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Mystery Powders

Container of flour

Container of flour (Karolina Grabowska, Pixabay)

Container of flour

Container of flour (Karolina Grabowska, Pixabay)

Format
Subjects
Let's Talk Science

How does this align with my curriculum?

Students investigate the properties of a variety of everyday solids (powders) and liquids to determine the identity of an unknown solid (mystery powder).

Overview

Activities Timing Student grouping Description
Minds-On: Mystery Powder Fair Test 15 minutes Large group Teacher introduces the mystery powder and demonstrates how to do a fair test (controlled experiment).
Action: Exploring Powders 40-50 minutes Small group Students use a fair test on a variety of white powders to determine which one is the mystery powder.
Consolidation: Polling Results 20-30 minutes Independent and large group Students determine if the observed changes were physical or chemical and learn the identity of the mystery powder.

This lesson can be done over a few days.

Students will:

  • Explore the properties of different solids and liquids
  • Understand some of the possible outcomes when a solid and a liquid are combined
  • Demonstrate an understanding of physical and chemical changes
  • Follow established health and safety procedures during a scientific investigation
  • Communicate finding in a variety of formats

Learning Goals

Students will:

  • Explore the properties of different solids and liquids
  • Understand some of the possible outcomes when a solid and a liquid are combined
  • Demonstrate an understanding of physical and chemical changes
  • Follow established health and safety procedures during a scientific investigation
  • Communicate finding in a variety of formats

Students can:

  • Identify and describe the properties of different solids and liquids
  • Predict and observe what happens when a solid and a liquid property are mixed together
  • Accurately identify examples of physical and chemical changes after a set solids are mixed with a liquid
  • Safety measure, mix and observe a variety of solids and liquids
  • Effectively communicate their understanding of physical and chemical changes and scientific processes in written products and oral discussions

Success Criteria

Students can:

  • Identify and describe the properties of different solids and liquids
  • Predict and observe what happens when a solid and a liquid property are mixed together
  • Accurately identify examples of physical and chemical changes after a set solids are mixed with a liquid
  • Safety measure, mix and observe a variety of solids and liquids
  • Effectively communicate their understanding of physical and chemical changes and scientific processes in written products and oral discussions
Assessment opporunties icon

This icon indicates potential assessment opportunities.

Observations 

  • Observe and record anecdotally students’ understanding of the properties of solids and their use of appropriate vocabulary to describe the characteristics of solids and liquids (Minds-on, Action).
  • Observe and record anecdotally students’ understanding of physical and chemical changes (Consolidation).

Conversations

  • Have conversations with students as they do the fair testing process. Document student handling of materials and equipment (Action).

Products

  • Students could complete and submit the Powder Predict and Observe Chart  (Action)
  • Students could complete and submit the Physical or Chemical Change Identification Chart reproducible (Consolidation).

Evidence of Student Learning

Assessment opporunties icon

This icon indicates potential assessment opportunities.

Observations 

  • Observe and record anecdotally students’ understanding of the properties of solids and their use of appropriate vocabulary to describe the characteristics of solids and liquids (Minds-on, Action).
  • Observe and record anecdotally students’ understanding of physical and chemical changes (Consolidation).

Conversations

  • Have conversations with students as they do the fair testing process. Document student handling of materials and equipment (Action).

Products

  • Students could complete and submit the Powder Predict and Observe Chart  (Action)
  • Students could complete and submit the Physical or Chemical Change Identification Chart reproducible (Consolidation).

Students will:

  • Explore the properties of different solids and liquids
  • Understand some of the possible outcomes when a solid and a liquid are combined
  • Demonstrate an understanding of physical and chemical changes
  • Follow established health and safety procedures during a scientific investigation
  • Communicate finding in a variety of formats

Learning Goals

Students will:

  • Explore the properties of different solids and liquids
  • Understand some of the possible outcomes when a solid and a liquid are combined
  • Demonstrate an understanding of physical and chemical changes
  • Follow established health and safety procedures during a scientific investigation
  • Communicate finding in a variety of formats

Students can:

  • Identify and describe the properties of different solids and liquids
  • Predict and observe what happens when a solid and a liquid property are mixed together
  • Accurately identify examples of physical and chemical changes after a set solids are mixed with a liquid
  • Safety measure, mix and observe a variety of solids and liquids
  • Effectively communicate their understanding of physical and chemical changes and scientific processes in written products and oral discussions

Success Criteria

Students can:

  • Identify and describe the properties of different solids and liquids
  • Predict and observe what happens when a solid and a liquid property are mixed together
  • Accurately identify examples of physical and chemical changes after a set solids are mixed with a liquid
  • Safety measure, mix and observe a variety of solids and liquids
  • Effectively communicate their understanding of physical and chemical changes and scientific processes in written products and oral discussions
Assessment opporunties icon

This icon indicates potential assessment opportunities.

