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Marvelous Mixtures (Grade 5)

Master Teacher

Carlette C. Troy

Time Allotment

Three 50-minute class periods

Overview

A mixture forms when two or more substances are mixed together but their atoms are not combined. The parts of a mixture are easily separated.

A solution is a special kind of mixture. The substances in a solution dissolve, or separate, into their most basic particles. These particles are too small to be seen. In a solution, the particles of one substance are spread evenly through another substance. The substances in a solution can be solids, liquids, or gases.

One way to describe a solution is by naming its solvent and its solute. A solute is a substance that is dissolved in a solvent. A solvent is a substance that a solute is dissolved in.

Through activities presented in this lesson, including the use of video and the Internet, students will be able to design an investigation to separate mixtures based on their different properties and distinguish between solvent and solute.

Subject Matter

Physical Science

Learning Objectives

Students will be able to:

Discover what mixtures are;
Determine what solutions are;
Design an investigation to separate mixtures based on their properties;
Distinguish between a solvent and solute;
Investigate the effect of stirring, shaking, and crushing on the rate of dissolving of solutes.

South Carolina Standards

Visit the SC Standards Web site

Grade 5 IV A-1

Distinguish between a mixture and a solution, recognizing that a solution is one type of a mixture.

Design investigation to separate (by filtration, sifting, magnetism, evaporation, and flotation) mixtures based on their different properties.

Media Components

Video

Physical Science Series, Lesson 3: "Mixtures and Solutions."

Web Site

5^th Grade Science Quizzes provides an interactive quiz on vocabulary from the lesson.

Materials

Per student:

Activity Sheet 2: Focus for Media Interaction Questions
Activity Sheet 3: Marvelous Mixtures Assessment

Per group of four students:

1 screen
1 funnel stand
3 stirring sticks
4 filter papers
6 plastic cups
2 evaporating dishes

Per class:

6 spoons, 5-ml
2 containers powder
2 containers of sugar
2 containers of gravel
labels for cups
water
½ liter container for water
paper towels

Equipment

AverKey
television
VCR
overhead projector

(Note to Teacher: You will need an AverKey if you plan to display the Web sites to the entire class for interaction and discussion.)

Prep for Teachers

Prior to teaching the lesson, bookmark the Web site used in the lesson on each computer in your lab or classroom.
Cue the video.
Using Activity Sheet 1 as an example, make a transparency of a K-W-L chart.
Make copies of Activity Sheets 2 and 3.
Prepare the hands-on elements of the lesson:
Label the cups. Each group will use the removable labels and pencils to prepare two cups labeled "Gravel," two labeled "Sugar," and two labeled "Powder."
Have the students remove the labels at the end of the activity so the cups can be used again.
Have two pitchers of water on hand. Fill a half-liter container with water for each group.
Practice setting up the funnel stand.
Set up a Materials Station.

Introductory Activity

Step 1: Write the terms "Mixture" and "Solution" on a K-W-L chart that you made into a transparency. Ask the students to brainstorm all the things they think they know about a Mixture and about a Solution. Have them record their answers on the K-W-L chart. Accept all answers and observations.

Step 2: Tell students they are going to learn about how scientists classify mixtures and solutions.

Learning Activities

Step 1: Assign each group a different mixture to make. Several groups should make each of the following categories of mixtures:

Solid-liquid mixtures (for example: gravel and water, paper clips or Popsicle sticks and water, sugar and water, powder and water)

Liquid-liquid mixtures (for example oil and water, oil and alcohol)

Step 2: Give students their two materials and tell them to make a mixture. They may choose what amounts and how to measure the amounts of each material to add. Have available cups and different devises for measuring.

Step 3: Ask students to give their mixtures names and present them to the class. In the presentation, each student should describe what substances and the amount of each he/she used to make the mixture.

Step 4: As a class, classify each mixture by its components. Identify similarities and differences between each. Note the mixtures in which nothing appears to be floating-identify these particular mixtures as solutions.

Step 5: Closure for the day's lesson. Review the terms mixture and solution. Have students work in groups to apply their understanding of mixtures and solutions by listing as many solutions as they can think of that might be in their bathrooms or kitchens at home. Then have groups compare lists and create a class list.

Learning Activity (Day 2)

Step 1: Review what was covered the previous day. Provide students with a Focus for Media Interaction by asking students to record the names of as many mixtures and solutions as they can as they watch the video. They are to record this information on Activity Sheet 2: Focus for Media Interaction Questions, under Questions 1 and 2.

Step 2: START the clip when you see the word-MIXTURE, the commentator will be saying, "This rock called granite..." STOP the video after the commentator says, "As you can see this salad does not appear to be the same throughout."

Step 3: FAST FORWARD and START the clip when you see the word SOLUTIONS. The commentator will be saying: "Seventy percent of the earth is covered with water." STOP the video after the commentator says: ".carbon dioxide that are dissolved in the liquid." (Music will begin to play as a new segment starts on the video.)

