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Natural Indicators—Acids, Bases and the pH Scale—Guided-Inquiry Kit

By: The Flinn Staff

Item #: AP6442

Price: $64.60

In Stock.

The Natural Indicators Chemistry Guided-Inquiry Laboratory Kit allows students to explore the origin of acid–base indicators. Students extract natural indicators and construct a pH color chart to find the pH values of unknown solutions.

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Product Details

Roses are red, violets are blue—or are they? Red roses, as well as many other flowers and fruits, contain natural indicators that are sensitive to acids and bases. The color of a natural acid–base indicator depends on pH. In this activity, the pH scale comes to life in living color as students explore the origin of acid–base indicators in nature. Students extract natural indicators from dried flowers, fruit juices or herbal teas. They then design a procedure to construct a pH color chart for their natural indicator and use the results to analyze the pH values of unknown solutions. Kit includes four natural indicator sources, a set of buffer capsules for the preparation of pH 2–12 standards, four unknowns and synthetic indicators for comparison. Indicator choices include red roses and hibiscus—your chemistry lab will never smell so good! Also includes reproducible student handouts, detailed background information, complete Teacher Notes with sample data and answers to questions and all necessary chemicals and consumable supplies.

Complete for 30 students working in pairs.


Materials Included in Kit: 
Acetic acid solution, 0.1 M, 100 mL
Bromthymol blue solution, 0.04%, 100 mL
Buffer capsules, set of 11 pH values
Methyl orange solution, 0.1%, 100 mL
Natural indicator, hibiscus, 20 g
Natural indicator, rose petals, 20 g
Sodium bicarbonate solution, 0.1 M, 100 mL
Sodium carbonate solution, 0.1 M, 100 mL
Sodium phosphate monobasic solution, 0.1 M, 100 mL
Thymol blue solution, 0.04%, 100 mL
Cranberry apple tea bag, 4
Grape juice, Welch’s©, 100%, 10 oz 
Pipet, Beral-type, thin stem, 75

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Asking questions and defining problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematics and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence

Disciplinary Core Ideas

MS-PS1.B: Chemical Reactions
HS-PS1.B: Chemical Reactions

Crosscutting Concepts

Cause and effect
Scale, proportion, and quantity
Systems and system models

Performance Expectations

HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
HS-PS1-5: Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
HS-PS1-7: Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.