Observations 

  • Observe and record anecdotally students’ understanding of the properties of solids and their use of appropriate vocabulary to describe the characteristics of solids and liquids (Minds-on, Action).
  • Observe and record anecdotally students’ understanding of physical and chemical changes (Consolidation).

Conversations

  • Have conversations with students as they do the fair testing process. Document student handling of materials and equipment (Action).

Products

  • Students could complete and submit the Powder Predict and Observe Chart  (Action)
  • Students could complete and submit the Physical or Chemical Change Identification Chart reproducible (Consolidation).

Evidence of Student Learning

Assessment opporunties icon

This icon indicates potential assessment opportunities.

Observations 

  • Observe and record anecdotally students’ understanding of the properties of solids and their use of appropriate vocabulary to describe the characteristics of solids and liquids (Minds-on, Action).
  • Observe and record anecdotally students’ understanding of physical and chemical changes (Consolidation).

Conversations

  • Have conversations with students as they do the fair testing process. Document student handling of materials and equipment (Action).

Products

  • Students could complete and submit the Powder Predict and Observe Chart  (Action)
  • Students could complete and submit the Physical or Chemical Change Identification Chart reproducible (Consolidation).

 

Materials and Preparation 

Material/Technology/Setting Quantity
  • A variety of food-safe white ‘powders’ (e.g., flour, icing sugar, granulated sugar, cornstarch, baking soda or baking powder, powdered milk, etc.)*
  • Mystery powder (baking soda or baking powder)
  • ½ cup white vinegar (in cup or sealed container like a medicine bottle)
Vinegar, icing sugar, flour, baking soda, baking powder, and granulated sugar
Potential materials (©2022 Let’s Talk Science).
Image - Text Version

Shown is a colour photograph of a collection of packages on a table.

Most of the packages contain white powder. There is a box of baking soda, a jar of baking powder, and bags of sugar, flour, and icing sugar. In the background is a large, clear plastic bottle with a green lid.

  • Resealable bags (one for each powder)
  • Permanent marker (to label each powder)
  • Masking tape
  • Hand lenses/magnifying glasses
  • Small plastic containers (paint palettes or trays, plates, divided fast food containers, cups, muffin tray, yogurt containers, other recycled containers, etc.) 
Divided tray
Divided plastic food tray (Source: WichienTep via iStockphoto).
Image - Text Version

Shown is a colour photograph of a tray with four sections, on a white background. 

The tray is brown plastic, and rectangular. It is divided into four smaller, rectangular sections.

  •  Measuring spoons: 1 tsp for the powders and 1 tsp for the liquids
  • Objects for stirring (wooden or plastic spoons, stir sticks, etc.)
  • Mystery Powder Predict and Observe Chart reproducible [Google doc] [Word doc] [PDF]
  • Mystery Powder Fair Test Task Card reproducible [Google doc] [Word doc] [PDF] (optional)
  • Physical or Chemical Change Identification Chart reproducible [Google doc] [Word doc] [PDF]

*check for allergies before using any of the materials. Wheat flour could be substituted for a gluten-free flour such as rice flour, buckwheat flour, coconut flour, oat flour, etc. 

Enough for small groups of 4-5 students
  • Baking soda or baking powder in a clear plastic container or glass jar with lid
  • 1 tsp measuring spoon
  • 1 tsp white vinegar
  • Small plastic container
  • Whiteboard/blackboard or chart paper and marker
  • Physical and Chemical Changes interactive presentation [html] [Google slides] [pptx] [PDF].
For teacher use

 

Materials

Material/Technology/Setting Quantity
  • A variety of food-safe white ‘powders’ (e.g., flour, icing sugar, granulated sugar, cornstarch, baking soda or baking powder, powdered milk, etc.)*
  • Mystery powder (baking soda or baking powder)
  • ½ cup white vinegar (in cup or sealed container like a medicine bottle)
Vinegar, icing sugar, flour, baking soda, baking powder, and granulated sugar
Potential materials (©2022 Let’s Talk Science).
Image - Text Version

Shown is a colour photograph of a collection of packages on a table.

