ASSET » Student Experience 1: What happened to the fruit and vegetables?

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Purpose

To help students express their initial thinking about what happens when things decompose.

Description

Show students the following time-lapse video of a bowl of fruit and vegetables. Pause the video at 0:08 (before decomposition has started) and ask the students to name the fruits and vegetables in the bowl so that everyone is on the same page. Tell students that the video will show what happens to the fruit and vegetables over 74 days, with a picture taken every 40 minutes (36 pictures a day) and played back at 30 pictures a second. Ask students to make predictions about what will happen to the fruit and vegetables. Play the video, pausing from time to time to ask students to describe what they are seeing.

Next, tell students they will watch a time-lapse video of a pineapple taken over two months. Ask student to predict what will happen. Show students the first 50 seconds (after 50 seconds, the video plays in reverse).

Questions to Ask Students

Describe the material that is left in the bowl at the end of the first video.
- Are the fruits and vegetables in the same shapes that they began?
- How do you think it would feel if you touched it?
- Did you see anything in the bowl as time went on that wasn’t there at the beginning of the video?
Describe the material that is left at the end of the second video.
- Is the pineapple in the same shape as it was when it began?
- How do you think it would feel if you touched it?
- Did you see anything on the pineapple as time went on that wasn’t there at the beginning of the video?
What happened to the fruit and vegetables in the videos?
- If students say that the fruit and vegetables “rotted,” ask them to give a further explanation (i.e., “What does it mean to rot?”) and to describe what causes the fruit and vegetables to rot.
Have you seen anything similar in real life? Have you seen this happen with anything that is not fruits and vegetables? Not food?

Crosscutting Concepts

Cause and Effect ^[2] Posing questions to students about what happened and what caused the changes in the fruit and vegetables helps students begin to consider the possibility of underlying causes that may be invisible. Identifying these types of causes becomes increasingly important as students progress throughout the pathway.

Student Thinking

Students are often unfamiliar with decomposers and decomposition.
Some students believe that decomposition is a process that occurs in the absence of decomposers (i.e., that material decomposes on its own).
Others who accept that decomposition involves decomposers see the decomposers as the end station of the process; that is, they tend to think that decomposed material becomes a part of the decomposer rather than being converted into resources to be used by the ecosystem.
Some students are uncertain about which organisms perform decomposition.

Implementation Tips

The video sound is unnecessary for this student experience.
The first video is labeled as “decomposition,” so students will see the word. If students use the word, encourage them to explain what they mean.
Students may point out the fruit flies in the videos; if so, ask what they think the flies are doing. This is meant to help students share their initial ideas; at this point in the pathway, it is not necessary that they understand the fruit flies are helping with decomposition.
Students may point out the mold that appeared on some of the produce. Again, ask the students about the role of the mold. Similarly, it is not necessary for students to understand that mold is a decomposer at this point in the pathway.
Students might bring up the sprouts on the potatoes in the first video. This is a valid observation because the growth of the sprouts is a change, but it is not related to decomposition so there is no need to discuss at length.