Activity 3.1: Predictions and Planning about Radish Plants Growing (50 min)

Target Student Performance

Students develop hypotheses about how matter moves and changes and how energy changes when radishes move and grow and make predictions about how they can use their investigation tools—digital balances and BTB—to detect movements and changes in matter.

Resources You Provide

(From previous lesson) Pre-Lesson 0.2GL Plant Growth Investigation Setup Worksheet
(From previous lesson) 1.2 Expressing Ideas and Questions Tool for Plants Growing
Time-lapse video of plants growing (http://www.youtube.com/watch?v=d26AhcKeEbE)

Resources Provided

Recurring Resources

(Optional) BTB Color Handout (1 per group)
Three Questions 11x17 Poster (1 per class)
Three Questions Handout (Color Version) (1 per student)
Three Questions Handout (BW Version) (1 per student)
(Optional) Investigation Planning Tool

Setup

This lesson helps students prepare for the Plants Investigations (Activities 3.2-3.4). An optional aid for this lesson is to have a ‘demo’ investigation setup to show students what they will be doing in the next lesson. If you chose to do this, see the materials list in Activities 3.2 and 3.3. Another optional extension to this lesson is for students to plan their own investigations. If you choose to do this, you may or may not want to have extras of the materials on hand in case groups of students want a closer look at their available materials. Optionally, print a few copies of the BTB Color Handout for students to use as a color reference.

Refer to the BTB Information and Instructions Handout for information about preparing BTB.

Print one copy per student of the 3.1 Predictions and Planning Tool for Plant Investigations. Prepare your computer, projector, and speakers for the Carbon TIME Growing Plants Video and the 3.1 Predictions and Planning about Radish Plants Growing PPT. Print one copy of the Three Questions 11x17 Poster and display it on your classroom wall. Print one copy of the Three Questions Handout for each student. Retrieve the materials from Activity 1.2. This may include a PPT slide from the lesson in which you typed students’ responses or a photograph of their sticky notes as well as the students’ completed 1.2 Expressing Ideas and Questions Tool for Plants Growing.

Directions

1. Use the instructional model to show students where they are in the course of the unit.

Show slide 2 of the 3.1 Predictions and Planning about Radish Plants Growing PPT.

2. Introduce Lesson 3.

Tell students that in this lesson, they will be investigating what happens when plants grow to learn more about what happens to matter and energy during chemical changes.

Use the link in slide 3 of the PPT (or above) to watch the short time lapse video of plants growing to prepare students to think about the investigation.

3. Review the Matter Movement Question.

Display slide 4 of the PPT. Put a copy of the Three Questions 11x17 Poster on the wall for reference if it is not there already. Give each student one copy of the Three Questions Handout or have them take out their existing copies.

Draw students’ attention to the poster and point out that each question is accompanied with “rules to follow” as well as ways to “connect atoms to evidence.”
Have students highlight, underline, or box the following rule about matter: Atoms are bonded together in molecules.

4. Review the Matter Change Question

Display slide 5 of the PPT.

Have students highlight, underline, or box the following rule about matter: Atoms last forever.

5. Review the Energy Change Question.

Display slide 6 of the PPT.

Have students highlight, underline, or box the following rules about energy: Energy lasts forever, and energy can be transformed.

6. Show students the first section of the Carbon TIME Growing Plants video.

Show slide 7 of the PPT.

Watch the video until the first intermission where Darryl and Nina ask the students to make predictions about what happens when plants are in the light and in the dark (from 0:00 to about 2:30).
Pause the video to discuss the questions posed on the screen before students complete the Predictions and Planning Tool.

7. Have students complete Part A of the Predictions and Planning Tool for Plants Growing.

Show slide 8 of the PPT. Pass out one copy of the 3.1 Predictions and Planning Tool for Plant Investigations to each student, and ask them to record their ideas as individuals for each of the Three Questions for plants growing

Remind students that these are just predictions, and that there are no wrong answers at this point. Encourage them to write down all of their ideas on the tool.

8. Discuss the Matter Movement Question as it relates to a digital balance

Show slides 9 and 10 of the 3.1 Predictions and Planning about Radish Plants Growing PPT. Discuss with students how a digital balance can be used to measure matter moving into or out of a system. Highlight that the mass of the system can be measured before and after a change happens in a system. Discuss the two possible conclusions students can draw from their observations:

If the mass of the system increases, then matter must have moved into the system (remember the facts about atoms)
If the mass of the system decreases, then matter must have moved out of the system.

9. Discuss how to account for the dry mass of plants.

Show slide 11 of the 3.1 Predictions and Planning about Radish Plants Growing PPT. Discuss how water makes up a large portion of the mass of plants. If you are following the gel protocol, remind students of their previous learning about this in the pre-lesson.

Have a discussion with students about their ideas about how they could measure just the mass of the plant that is not water. It may be helpful for them to think about foods that have had the water removed, such as dried fruits and herbs.