Most of the packages contain white powder. There is a box of baking soda, a jar of baking powder, and bags of sugar, flour, and icing sugar. In the background is a large, clear plastic bottle with a green lid.

  • Resealable bags (one for each powder)
  • Permanent marker (to label each powder)
  • Masking tape
  • Hand lenses/magnifying glasses
  • Small plastic containers (paint palettes or trays, plates, divided fast food containers, cups, muffin tray, yogurt containers, other recycled containers, etc.) 
Divided tray
Divided plastic food tray (Source: WichienTep via iStockphoto).
Image - Text Version

Shown is a colour photograph of a tray with four sections, on a white background. 

The tray is brown plastic, and rectangular. It is divided into four smaller, rectangular sections.

  •  Measuring spoons: 1 tsp for the powders and 1 tsp for the liquids
  • Objects for stirring (wooden or plastic spoons, stir sticks, etc.)
  • Mystery Powder Predict and Observe Chart reproducible [Google doc] [Word doc] [PDF]
  • Mystery Powder Fair Test Task Card reproducible [Google doc] [Word doc] [PDF] (optional)
  • Physical or Chemical Change Identification Chart reproducible [Google doc] [Word doc] [PDF]

*check for allergies before using any of the materials. Wheat flour could be substituted for a gluten-free flour such as rice flour, buckwheat flour, coconut flour, oat flour, etc. 

Enough for small groups of 4-5 students
  • Baking soda or baking powder in a clear plastic container or glass jar with lid
  • 1 tsp measuring spoon
  • 1 tsp white vinegar
  • Small plastic container
  • Whiteboard/blackboard or chart paper and marker
  • Physical and Chemical Changes interactive presentation [html] [Google slides] [pptx] [PDF].
For teacher use

 

  • Choose 4-5 different powders for students to test. For each group, put each of the powders into a resealable bag and label the name of the powder on the bag with a permanent marker.
  • Pour the vinegar into small containers with lids. Label the contents of each with masking tape and permanent marker.
  • Put some baking soda or baking powder (the amount is not important) into a clear container.
  • Bring the jar of baking soda  or baking powder, small plastic container, measuring spoons, and vinegar with you to the initial discussion.
  • Print out enough Powder Predict and Observe ChartPhysical or Chemical Change Identification Chart and Mystery Powder Fair Test Task Card reproducibles for each group.

Note: the Mystery Powder Fair Test Task Card does not need to be handed out to each group, it could be projected on a screen for students to view while doing the experiment. 

Preparation

  • Choose 4-5 different powders for students to test. For each group, put each of the powders into a resealable bag and label the name of the powder on the bag with a permanent marker.
  • Pour the vinegar into small containers with lids. Label the contents of each with masking tape and permanent marker.
  • Put some baking soda or baking powder (the amount is not important) into a clear container.
  • Bring the jar of baking soda  or baking powder, small plastic container, measuring spoons, and vinegar with you to the initial discussion.
  • Print out enough Powder Predict and Observe ChartPhysical or Chemical Change Identification Chart and Mystery Powder Fair Test Task Card reproducibles for each group.

Note: the Mystery Powder Fair Test Task Card does not need to be handed out to each group, it could be projected on a screen for students to view while doing the experiment. 

  • A basic understanding of the properties of solids and liquids
  • A basic understanding of physical and chemical changes.
  • Observation skills.
  • Practice doing fair tests, or controlled experiments, is an asset but not essential.
  • It is highly recommended that students participate in the Exploring Physical and Chemical Changes lesson before doing this lesson.

Student Prior Knowledge and Skills

  • A basic understanding of the properties of solids and liquids
  • A basic understanding of physical and chemical changes.
  • Observation skills.
  • Practice doing fair tests, or controlled experiments, is an asset but not essential.
  • It is highly recommended that students participate in the Exploring Physical and Chemical Changes lesson before doing this lesson.
Material/Technology/Setting Quantity
  • A variety of food-safe white ‘powders’ (e.g., flour, icing sugar, granulated sugar, cornstarch, baking soda or baking powder, powdered milk, etc.)*
  • Mystery powder (baking soda or baking powder)
  • ½ cup white vinegar (in cup or sealed container like a medicine bottle)
Vinegar, icing sugar, flour, baking soda, baking powder, and granulated sugar
Potential materials (©2022 Let’s Talk Science).
Image - Text Version

Shown is a colour photograph of a collection of packages on a table.

