Elephant Toothpaste! Did We Make Something New?

Day 1: Exploring Changes & Setting Up the Mystery

Objective: Students will distinguish between physical and chemical changes and make initial observations of the Elephant Toothpaste experiment.

(1) Engage (20 minutes): What Happens When Things Change?

• Warm-up: Show examples of changes:
  • Physical: Ripping paper, melting ice, mixing sand and water. Ask: "Did we make something new here, or just change how it looks?" (No new stuff).
  • Chemical: Burning paper (ash, smoke), baking cookies (new smell, taste, texture). Ask: "Did we make something new here?" (Yes, new stuff!)
• Vocabulary: Introduce "physical change" (looks different, no new stuff) and "chemical change" (new stuff is made).
• Essential Question: Introduce: "When we mix things like hydrogen peroxide and yeast, do they just mix together, or do they make completely new stuff?" Explain this is our big mystery to solve!

(2) Explore (30 minutes): First Look at Elephant Toothpaste

• Materials Introduction & Safety: Show all materials. Emphasize safety goggles MUST be worn during the experiment. Explain the foam is soapy water and not for eating.
• Teacher Demonstration: Perform a careful demonstration of the Elephant Toothpaste reaction (using 3% peroxide).
  • Ask students to describe what they see, hear, and feel (carefully, bottle might be warm).
  • "What do you think is happening here?"
• Initial Group Investigation: Distribute materials to student groups (except yeast mixture). Guide them to pour peroxide and soap into their bottles.
• Yeast Activation: Guide students to mix yeast with warm water in a separate cup.
• The Reaction! Have groups carefully pour the yeast mixture into their bottles and observe.
• Record Observations: Students draw and write their initial observations in their science notebooks: "What did you see? What did you hear? What did you feel?" (Focus on the foam, warmth, bubbling).

(3) Explain (20 minutes): Discussing Observations & Evidence

• Class Share Out: Facilitate a discussion. "What did everyone observe during the reaction?" List their observations on the board (e.g., "lots of foam," "bottle got warm," "it pushed out fast").
• Connecting to Changes: "Based on what we saw, do you think we just mixed things together, or did something new get made?" Discuss common clues for new substances:
  • New bubbles/gas (that wasn't there before).
  • Temperature change (gets hot or cold).
  • New color (not just mixing paints).
  • New smell.
• Introducing the Performance Task: Explain the "Chemical Detective" Lab Report and "Evidence Board" they'll create to share their findings.

(4) Elaborate (10 minutes): Planning for More Clues

• What else could we try? "If we want to be super detectives, what else could we try to see more clues about new substances?" (Guide towards testing different amounts of yeast, or different water temperatures for the yeast, or even milk vs. water as a comparison).
• Homework: Students brainstorm one idea for a different "test" their team could try tomorrow to get more evidence.

Day 2: Deeper Investigations & Gathering Evidence

Objective: Students will conduct comparative investigations, collect specific evidence, and begin to interpret whether new substances were formed.

(1) Engage (10 minutes): Review & Test Plans

• Share Test Ideas: Have each group briefly share the variation they want to test (e.g., "We'll try more yeast today," "We'll use colder water for the yeast").
• Review Lab Report Sections: Quickly review the sections of their "Chemical Detective" Lab Report where they'll record their new observations.

(2) Explore (45 minutes): Conducting Comparative Investigations

• Conducting Trials: Groups conduct their chosen comparative investigation. They should run their original experiment again as a control, and then run their modified experiment.
• Detailed Observation & Data Collection: Students record observations for each trial in their science notebooks/lab reports. Focus on:
  • Trial 1 (Original): What was used, what happened, clues.
  • Trial 2 (Changed): What was changed, what happened, clues.
  • Compare the two: "Did it make more foam? Did it get hotter or less hot?"
• Teacher Facilitation: Circulate, ensure safety, prompt detailed observations, and ask: "What evidence are you collecting that tells you if something new is being made?"

(3) Explain (25 minutes): Analyzing Clues & Forming Conclusions

• Group Discussion: Teams discuss their observations and compare their two trials. "What clues did you find? Did changing anything affect how much foam there was?"
• Evidence Review: Guide them to look at their collected "clues" (foam/gas, warmth, etc.). "Do these clues point to a physical change (just mixing) or a chemical change (making new stuff)?"
• Preliminary Conclusion: Each group forms a preliminary conclusion about whether new substances were formed, based on their evidence.
• Introducing the Evidence Board: Explain they will create a visual "Evidence Board" to share their findings.

(4) Elaborate (10 minutes): Planning the Evidence Board

• Evidence Board Sections: Discuss what goes on the board:
  • Their question
  • What they did (pictures/steps)
  • What they saw (drawings of the foam, notes about warmth, bubbles)
  • Their conclusion (Did new stuff get made? Why or why not?)
• Homework: Students begin sketching ideas for their Evidence Board, thinking about how to show their observations clearly.

Day 3: "Chemical Detective" Lab Reports & Evidence Boards

Objective: Students will finalize their lab reports and Evidence Boards, presenting their findings and conclusions about physical vs. chemical changes.

(1) Engage (10 minutes): Review & Materials

• Review Task: Remind students of their goal: to complete their Lab Report and Evidence Board explaining whether new substances were formed.
• Materials for Board: Provide large paper/poster board, markers, colored pencils, glue sticks/tape.

(2) Explore & Explain (45 minutes): Report & Board Creation

• Lab Report Completion: Groups finish writing their "Chemical Detective" Lab Reports, using their notes and observations as evidence.
• Evidence Board Creation: Groups create their visual "Evidence Boards." They can draw pictures, write key observations, and clearly state their conclusion (e.g., "We think new stuff WAS made because...").
• Teacher Support: Circulate, provide writing support, help with organization, and prompt students to connect their observations directly to the idea of new substances being formed.

(3) Elaborate & Evaluate (30 minutes): Presentations & Class Discussion

• Group Presentations: Each team presents their "Chemical Detective" Lab Report and Evidence Board to the class. They should explain their question, what they did, what they saw, and their conclusion.
• Peer Questions: Encourage classmates to ask questions about the evidence presented.
• Class Discussion: Facilitate a whole-class discussion, synthesizing the findings. "What did most groups conclude? What were the strongest pieces of evidence that new stuff was made?" Reinforce that the gas and heat are strong clues that a chemical change (making new substances) happened.

Differentiate: Limited observations: Focus on 2-3 key observations (e.g., foam, warmth) rather than all categories. Pre-selected experimental variations: Assign a simpler variation (e.g., just change yeast amount).

Extend: "Challenge" variable: Encourage them to research and test a less obvious variable (e.g., using different water temperatures for the yeast, or even trying a different type of soap). Predicting outcomes: Ask them to predict the outcome of their chosen variable before they conduct the experiment.

Use the student performance task linked in the resources tab to assess student learning outcomes.