To explore how parts of something are related to the whole thing.
According to research, children do not appreciate that parts come together to make a whole that has properties that the parts do not. For children, wholes are like their parts. (Benchmarks for Science Literacy, p. 356.)
In this lesson, students will explore systems (in the context of parts and wholes), and develop the understanding that when parts are put together they can do things that they couldn’t do by themselves. They will analyze and discuss the parts of toys, classroom objects, and objects in the outdoor world.
The main goal of having students learn about systems is not to have them talk about systems in abstract terms, but to enhance their ability (and inclination) to identify the various aspects of systems in attempting to understand the whole system. Examining systems is really a way of thinking rather than theories or discoveries.
Note: This lesson was adapted from Project 2061’s Designs for Science Literacy.
Show students a simple, wheeled toy (e.g., dump truck). Ask students to identify and list as many parts of the toy as they can. If students don’t know the name of the part, they should make up a name. Display a list of 10-15 parts at the front of the room.
Divide the students into small groups. Each group should pick the part that seems most interesting to it and then answer these questions about the part:
- What does this part help the toy do?
- If this part were removed, would the toy still work?
- Is this part made of even smaller parts?
Discuss the findings with as the class. Students should classify each part as essential or nonessential (using words appropriate for your students; e.g., needed or not needed), justifying each categorization. When students say that a particular part is nonessential, counter with the question of whether the toy can really do its job without that part.
For example, show the separate wheel and ask: What can it do by itself? Accept all answers, eventually pointing out that the wheel is not very useful by itself. However, when it is combined with other parts, it can do many things. By this time in the lesson, it’s important for students to understand that when parts are put together they can do things that they couldn’t do by themselves.
Parts and wholes in the classroom
Organize the class into new groups, and have each group search the classroom to find something made of parts. Have them show another group (or you) one part of the whole item they have selected.
Next, have students find an item in the room that is NOT made of parts. Again, have them explain their findings to you or another group. (Note: Items not made of parts will probably be more difficult to find than items that are made of parts.)
Ask students this question:
- Are there more things in the classroom that are made of parts or more things that are not made of parts? Why do you think that? Give examples.
Parts and wholes in the natural world
If necessary, review the meaning of “manufactured” with the students. Then ask this question:
- Most of the things in our classroom are manufactured. Can you give me examples of such items?
To verify understanding, ask also for examples in the classroom of things that are not manufactured. (Possible responses: plants, fish, water, etc.)
Continue by asking these questions:
- Where could we go to find more things that are NOT manufactured? (Outdoors)
- If we went outdoors and looked at things that are NOT manufactured, do you think we would also find that most of those things are made of parts? (Accept all answers.)
- How could we find out? (Lead students to conclude that to find out the answer to this question they must go outdoors and look around.)
Next, have students work in groups to plan the expedition to find non-manufactured parts and wholes in the outdoor world. Students should plan, for example, where they will go, how long the trip should take, and how they will record their findings. Be sure students plan to identify items both made of parts and not made of parts. Allow student groups to plan and use their own means of recording data.
Have students carry out the investigation in the same groups in which they made their plans.
When students return to the classroom, ask this question:
- Did we find that more outdoor, non-manufactured items are made of parts or are not made of parts? Why do you think that way?
On the What are the Parts? student sheet, have each student draw a picture of one item observed outdoors that consisted of parts. Suggest that students find ways to make the parts on their drawings clear to others (e.g., outlining with a dark color, labeling a part).
Post the drawings and ask the students:
- Can you identify one part of the whole thing pictured in the drawing?
- What would happen to the whole thing if that part were removed?
In many cases, students will not know the function of the part or what would happen if it were removed. Do not tell them, but allow students to formulate questions and, where possible, design investigations to answer their questions. (You may wish to have students conduct some of these investigations at a later time.)
Raise the question of how the whole item would be affected if the parts were arranged differently. Be specific, asking, for example:
- What if this part [point to it] were here [point], instead of where it is? Could the whole thing still do its job?
Then ask these questions:
- If we repeated our investigation tomorrow, would we still find the same parts and wholes?
- What tools might help you see even smaller parts of the things you chose? (e.g., hand lenses, microscopes.)
Have several students summarize what was done today. Give time for them to share their comments and questions, things they liked or didn’t like in doing the lesson, etc.
Students should be able to make some interesting and accurate statements about how parts of something are related to the whole thing. Have students complete journal entries in which they list three general statements about wholes and parts based on their experiences. Review the meaning of the word “general” by giving or asking several students to give examples of general and specific statements.
You could also have students discuss and evaluate the methods they used for recording data during their investigation. They could enter in their journals one thing they learned about useful procedures for recording data, and one thing they learned about sharing information effectively through drawings.
Following are some activities that might follow this lesson:
- Looking for parts using hand lenses.
- Identifying parts and their functions in such items as oranges, seed pods, and isopods.
- Identifying all the parts and wholes you observe while eating your lunch.
- Restructuring block or Lego toy structures for new purposes.
- Pointing out differences in the parts of manufactured things and the parts of natural things.
- Investigating parts to see whether they can be separated clearly and distinctly from the rest of the whole or whether they merge gradually with the whole so that they cannot be separated clearly and distinctly.
- Allowing students to take apart some manufactured items, such as a bicycle bell, a telephone, or a clock. (First inspect the items to be sure they can be handled safely.)