Unit Plan 13 (Grade 4 Science): Light, Reflection & Refraction
Grade 4 unit where students model how light travels, reflects, and refracts through materials, and explore how light energy can cause changes or motion.
Focus: Investigate how light travels in straight lines and how it interacts with materials through reflection and refraction, using models to show how light waves can cause changes and motion.
Grade Level: 4
Subject Area: Science (Physical Science — Waves, Light & Energy)
Total Unit Duration: 5 sessions (one week), 45–60 minutes per session
I. Introduction
Students explore light as a form of energy that travels in straight lines until it hits an object. Through hands-on investigations, they observe how light reflects from smooth, shiny surfaces (mirrors), scatters from rough surfaces, and refracts (bends) when passing through water, glass, or plastic lenses. Students build models to explain how light’s path changes at boundaries between materials and consider how light can cause changes or motion in objects (e.g., warming, triggering sensors).
Essential Questions
- How does light travel, and what happens when it hits different kinds of materials?
- What is the difference between reflection and refraction, and where do we see each in everyday life?
- How can models of light rays and waves help us explain how light can cause changes or motion in objects?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Describe how light travels in straight lines until it hits an object or surface.
- Investigate and model reflection of light using mirrors and shiny surfaces, showing equal angles in and out.
- Investigate and model refraction by observing how light bends when passing through water, glass, or plastic.
- Explain examples of light causing changes or motion (e.g., warming surfaces, activating a light sensor, moving a needle or meter).
- Create a Light Interactions Model Poster that combines ray diagrams and explanations for travel, reflection, and refraction.
Standards Alignment — 4th Grade (NGSS-Aligned)
- 4-PS4-2 — Develop a model to describe that waves can cause objects to move.
Success Criteria — Student-Friendly Language
- I can describe and draw how light travels in straight lines from a source.
- I can show and explain how light reflects from a mirror or shiny surface.
- I can show and explain how light bends when it goes through water or clear objects (refraction).
- I can give at least one example of light causing changes or motion and represent it with a model.