4, Balloon Release (challenge): Apply Newton's Third Law to an action–reaction force pair.
• Critique a CER: Compare a weak and a strong response, then revise the weaker one.
• Optional Honors Extension: Write a respectful rebuttal and identify force pairs.

What's Included

• Teacher guide: a 45-minute lesson flow, indicators of student understanding, common misconceptions with suggested responses, a scoring guide, and an NGSS standards page
• Standard student version: four scenarios, Think Like a Scientist questions, a CER Checklist, Critique a CER, and the Honors Extension
• Modified student version: the same four scenarios with sentence frames, word banks, light and heavy labels, and multiple-choice items, so the whole class can discuss the same content
• Two answer keys: the standard key gives Meets, Approaching and Needs Development examples for every scenario, and the modified key shows the completed frames

Built-In Differentiation

• English learners: the Modified version, word banks, acting out each scenario, and drafting in the first language
• Neurodivergent learners: one scenario per page, color-coded C/E/R, the Checklist used step by step, and typed or dictated responses
• Gifted and honors students: rebuttals, revising weaker CERs, and writing original scenarios for a partner

Standards

Aligned to NGSS MS-PS2-2, with a connection to MS-PS2-1. It also builds the NGSS practices of Constructing Explanations and Engaging in Argument from Evidence.

Ideal For

Practice before a lab write-up or performance task, review before a unit test, substitute plans, or homework.

Continue Building on This Resource

• Forces and Motion: Investigating Interactions and Collisions (Complete Unit)

A 15-lesson NGSS unit (MS-PS2-1, MS-PS2-2) with:

• labs and stations, graphing, and an engineering design challenge
• a CER presentation
• exit tickets, an end-of-unit assessment, and answer keys
• differentiation in every lesson

• Newton's Laws Lab Bundle + Friction

Four hands-on, NGSS-aligned labs:

• Tablecloth Pull Challenge (First Law)
• Rubber Band Launch (Second Law)
• Balloon Hover Disc (Third Law)
• Sliding Surface Lab (friction)

Each lab includes a teacher guide, a student lab sheet, an answer key with CER examples, and differentiation for diverse learners.

Questions or feedback? Contact NextWave Science at nextwavescience@gmail.com. If this resource was helpful in your classroom, a review is always appreciated.