Most of the packages contain white powder. There is a box of baking soda, a jar of baking powder, and bags of sugar, flour, and icing sugar. In the background is a large, clear plastic bottle with a green lid.

  • Resealable bags (one for each powder)
  • Permanent marker (to label each powder)
  • Masking tape
  • Hand lenses/magnifying glasses
  • Small plastic containers (paint palettes or trays, plates, divided fast food containers, cups, muffin tray, yogurt containers, other recycled containers, etc.) 
Divided tray
Divided plastic food tray (Source: WichienTep via iStockphoto).
Image - Text Version

Shown is a colour photograph of a tray with four sections, on a white background. 

The tray is brown plastic, and rectangular. It is divided into four smaller, rectangular sections.

  •  Measuring spoons: 1 tsp for the powders and 1 tsp for the liquids
  • Objects for stirring (wooden or plastic spoons, stir sticks, etc.)
  • Mystery Powder Predict and Observe Chart reproducible [Google doc] [Word doc] [PDF]
  • Mystery Powder Fair Test Task Card reproducible [Google doc] [Word doc] [PDF] (optional)
  • Physical or Chemical Change Identification Chart reproducible [Google doc] [Word doc] [PDF]

*check for allergies before using any of the materials. Wheat flour could be substituted for a gluten-free flour such as rice flour, buckwheat flour, coconut flour, oat flour, etc. 

Enough for small groups of 4-5 students
  • Baking soda or baking powder in a clear plastic container or glass jar with lid
  • 1 tsp measuring spoon
  • 1 tsp white vinegar
  • Small plastic container
  • Whiteboard/blackboard or chart paper and marker
  • Physical and Chemical Changes interactive presentation [html] [Google slides] [pptx] [PDF].
For teacher use

 

Materials

Material/Technology/Setting Quantity
  • A variety of food-safe white ‘powders’ (e.g., flour, icing sugar, granulated sugar, cornstarch, baking soda or baking powder, powdered milk, etc.)*
  • Mystery powder (baking soda or baking powder)
  • ½ cup white vinegar (in cup or sealed container like a medicine bottle)
Vinegar, icing sugar, flour, baking soda, baking powder, and granulated sugar
Potential materials (©2022 Let’s Talk Science).
Image - Text Version

Shown is a colour photograph of a collection of packages on a table.

Most of the packages contain white powder. There is a box of baking soda, a jar of baking powder, and bags of sugar, flour, and icing sugar. In the background is a large, clear plastic bottle with a green lid.

  • Resealable bags (one for each powder)
  • Permanent marker (to label each powder)
  • Masking tape
  • Hand lenses/magnifying glasses
  • Small plastic containers (paint palettes or trays, plates, divided fast food containers, cups, muffin tray, yogurt containers, other recycled containers, etc.) 
Divided tray
Divided plastic food tray (Source: WichienTep via iStockphoto).
Image - Text Version

Shown is a colour photograph of a tray with four sections, on a white background. 

The tray is brown plastic, and rectangular. It is divided into four smaller, rectangular sections.

  •  Measuring spoons: 1 tsp for the powders and 1 tsp for the liquids
  • Objects for stirring (wooden or plastic spoons, stir sticks, etc.)
  • Mystery Powder Predict and Observe Chart reproducible [Google doc] [Word doc] [PDF]
  • Mystery Powder Fair Test Task Card reproducible [Google doc] [Word doc] [PDF] (optional)
  • Physical or Chemical Change Identification Chart reproducible [Google doc] [Word doc] [PDF]

*check for allergies before using any of the materials. Wheat flour could be substituted for a gluten-free flour such as rice flour, buckwheat flour, coconut flour, oat flour, etc. 

