Traveling through different liquids

Author: Sharon Janulaw

Overview: Learners will observe and record what happens when they manipulate bottles containing one liquid and an object. They will compare bottles that have an object and different liquids. They will observe and record what happens when they manipulate bottles containing one liquid and more than one object.

Lesson concepts:

• Liquids have observable properties.
• An object's motion can be described.
• An object will fall more slowly in a stickier liquid.
• Science bases its ideas on evidence from 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.

Materials: Each group of six students will need:

• 12 identical clear plastic or glass bottles with caps
• Light Karo (corn) syrup
• Water
• 4 identical small screws
• 4 identical small nails
• 4 identical paper clips
• 1 small bowl with water
• 1 small bowl with Karo syrup

Advance preparation: Prepare the bottles for each group by filling six bottles with equal amounts of water (about two cups) and six bottles with equal amounts of Karo syrup (about two cups). Place the objects (screw, nail and paper clip) in bottles so that there is a screw in one bottle with water and in one bottle with Karo syrup, a nail in one bottle with water and in one bottle with Karo syrup, and a paper clip in one bottle with water and in one bottle with Karo syrup. Then place a screw and a nail in one bottle of water and in one bottle of Karo syrup, a screw and a paper clip in one bottle with water and in one bottle with Karo syrup, and a nail and a paper clip in one bottle with water and in one bottle with Karo syrup. 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: 40 minutes

Grouping: Small groups and whole class

Teacher background: When the objects are placed in the bottle, or when the bottles are turned upside down, the objects will move to the bottom of the bottles. Gravity causes the objects in the bottles to "fall." The liquid through which it is falling influences the speed at which an object falls. The stickier, or more viscous, the liquid is in which an object is falling, the more slowly the object will fall. The objects will fall more slowly through the syrup because it is the most viscous liquid used in this activity. Since water has very little viscosity, the objects in this activity will fall quickly through it.

Teaching tips: This lesson builds on what students learned in Exploring how liquids behave (www.understandingscience.org/lessons/how_liquids_behave.html).

Do not use plastic bottles with spouts or pour caps. It is very difficult to make those caps leak-proof. Before doing this activity with students, check to make sure the objects you selected will sink in the liquids. If the screws are not galvanized, they will rust in water after a few weeks, so you should replace the screws with identical ones and change the water frequently.

Procedure:

Whole group
1. Have a group discussion about what we learned about syrup and water when we investigated them in bottles last time (Exploring how liquids behave). Students can look in their Science Notebooks to help them remember. Have them share any questions they had. If possible, tell them what materials they can use to investigate to answer the questions they had.
2. Tell students that they will work in small groups and will use bottles filled with one liquid, either water or Karo syrup, with an object in it. Show them one of the bottles by holding it up without manipulating it in any way. Ask them what they think they could do with the bottle. Ask them to think about what will happen when they do what they suggested. Have them draw or write what they expect to happen in their Science Notebook. Hold up each bottle and ask students to record any questions they have about what will happen.
Small group
1. Students can work in groups of six. Tell them they will each have a chance to investigate all of the bottles. They should keep the bottle they are using closed and find out as much as they can about what happens to the liquid and the object(s) in the bottle. Have students think about what they will do when they are given a bottle. Tell students that you will put a bowl of Karo syrup and a bowl of water on the table so that they can feel the liquids if they need to remember how they felt.
2. Put a bottle on the table in front of each student and before they pick it up, have him/her tell you what they will do with the bottle and what they think will happen. Have students conduct their investigations and observe what happens. Remind students to keep the bottles over the table without touching the table. Guide them into thinking of turning the bottle upside down and watching how the objects move. Have them record their observations.
3. Give each student the opportunity to investigate each of the bottles. Have them record their observations as they investigate each bottle.
Wrap-up: Whole group de-brief
1. After everyone has participated in the small group investigations, bring the whole group to a discussion area. Hold up each of the bottles that contain one object 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 liquid and object and what they observed. You can have them tell what they saw and what they heard. Have them tell how the object moved in the liquid and what they think made it move that way. (They should be able to connect their explanation to how the liquids feel.) Have them share the evidence for their thinking.
2. Hold up each of the bottles that contain more than one object 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 liquid and objects 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.
3. Have students write any questions they have (or you record kindergartners' questions) in their Science Notebooks.
4. Review what they know about how scientists work and discuss what they did as they investigated.

Assessment: Have students write or draw something they learned about how objects move through different liquids. Have students write or draw something they did that it is similar to how a scientist would work.

Adapted from "What Will Happen If …. Young Children and the Scientific Method" by Barbara Sprung, Merle Froschi, and Patricia B. Campbell

An Understanding Science lesson
© 2010 The University of California Museum of Paleontology, Berkeley, and The Regents of the University of California