1. Nature of science Review

Key Vocabulary

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Signs of a Chemical Reaction

Scientists look for evidence such as:

• Gas formation (bubbles)
• Temperature change
• Color change
• Formation of a new substance

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Understanding the Investigation

Amal is trying to design an egg incubator that keeps snake eggs at the correct temperature.

Design Criteria

The incubator must:

• Be portable
• Be lightweight
• Be inexpensive
• Use minimal chemicals
• Maintain temperature 28°C–32°C
• Protect the egg from impact

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Understanding Data Tables

Scientists analyze data tables to look for:

• Patterns
• Temperature changes
• Effects of different amounts of chemicals
• Evidence of chemical reactions

When reading tables, ask:

• What changed between the trials?
• What stayed the same?
• What results were recorded?

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FAST Test Tips

✓ Look for evidence in the experiment description
✓ Words like bubbles or gas indicate chemical reactions
✓ Temperature changes can indicate energy released or absorbed
✓ When gas escapes from an open container, mass may appear to decrease
✓ Compare results with the design criteria

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Peer Tutoring Script

Student Leader Instructions

1. Read the investigation scenario together.

2. Discuss the problem Amal is trying to solve.

3. Look carefully at the data tables.

4. Ask brainstorming questions before choosing an answer.

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Introduction Discussion (2 minutes)

Student leader asks:

• What problem is Amal trying to solve?
• Why must the incubator stay within a specific temperature range?
• What materials are being tested in the investigation?

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Question 1 Discussion

Brainstorming Questions

Student leader asks:

• What did Amal observe during the second test?
• What happens when bubbles form in a chemical experiment?
• What might the bubbles represent?

Students discuss how scientists identify evidence of chemical reactions.

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Question 2 Discussion

Brainstorming Questions

Student leader asks:

• What was the total mass at the beginning of the experiment?
• What was the total mass after five minutes?
• What happened during the reaction that might affect the mass measurement?
• Could something have left the container?

Students discuss changes in measured mass during reactions.

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Question 3 Discussion

Brainstorming Questions

Student leader asks:

• What does the law of conservation of mass say about matter?
• When a chemical reaction happens, what happens to the atoms?
• Do atoms disappear, or do they rearrange?

Students examine how molecular models represent chemical reactions.

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Question 4 Discussion

Brainstorming Questions

Student leader asks:

• What temperature range must the incubator maintain?
• Which trials produced temperatures inside the required range?
• Which trials produced temperatures outside the required range?

Students analyze Table 1 and Table 2 data.

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Question 5 Discussion

Brainstorming Questions

Student leader asks:

• What temperature range can the snake eggs survive?
• What does “high end of the range” mean?
• How did the amount of calcium chloride affect temperature in the experiment?

Students analyze patterns in the data tables.

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Question 6 Discussion

Brainstorming Questions

Student leader asks:

• What is the purpose of foam and bubble wrap?
• How might insulation affect temperature?
• How might the box affect protection of the eggs?

Students discuss engineering improvements to the design.

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Reflection Questions for the Group

Student leader asks:

• What variables changed in Amal’s experiments?
• What evidence showed a chemical reaction occurred?
• Why do scientists analyze data tables carefully before making conclusions?
• How did Amal use experiments to improve his design?