Unit Plan 6 (Grade 5 Science): Chemical Reactions Basics
Grade 5 science unit where students mix substances, observe properties before and after, and use evidence like gas, temperature, and new solids to identify chemical reactions.
Focus: Conduct investigations to observe what happens when two or more substances are mixed, and use evidence from properties before and after to decide whether new substances were formed (chemical reactions) or whether the change is only a physical mixture.
Grade Level: 5
Subject Area: Science (Physical Science • Matter & Chemical Change)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students explore what makes a change a chemical reaction. Using safe household materials (like baking soda, vinegar, yeast, and lemon juice), they compare mixtures that do make new substances (bubbles, temperature change, new odors, new solids) and mixtures that do not (like saltwater). Students observe properties before and after mixing to decide whether a new substance has formed, and they practice using data tables and simple CER writing to justify their conclusions.
Essential Questions
- What evidence can we look for to decide if mixing substances creates a new substance?
- How are chemical reactions different from simple mixtures or solutions?
- Why is it important for scientists and engineers to test and record properties before and after mixing substances?
- How do people use chemical reactions in everyday life (cooking, cleaning, materials, energy)?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Describe and give examples of physical changes (like dissolving or mixing) where no new substances are formed.
- Conduct investigations where two or more substances are mixed, and observe changes in properties (color, temperature, state, gas, formation of a solid).
- Record observations in data tables, comparing before-mixing and after-mixing properties.
- Use patterns in their observations to decide whether a chemical reaction occurred (evidence that new substances formed).
- Construct a simple CER (Claim–Evidence–Reasoning) explaining whether mixing a given pair of substances resulted in new substances.
Standards Alignment — 5th Grade (NGSS-Aligned)
- 5-PS1-4 — Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
- Example: Students mix baking soda and vinegar, observe bubbling and temperature change, and compare this to mixing salt and water (no new substances; just a solution).
Success Criteria — Student Language
- I can name at least one example of mixing where no new substance is formed and one where a new substance is formed.
- I can plan and carry out a mixing investigation and record properties before and after in a data table.
- I can use evidence like gas, color change, temperature change, or new solids to decide if a chemical reaction happened.
- I can explain in writing whether new substances formed and support my claim with specific observations.
- I can use words like chemical reaction, physical change, properties, and evidence correctly.