Enough for small groups of 4-5 students
  • Baking soda or baking powder in a clear plastic container or glass jar with lid
  • 1 tsp measuring spoon
  • 1 tsp white vinegar
  • Small plastic container
  • Whiteboard/blackboard or chart paper and marker
  • Physical and Chemical Changes interactive presentation [html] [Google slides] [pptx] [PDF].
For teacher use

 

  • Choose 4-5 different powders for students to test. For each group, put each of the powders into a resealable bag and label the name of the powder on the bag with a permanent marker.
  • Pour the vinegar into small containers with lids. Label the contents of each with masking tape and permanent marker.
  • Put some baking soda or baking powder (the amount is not important) into a clear container.
  • Bring the jar of baking soda  or baking powder, small plastic container, measuring spoons, and vinegar with you to the initial discussion.
  • Print out enough Powder Predict and Observe ChartPhysical or Chemical Change Identification Chart and Mystery Powder Fair Test Task Card reproducibles for each group.

Note: the Mystery Powder Fair Test Task Card does not need to be handed out to each group, it could be projected on a screen for students to view while doing the experiment. 

Preparation

  • Choose 4-5 different powders for students to test. For each group, put each of the powders into a resealable bag and label the name of the powder on the bag with a permanent marker.
  • Pour the vinegar into small containers with lids. Label the contents of each with masking tape and permanent marker.
  • Put some baking soda or baking powder (the amount is not important) into a clear container.
  • Bring the jar of baking soda  or baking powder, small plastic container, measuring spoons, and vinegar with you to the initial discussion.
  • Print out enough Powder Predict and Observe ChartPhysical or Chemical Change Identification Chart and Mystery Powder Fair Test Task Card reproducibles for each group.

Note: the Mystery Powder Fair Test Task Card does not need to be handed out to each group, it could be projected on a screen for students to view while doing the experiment. 

  • A basic understanding of the properties of solids and liquids
  • A basic understanding of physical and chemical changes.
  • Observation skills.
  • Practice doing fair tests, or controlled experiments, is an asset but not essential.
  • It is highly recommended that students participate in the Exploring Physical and Chemical Changes lesson before doing this lesson.

Student Prior Knowledge and Skills

  • A basic understanding of the properties of solids and liquids
  • A basic understanding of physical and chemical changes.
  • Observation skills.
  • Practice doing fair tests, or controlled experiments, is an asset but not essential.
  • It is highly recommended that students participate in the Exploring Physical and Chemical Changes lesson before doing this lesson.

 

Teaching and Learning Activities 

Assessment opporunties icon

This icon indicates potential assessment opportunities.

Minds-On: Mystery Powder Fair Test 15 min. 

Instructions Teaching Tips

Show students the jar filled with the mystery powder (baking soda or powder). Tell them that you are unsure of what this powder is and you need their help to figure it out.

Ask students to suggest ways to determine what kind of powder it is. Students may make suggestions such as feel it, taste it, smell it, or look at it up close. Pass the jar around so that students can take a closer look at the powder.

Remind students that when they are using their senses to gain information, they are using the skill of observation.

Have students make observations of the powder and record them on the board or a sheet of paper under the headline “Observations”.

Ask students to predict what they think will happen if vinegar is added to the powder. Make notes of students' predictions on the board or a sheet of paper under the headline “Predictions”.

Line drawing of a chalkboard with "abc" written on it

Language

Consider creating a word wall of terminology that students will encounter over the course of this lesson such as powder, grainy, coarse, smooth, matte, shiny, rough, bubbles, gas, independent variable, controlled variable, dependent variable, etc.

Line drawing of an exclamation mark inside of a triangle

Safety

Remind students to never put anything in their mouths, to smell, or to touch, unless told it is safe to do so by a trusted adult. In science we do not use our senses of taste, touch or smell to make observations unless we know it is safe to do so.

line drawing of a lightbulb

Idea

If it is conducive to your classroom you could have students use their sense of taste if they wish, provided there are no allergies to any of the powders. All of these suggested powders from the materials are safe for ingesting.

Explain or review the concept of a fair test (also known as a controlled experiment) with students.

In a fair test, only one thing (the independent variable) is changed at a time. Everything else (the controlled variables) are kept the same. That way, only the independent variable leads to the results (dependent variable). Explain that in the test you are doing, and in the testing they will do, only the powder will be changed. The volume of liquids and solids, the type of liquid, the length of time stirring, will remain the same for each.

Carefully measure out 1 tsp of the mystery powder into a small cup or dish. Then measure and add 1 tsp of vinegar to the powder. Have students closely observe as you mix the two together.

