ACS: Inquiry in Action - Substances Can Mix and React to Form New Substances (Lesson 3.3): Forming a Precipitate
Students combine an Ivory Soap solution with an Epsom salt solution to produce a solid “soap scum” to investigate the questions: What happens when you mix soap with hard water? and Is soap scum different from soap?
Objective
Students will be able to explain that mixing substances can cause a chemical reaction that results in the formation of a new substance. Students will be able to plan and carry out an investigation to compare the amount of bubbles produced by a solid “soap scum” precipitate with the bubbles produced from soap. Students will also be able to explain that different substances react in a characteristic way that can be used to identify a substance.
Key Concepts
- Mixing substances can result in a chemical reaction that produces new substances.
- Two liquids can chemically react to produce a solid.
- Substances have characteristic chemical reactions that can be used to identify a substance.
- Designing a fair test to study chemical reactions requires keeping everything the same except for the one thing you want to know about.
NGSS Alignment
- NGSS 5-PS1-3: Make observations and measurements to identify materials based on their properties.
- NGSS 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Summary
- Students prepare a soap solution by dissolving Ivory soap in water.
- Students also make an Epsom salt solution to simulate hard water.
- Students combine the soap solution with the Epsom salt solution to produce a solid “soap scum” precipitate.
- Students then carry out a bubble test on the solid soap scum and Ivory soap to determine if they are different.
The two main ideas for students to understand from this activity are that mixing substances can result in the formation of a new substance, and that the way different substances react is a characteristic property that can be used to identify a substance.
Evaluation
Download the student activity sheet (PDF) and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.
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Students squeeze a flexible plastic bottle filled with air and another filled with water to investigate the questions: Is an “empty” bottle really empty? and Can you force the molecules of a gas or a liquid to be closer together?
Students compare the dissolving of salt and sugar and then conduct a dissolving test on unknown substances marked A, B, and C to investigate the question: Can substances be identified by how well they dissolve in water?
Students help design a test using baking soda, corn starch, and cream of tartar to investigate the question: Which two of the three ingredients in baking powder react to make it bubble when water is added?
Students combine citric acid with calcium chloride and citric acid with baking soda to investigate the question: What are the similarities and differences between the two reactions? and Do substances react in a characteristic way?
Students add laundry detergent powder (a base) and cream of tartar (an acid) to a red cabbage indicator to investigate the question: What can the color of an indicator tell you about the substances added to it?
Students design and conduct a test using baking soda and baking powder with vinegar to investigate the question: Will baking soda or baking powder produce more gas when vinegar is added?
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Students combine an Ivory Soap solution with an Epsom salt solution to produce a solid “soap scum” to investigate the questions: What happens when you mix soap with hard water? and Is soap scum different from soap?
Objective
Students will be able to explain that mixing substances can cause a chemical reaction that results in the formation of a new substance. Students will be able to plan and carry out an investigation to compare the amount of bubbles produced by a solid “soap scum” precipitate with the bubbles produced from soap. Students will also be able to explain that different substances react in a characteristic way that can be used to identify a substance.
Key Concepts
- Mixing substances can result in a chemical reaction that produces new substances.
- Two liquids can chemically react to produce a solid.
- Substances have characteristic chemical reactions that can be used to identify a substance.
- Designing a fair test to study chemical reactions requires keeping everything the same except for the one thing you want to know about.
NGSS Alignment
- NGSS 5-PS1-3: Make observations and measurements to identify materials based on their properties.
- NGSS 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Summary
- Students prepare a soap solution by dissolving Ivory soap in water.
- Students also make an Epsom salt solution to simulate hard water.
- Students combine the soap solution with the Epsom salt solution to produce a solid “soap scum” precipitate.
- Students then carry out a bubble test on the solid soap scum and Ivory soap to determine if they are different.
The two main ideas for students to understand from this activity are that mixing substances can result in the formation of a new substance, and that the way different substances react is a characteristic property that can be used to identify a substance.
Evaluation
Download the student activity sheet (PDF) and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.
Back to Fifth Grade Lessons
Guided instructions, lesson plans, classroom activities, video demonstrations, and activity books.
Students squeeze a flexible plastic bottle filled with air and another filled with water to investigate the questions: Is an “empty” bottle really empty? and Can you force the molecules of a gas or a liquid to be closer together?
Students compare the dissolving of salt and sugar and then conduct a dissolving test on unknown substances marked A, B, and C to investigate the question: Can substances be identified by how well they dissolve in water?
Students help design a test using baking soda, corn starch, and cream of tartar to investigate the question: Which two of the three ingredients in baking powder react to make it bubble when water is added?
Students combine citric acid with calcium chloride and citric acid with baking soda to investigate the question: What are the similarities and differences between the two reactions? and Do substances react in a characteristic way?
Students add laundry detergent powder (a base) and cream of tartar (an acid) to a red cabbage indicator to investigate the question: What can the color of an indicator tell you about the substances added to it?
Students design and conduct a test using baking soda and baking powder with vinegar to investigate the question: Will baking soda or baking powder produce more gas when vinegar is added?
What are you looking for?
Organization
Website URL
Type of Resource
PDF File
Video (Instructional)