10. Discuss Matter Change Question as it relates to BTB

Show slide 12 of the 3.1 Predictions and Planning about Radish Plants Growing PPT. Discuss with students how BTB can be used to measure matter change in a system. Highlight that the BTB in a closed container can be observed before and after a change happens in the system. Discuss the two possible conclusions students can draw from their observations:

If the BTB changes from blue to yellow, then a chemical change may be producing CO₂
If the BTB changes from yellow to blue, then a chemical change may be using CO₂ as a reactant.

11. Discuss students' ideas about plants in the light and dark.

Show slide 13 of the 3.1 Predictions and Planning about Radish Plants Growing PPT. Discuss with students their ideas about how light energy is related to matter change in plants.

Consider with students how they might use BTB to determine the matter change that is occurring when plants are in the light and when plants are in the dark.

12. Have students complete their predictions for Ethanol Burning: Part B of the Predictions and Planning Tool.

Show slide 14 of the PPT. Have students find Part B on 3.1 Predictions and Planning about Radish Plants Growing PPT and ask them to record their ideas as individuals for both the matter movement and matter change questions.

Remind students that these are just predictions, and that there are no wrong answers at this point. Encourage them to write down all their ideas on the tool.

13. Have students discuss their predictions in pairs.

When students have completed Part B of their Predictions and Planning Tools, show slide 15 of the PPT. Divide students into pairs and tell them to compare and contrast their predictions with each other and to look for differences and similarities.

Give students 2-3 minutes to compare their predictions. As students are sharing, circulate through the groups. Consider engaging students by: Revoice what students said/wrote (for instance, I see/hear that you think BTB will turn blue). Why do you think that? What do you two disagree about? Why do you disagree?
Pay attention to the patterns in students’ predictions as well as predictions that diverge from any of the patterns. Both will be valuable to discuss next as a whole class.

14. Have students plan the investigation: Part C of the Predictions and Planning Tool.

Show students Slide 16 of the PPT and describe the instruments and materials necessary for carrying out the investigation. Have students begin planning their investigation. There are two main variations in how much control students can have over this planning process

Minimal student control: Discuss student ideas for how an investigation could be set up. Then have students follow the lab instructions for Activity 3.2.
Maximal student control: Students in class develop their own consensus plans that will replace the lab instructions in Activity 3.2. (They may use the Investigation Planning Tool for making their plans. Note the importance of having different student groups following the same plan so that they can come to a consensus about patterns in data in Activity 3.2.)
Some possible ideas of using lab materials are below:
- Students might choose to add controls to the experiment, for example including both a Petri dish of yellow bromothymol blue (BTB) (made from blowing into the blue BTB with a straw) and a Petri dish of blue BTB to the chamber.
- Students might also choose to set up a chamber with a Petri dish of blue BTB alone without the ethanol.

15. Save the Predictions Tools for later.

Display slide 17. Tell students that they will revisit their ideas after the investigation to see how their ideas changed over time.

Assessment

During the class, listen to the ideas students offer in step 8 of the activity. Do students’ predictions follow the rules? At this point, do not correct student ideas, but listen for what they say about matter and energy in the context of plant growth. After class, use the 3.1 Assessing the Predictions Tool for Plant Investigations to compare your students’ work with what we would expect to see in Level 4 responses.

Ideally, the discussion about the Predictions and Planning Tool in this activity will reveal a range of student ideas. Some students will have Level 2 ideas with respect to the principles (matter and energy) and context-specific knowledge (how a plant grows). Listen to see if students have a sense of necessity about connecting mass changes and movement of atoms, and if they recognize that if the plant gains mass, then atoms must be moving into the plant. Also, listen to see if students account for energy separately from matter (Levels 3 and 4), or if they suggest that some of the matter in the plants might be converted to energy (Levels 2 and 3). You do not need to correct any problems now; they will be addressed through the investigation and modeling in the activities to come.

Tips

Have a designated place in the classroom where students store their Expressing Ideas and Questions and Predictions and Planning Tools so they can easily refer back to their ideas at the end of the lesson.
Expect some students to make the right predictions for the wrong reasons. Note in particular whether they say that changes in the mass of the gel indicate that atoms are moving.

Differentiation

Refer back to Systems & Scale or Animals Predictions and Planning Tool as a model
Strategic grouping with strong speakers
Provide sentence stems for discussion and filling in the predictions tool.
Read Three Questions Handout as a group by referring back to Systems & Scale or
Allow students to use personal devices to watch the plants growing videos. Allow for slowdown and playback.
Give examples of answers to the Three Questions and possibly post these as sentence stems for students.
Keep student predictions in a safe place (notebook or class file).

Modifications

Document the thinking of the whole class on a large poster.

Extending the Learning

Have students plan and carry out their own investigations to answer the Three Questions. If groups get unreliable data, you may want to carry out the investigations as planned in this Unit, at least as a demonstration.
Have students review their notes about plant growth that they have been collecting since the Pre-Lesson. Discuss what is similar, different, or surprising about this method of growing plants compared to more familiar methods.