Ask students to describe what they have observed and write these new observations on the board or a sheet of paper under the heading “Results

Now tell students that they will be conducting their own fair test with the powders. Explain to students they are matching up the physical properties and chemical reaction of the known powders to the "mystery" one. It is up to them to see if they can discover which of their powders is the mystery powder in the jar.

 

 

Action: Exploring Powders 40-50 min.

Instructions Teaching Tips

Arrange students in groups of 4-5.

Provide each group with 1 bag of each of the labeled white powders and with the Mystery Powder Predict and Observe Chart reproducible [Google doc] [Word doc] [PDF].

""
Mystery Powder Predict and Observe Chart (©2022 Let’s Talk Science).

Note: Modify the chart to reflect the powders that the class will be testing.

Have the students delegate the tasks in their group (e.g., one person is the note taker, another person can measure out the vinegar, another can add the vinegar to the powder, etc.). Students can take turns doing these tasks.

Explain the instructions to students. You could do this by providing each group with the Mystery Powder Fair Test Task Card reproducible [Google doc] [Word doc] [PDF] or projecting the page digitally on a screen.

""
Mystery Powder Fair Test Task Card (©2022 Let’s Talk Science).

Review each of the steps with students to ensure that they understand each step. 

Note: Below are some examples of powders mixed with vinegar for your reference.

Powders mixed with vinegar
Baking powder, baking soda, flour and icing sugar mixed with vinegar (©2022 Let’s Talk Science).
Image - Text Version

Shown are four colour photographs of four cups with white powder and liquid mixed together.

The camera looks straight down on a a black silicone muffin cup in each photograph. They are arranged in a grid, and the powder and liquid in each is labelled underneath.

On the top left, the first cup is overflowing with bubbles. Clumps of a white substance are visible in between them. This is labelled "Baking powder and white vinegar."

To the right, the second has fewer bubbles than the first, in a thick, white liquid at the bottom of the cup. This is labelled "Baking soda and vinegar."

On the bottom left, the third cup contains cream coloured sludge with tiny bubbles. Clumps of wet powder are stuck to the sides of the cup. This is labelled "Flour and vinegar."

The bottom right cup has thin, translucent grey liquid with no bubbles. This is labelled "Icing sugar and vinegar."

Assessment opporunties icon

Observe students’ interactions with the materials and the fair testing process, and document observations, including discussions and questions raised, to determine the direction of future learning.

Facilitate discussion with students about their findings and how the information gathered can be used to determine what is in the “mystery powder.”

Nature of Science

Scientists do not work alone. They work on teams where different members bring different skills and abilities to the task they are working on.

Line drawing of a chalkboard with "abc" written on it

Language

Review what a prediction is to ensure students understand the concept before beginning the activity. Suggested prompts can include:

  • “What do you think a prediction is?”
  • “How do we make predictions?”
  • “Why is it important to make a prediction?”
  • “When do we make predictions?”
Line drawing of an exclamation mark inside of a triangle

Safety

Remind students to never put anything in their mouths unless told it is safe to do so by a trusted adult.

Line drawing of a computer monitor with a play button

Images and Videos

Adapt the Mystery Powder Predict and Observe Chart reproducible to include the powders that the students will be using.

Nature of Science

Students use the Computational Thinking Skills of pattern recognition and logical thinking as they work to determine how each powder is like or unlike the mystery powder.

 

 

Consolidation: Polling Results 10 min.

Instructions Teaching Tips

Conduct a poll to have students vote on which powder they think is the mystery powder. You could do this by a show of hands, using a digital program (e.g., Poll EverywherePlickers, etc.) or on chart paper.

At the end look at what the most common prediction was and ask the class if they agree. Ask students to explain their reasoning. Reveal to them what the mystery powder was (baking soda or baking powder).

line drawing of a lightbulb

Idea

For a no tech option, have the powder names written on the board and give students a sticky note, chalk or marker and leave a mark under the powder they want to vote for.

Nature of Science

This sharing of results and conclusions is analogous to what scientists do. Sometimes results are shared with small groups, at conferences, etc. Feedback could send them back to the lab to do more research or might help them clarify their thinking. The final step is usually that results are published in a magazine for more scientists to learn from the work they did.

 

The final task will draw on students' prior knowledge of physical and chemical changes. If students are familiar with the topic, go on to the last step of these instructions.