Step 4: Tell students that today they are going to learn how to separate a mixture and a solution. Tell them that one thing common to all mixtures is that they can always be taken apart. Have them recreate the mixtures they made the previous day. When they have made the mixtures, ask the groups to think of techniques for separating the mixtures. Discuss their ideas as a class. Students might suggest pouring off the liquid using a screen or a filter.

Step 5: Tell students that a screen might come in handy for separating mixtures. Have each group follow this procedure for each mixture.

1. Place the screen on top of a second labeled cup.

2. Stir the mixture thoroughly. (Use a Popsicle stick.)

3. Pour the mixture through the screen.

Step 6: Let the groups try to screen all three mixtures. They will find that only the gravel and water mixture can be separated with the screen.

Step 7: Introduce the filter paper as a very fine mesh screen with holes so small they can't be seen with the naked eye.

Show the groups how to set up the funnel with a filter paper. Remind the students to stir the mixtures before filtering and to use a separate paper for each filtering.

Step 8: After the mixtures have gone through the filter paper, students are to open the filters and lay them flat on paper towels. The students will report out on which mixtures were separated by the filter paper. The students should report that the powder and water were separated, but not the sugar and water.

Step 9: Ask the students what happened to the sugar. Let the students explore the sugar and water mixture. (They should feel the grains of sugar). When a mixture cannot be separated using a filter, it is called a solution. A solution is still a mixture, but the solid dissolves so well that it cannot be filtered out. Sugar disappears or dissolves in water to make a sugar-water solution.

Step 10: Ask students what other solids they think will dissolve in water. Explain to students that the solids that dissolve in a solution are the "solutes." The substance into which the solids dissolve is the solvent-the solvent causes the solute to dissolve. Tell students that water is called the "Universal Solvent" because most materials dissolve in water.

Step 11: Ask the students what they could do to make the solute dissolve faster. Accept all reasonable answers. Tell students they are going to watch a video that will help them understand Rates of Dissolving. Provide your students with a Focus for Media Interaction by asking them to record this information on their Focus for Media Interaction Activity Sheet under Question 3.

Step 12: START the clip where the commentator says, "When adding chocolate syrup." and STOP the video when the screen fades to black and music begins to play.

Step 13: Ask the students to recall what they did in the first session and to describe the mixtures they made. Remind them that all mixtures once put together can be separated. Review how they separated the mixtures.

Step 14: Remind the students that the mixture of sugar and water could not be separated using a filter. Sugar and water make a special kind of mixture called a solution.

Step 15: To check for comprehension, ask students the following questions:

1. How are a screen and filter paper similar? (Both have holes and are used to separate mixtures.)

2. How are they different? (The screen has holes that you can easily see but the holes in the paper filter are so minute that you cannot see them without the aid of a magnifying glass.)

3. How would you try to separate a flour and water mixture? A salt and water mixture? (Flour by filtering, salt by evaporation)

4. Identify the solvent and solute in a saltwater solution. (solute-salt, solvent-water)

5. I have a solid material called citric acid. How would you find out if it forms a solution with water? (Add water to dissolve and filter the mixture.)

Step 16: Ask students to answer Question 4 on Activity Sheet 2.

Culminating Activity (Day 3)

Step 1: Tell students that they are going to separate a dry mixture made up of sugar, powder and gravel. Explain to students that in cooperative groups of four they are going to design an investigation to separate the sugar, gravel, and powder in order to return them to their original components.

Step 2: As the students watch, put 2 tablespoons of gravel, powder, and sugar in a half-liter container.

Step 3: Have all the previous materials available from earlier activities.

Step 4: Challenge each group to design a method to separate the three materials so that gravel ends up in a Gravel cup, the powder in a Powder cup, and the sugar in an Sugar cup.

Step 5: Meet with each group and ask them to describe briefly their plan for separation.

(Note to Teacher: The easiest way to separate the mixture is to add water to the dry mixture, use the screen to separate the gravel, and filter to separate the powder. Evaporation will separate the sugar.)

Assessment

Step 1: Have students complete Activity Sheet 3: Marvelous Mixtures Assessment.

Step 2: Have students go to the 5^th Grade Science Quizzes Web page. Click on Mixtures and Solutions Quiz 1. Provide a Focus for Media Interaction by asking them to answer the questions based on knowledge gained from completing their class work.

Cross-Curricular Extensions

Social Studies: Have students explore the areas of recycling, garbage separation and water pollution clean up.

Community Connections

0 Invite speakers from the Department of Health and Environmental Control to talk about their Environmental Outreach Programs that deal with reduction and recycling and waste management.

0 Invite speakers from your local environmental agency to discuss recycling with the class.

Student Materials

For groups:

1 screen
1 funnel stand
3 stirring sticks
4 filter papers
6 plastic cups
2 evaporating dishes