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Exploring how liquids behave |
Author: Sharon Janulaw
Overview: Learners will be given bottles with one liquid in each, observe how the liquids behave when the bottles are turned and shaken, and record their observations. Then they will be given bottles containing two of the liquids, observe how the liquids behave when the bottles are turned and shaken, and record their observations.
Lesson concepts:
- Liquids have observable properties.
- Some liquids combine when they are mixed.
- Some liquids will not combine when they are mixed.
- Scientists ask and address questions about the natural world.
- Scientists observe, explore, and discover.
- Scientists work together and share their ideas.
- Scientists may revise their ideas based on new observations.
- Sometimes scientists disagree with each other.
Grade span: K-2
Materials:
- 12 identical clear plastic or glass bottles with caps for each group of six students
- Vegetable oil
- Light Karo (corn) syrup
- Water
- Food coloring (any color except yellow)
Advance preparation: Prepare six bottles by filling two bottles with water, two bottles with vegetable oil, and two bottles with Karo syrup. Prepare the other six bottles by putting one cup of food-colored water, then one cup of oil, into each bottle. For each bottle, screw the cap back on tightly.
If possible, read the students' Science Notebooks to prepare materials for investigations that will answer the questions they asked.
Time: 30 minutes
Grouping: Small groups and whole class
Vocabulary: vegetable oil, Karo syrup, heavier (denser), lighter (less dense), agree, similarities, differences
Teacher background: If two liquids will not combine when they are mixed, then the liquids are insoluble, i.e., one liquid will not dissolve in the other. Oil and water are two common insoluble liquids. Soluble liquids are those, such as water and Karo syrup that will combine when mixed to form one liquid, a solution.
If two insoluble liquids are combined in a bottle, no matter how much they are shaken, eventually the heavier (or denser) liquid will settle to the bottom and the lighter (less dense) liquid will rise to the top. In this activity, oil is lighter or less dense than water.
When you shake a bottle with two insoluble liquids in it, three different types of bubbles form. These are: air bubbles rising to the top of the bottle, bubbles of the lighter liquid also rising, and bubbles of the heavier liquid falling to the bottom of the bottle.
Teaching tips: This lesson builds on what students learned in Exploring liquids (www.understandingscience.org/lessons/exploring_liquids.html). Do not use plastic bottles with spouts or pour caps. It is very difficult to make those caps leak-proof.
Procedure:
Whole group
- Have a group discussion about what we learned when we used our senses to investigate liquids in the previous lesson — Exploring liquids. Students can look in their Science Notebooks to help them remember. Have them share any questions they had.
- Tell students that they are going to take a closer look at the three liquids. They will work in small groups and will use bottles filled with liquids that need to stay closed. They can gently shake, turn, and investigate in other ways that they think of to observe what the liquids in the closed bottles do.
Small group
- Students can work in groups of six. Tell them they will each have a bottle with one of the liquids. They should keep the bottle closed and find out as much as they can about the liquid in the bottle. Give each student a bottle and tell students to observe what happens when they move the bottle. If they are going to shake the bottle have them hold the bottle with two hands. Have them record their observations. Ask them to record what they think the liquid in the bottle is.
- Have each student pass their bottle to the person on their left. When they have their next bottle, have them investigate this liquid and observe what happens when they shake, turn, twist (or whatever else they think of doing). Have them record their observations. Ask them to record what they think the liquid in the bottle is.
- Again, have each student pass their bottle to the person on their left. When they have their next bottle, have them investigate this liquid and observe what happens when they shake, turn, twist (or whatever else they think of doing). Have them record their observations. Ask them to record what they think the liquid in the bottle is. If they continue passing the bottles until they've observed all six, they will observe the same liquid twice. If there's time, it might be interesting to find out if they notice that they've already observed each liquid and if they make the same or different observations.
- Collect the bottles. Tell students they will now each have a bottle filled with two of the liquids we have been investigating, but one of them has been colored with food coloring so it is easier to see when mixed with the other. Have older students write in their Science Notebooks what they think will happen when two of the liquids are put in the same bottle.
- Give each student a bottle with oil and colored water. Tell the students to investigate what happens when the two liquids are in the same bottle. They should record their observations and any questions they have. Ask them to observe what happens if they do the same thing again and again. If there's time, they could trade bottles with another person to look for similarities and differences.
Wrap-up: Whole group de-brief
- After everyone has participated in the small group investigations, bring the whole group to a discussion area. Hold up each of the first three bottles and ask students to think about what they did with the bottles and what they found out. They can look at their Science Notebooks to help them remember. Give students the opportunity to share what they did to investigate the liquids and bottles and what they observed. You can have them tell what they saw and what they heard. Have them tell what liquid they think is in each bottle and what makes them think that (they should be able to connect their explanation to the activity in which they used their senses to investigate the liquids in the bowls — Exploring liquids).
- Hold up a bottle containing two liquids and have students think about what they did and what they found out. They can look at their Science Notebooks to help them remember. Give students the opportunity to share what they did to investigate the liquids in the bottles and what they observed. Ask what they noticed when they tried doing the same thing again and again. Have them share the evidence for their thinking.
- Have students write any questions they have (or you record kindergartners' questions) in their Science Notebooks
- Tell students about how scientists work when they are investigating an idea.
(You can take a story about a scientist from a website or from publishers' materials. Select a story that has easily discernible similarities and differences in methods of investigation to what your students used.) Ask students to think about how they worked today. Have them talk to their neighbor about what they did that they learned scientists do based on the story you told them. Have them share their ideas. Discuss whether or not they always agreed with others and if they changed their ideas when they were investigating the liquids.
Assessment: Have students write or draw something they learned about what liquids do and what can happen when they are combined. Have students write or draw something they learned about how scientists work and how it is similar to how they worked.
Extension: Students can continue this investigation in Traveling through different liquids (www.understandingscience.org/lessons/different_liquids.html).