If students are not familiar with the topic of physical and chemical changes you could activate their prior knowledge by asking discussion questions and recording student answers or showing them the Physical and Chemical Changes interactive presentation [html] [Google slides] [pptx] [PDF].

In addition, seeding some photo examples might be helpful for students.

Signs of chemical reactions
Signs of chemical reactions (Let’s Talk Science using images from iStockphoto).
Image - Text Version

Shown are five colour photographs of chemical reactions, arranged and labelled on a blue background.

The title, "Signs of Chemical Reactions" is in black letters across the top of the image. The photographs are arranged in two rows below.

On the top left is a photograph of a hand squeezing juice from a lemon onto a pile of white powder, which is bubbling. The is labelled "Gas is Produced."

To the right is a photograph of logs burning. This is labelled "Temperature Changes."

The last in the row is a photograph of nails on wood. The pile on the right is shiny, silver coloured metal. The pile on the left is red and rusty. This is labelled "Colour Changes."

On the bottom row, the left photograph is of an insect with a back end that glows green. This illuminates the leaf where it sits. This is labelled "Light is Given Off."

The final photograph shows three glass bottles with stoppers. The bottom of each is filled with a different liquid. The top and sides of each bottle are fogged. This is labelled "Precipitate is Produced."

Assessment opporunties icon

Have conversations with students about the differences between physical and chemical changes.

Line drawing of speech bubbles

Discussions

Discussion prompts can include:

  • “How do we know the difference between a physical change or a chemical change?”
  • “What causes physical changes?”
  • "What causes chemical changes?"

After students have reviewed information relating to physical and chemical changes, you could have them complete the Physical or Chemical Change Identification Chart reproducible [Google doc] [Word doc] [PDF] either individually, in small groups, or as a class.

""
Physical or Chemical Change Identification Chart reproducible (©2022 Let’s Talk Science).

Note: Modify the chart to reflect the powders that the class will be testing.

Assessment opporunties icon

Students could hand in the completed reproducible which could be used as an assessment of learning.

For reference:

  • Vinegar + granulated sugar = physical change (sugar does not dissolve completely in vinegar which is a weak acid. Vinegar is mostly water and sugar does dissolve in water.)
  • Vinegar + icing sugar = physical change (icing sugar does not dissolve completely - like granulated sugar.)
  • Vinegar + cornstarch = physical change (the cornstarch forms a cloudy solution - it does not dissolve or react with the vinegar)
  • Vinegar + baking soda chemical change (bubbles are formed which indicates that a gas is produced)
  • Vinegar + baking powder chemical change (bubbles are formed which indicates that a gas is produced - baking powder contains baking soda and a dry acid)
  • Vinegar + powdered milk chemical change (precipitate forms; these are observable as clumps with a gooey texture)
line drawing of a lightbulb

Idea

The Physical or Chemical Change Identification chart could be completed by asking students to raise their hands for each powder.

 

Background Information for Teachers

Mystery Powders

We interact with solids and liquids on a daily basis. Whether that's in a hair salon, a kitchen, or in a science laboratory. Oftentimes solids and liquids are combined to create useful mixtures.

A hairstylist mixing dye over a sink
Hair stylist mixing hair dye (Source: Wicki58 via iStockphoto).
Image - Text Version

Shown is a colour photograph of a hand holding a container filled with white powder, and pouring white liquid into it.

A hand extends from the bottom edge of the image. It holds the handle of a grey container, half full of fine, white powder and a small whisk. A white bottle comes in from the top of the image. Thick white liquid is being squeezed from it into the powder. In the background is a large, stainless steel sink.

Different solids and liquids often look very similar. For example, flour and baking powder look almost identical but can not be used interchangeably. Using our five senses plays an integral role in determining the composition of unknown solids that look similar to other solids.

Jars filled with a variety of types of flours
Different varieties of flour in jars (Source: Maria_Lapina via iStockphoto).
Image - Text Version

Shown is a colour photograph of glass jars filled with different cream and beige powders. 

The camera looks down on a white table. Five clear glass jars are open, showing their contents. Each powder has a similar consistency, but a slightly different colour. These are shades of beige and cream.

Additional Resources

Reproducibles

Videos

Reproducibles and Media

Reproducibles

Videos

Science

Mathematical Thinking

  • Have students use standard volume measuring tools to make a food product in which solids and liquids are combined.
  • Have students explore ratios when measuring (e.g., If we use 1 tsp of baking soda and 4 tsp of vinegar, what is the ratio)?

Computational Thinking

  • Students could create an algorithm to explain to someone else how the powders were tested.

Visual Arts

Career Education

  • Students could brainstorm a list of people who would mix solids with liquids in their jobs (e.g., chef, baker, artist, hair stylist, construction worker, chemist, etc.).

Extensions

Science

Mathematical Thinking

  • Have students use standard volume measuring tools to make a food product in which solids and liquids are combined.
  • Have students explore ratios when measuring (e.g., If we use 1 tsp of baking soda and 4 tsp of vinegar, what is the ratio)?

Computational Thinking

  • Students could create an algorithm to explain to someone else how the powders were tested.

Visual Arts

Career Education

  • Students could brainstorm a list of people who would mix solids with liquids in their jobs (e.g., chef, baker, artist, hair stylist, construction worker, chemist, etc.).

Is there a difference between baking powder and baking soda? (Hands-on Activities)
Explore acid-base chemical reactions that really get things bubbling in the kitchen!

What happens when acids and bases mix? (Hand-on Activities)
Learn about acid-base reactions. Make your own pH indicator and test it with different solutions.

Physical and Chemical Changes in the Kitchen (STEM in Context)
Many physical and chemical changes happen when food is prepared. Chemistry never tasted so good!

Learn More

Is there a difference between baking powder and baking soda? (Hands-on Activities)
Explore acid-base chemical reactions that really get things bubbling in the kitchen!

What happens when acids and bases mix? (Hand-on Activities)
Learn about acid-base reactions. Make your own pH indicator and test it with different solutions.

Physical and Chemical Changes in the Kitchen (STEM in Context)
Many physical and chemical changes happen when food is prepared. Chemistry never tasted so good!

Saltsman, M. (Mar 13, 2018) Experiments with Salt and VinegarSciencing.

References

Saltsman, M. (Mar 13, 2018) Experiments with Salt and VinegarSciencing.

Reproducibles

Videos

Reproducibles and Media

Reproducibles

Videos

Science

Mathematical Thinking

  • Have students use standard volume measuring tools to make a food product in which solids and liquids are combined.
  • Have students explore ratios when measuring (e.g., If we use 1 tsp of baking soda and 4 tsp of vinegar, what is the ratio)?

Computational Thinking

  • Students could create an algorithm to explain to someone else how the powders were tested.

Visual Arts

Career Education

  • Students could brainstorm a list of people who would mix solids with liquids in their jobs (e.g., chef, baker, artist, hair stylist, construction worker, chemist, etc.).

Extensions

Science

Mathematical Thinking

  • Have students use standard volume measuring tools to make a food product in which solids and liquids are combined.
  • Have students explore ratios when measuring (e.g., If we use 1 tsp of baking soda and 4 tsp of vinegar, what is the ratio)?

Computational Thinking

  • Students could create an algorithm to explain to someone else how the powders were tested.

Visual Arts

Career Education

  • Students could brainstorm a list of people who would mix solids with liquids in their jobs (e.g., chef, baker, artist, hair stylist, construction worker, chemist, etc.).

Is there a difference between baking powder and baking soda? (Hands-on Activities)
Explore acid-base chemical reactions that really get things bubbling in the kitchen!

What happens when acids and bases mix? (Hand-on Activities)
Learn about acid-base reactions. Make your own pH indicator and test it with different solutions.

Physical and Chemical Changes in the Kitchen (STEM in Context)
Many physical and chemical changes happen when food is prepared. Chemistry never tasted so good!

Learn More

Is there a difference between baking powder and baking soda? (Hands-on Activities)
Explore acid-base chemical reactions that really get things bubbling in the kitchen!

What happens when acids and bases mix? (Hand-on Activities)
Learn about acid-base reactions. Make your own pH indicator and test it with different solutions.

Physical and Chemical Changes in the Kitchen (STEM in Context)
Many physical and chemical changes happen when food is prepared. Chemistry never tasted so good!

Saltsman, M. (Mar 13, 2018) Experiments with Salt and VinegarSciencing.

References

Saltsman, M. (Mar 13, 2018) Experiments with Salt and VinegarSciencing.