Jill Kesinger

10/4/2000 & 10/5/2000

Brief description- to interpret which observed change is physical and which is chemical.

Grade-6th

Standard- Distinguish between the physical and chemical changes in matter.

Background information- Properties of matter can be classified as physical and chemical. Most changes in matter can be classified in the same way. Physical change does not alter the identity of a substance. The shape of a substance can be altered, but the actual substance cannot be changed. Chemical change actually alters the material as it reacts to certain substances.

Concepts covered in lesson-

  1. Identify a chemical change as an important chemical property in matter. Likewise, identify a physical change as an important physical property of matter. Matter is constantly being changed.
  2. Distinguish between chemical and physical changes due to the reactions occurred. Chemical changes take place and form new substances that have new properties. Physical changes include changing shape, size, or state of matter and the original identifying properties may be recognized.
  3. Physical properties are can be observed in physical changes.
  4. Chemical changes include chemical make-up of a substance.

Materials and equipment-

Per group: one clear cup, water, one seltzer tablet, bits of tissue, one tablespoon of soil, bits of chalk, one tea bag, pieces of steel wool, liquid soap, dried beans, and a table worksheet.

Procedures-

  1. Ask the groups to sit with their provided groups.
  2. Ask the students to tell what prior knowledge they know about chemical and physical changes. Make a list on the board of the students’ comments. Then tell the students that in the next two days we are going to investigate and prove the difference between the two changes.
  3. Ask each group of students to fill each cup or jar half full of water. Give the group one of the following materials: a seltzer tablet, bits of tissue, soil, bits of chalk, a tea bag, steel wool, liquid soap, or dried beans. Have each group add its materials to the water in the jar and stir the contents.
  4. Have each student record the results of the worksheet.
  5. Bring the students together by asking them to discuss their groups’ observations. Next, write down your predictions on what kind of change will occur and what it will look like.
  6. Once the groups have predicted what kind of change they will have, ask them to share with the class. One group at a time may discuss their ideas.
  7. Ask the students to finish filling out their data worksheet.
  8. On the second day, have the children observe one another’s jar. Ask them to sit at their table first, then rotate to the right once prompted to do so. Remind them to take notes on what they observed.
  9. Bring the students together and ask several questions. On a dry erase board, complete a class chart with the majority of the answers. Ask the students what happened to each substance? How do we know the difference between the two changes with items such as these? What are other examples of chemical and physical changes?
  10. Ask the students to work as a class to "create" a physical change. How could we act as a physical change?

Assessment- The students can be assessed by listing on a sheet of paper, the differences between physical and chemical changes. In their groups, the students may also create their own way to show a chemical or physical change by using creative drama.

Useful Internet resource- www.nytimes.com/learning/teachers/lessons/991228tuesday.html

Other Sources- Pathways for Learning

Science process skills- Observation and data collecting.

 

Jill Kesinger

Chemical vs. Physical change lesson critique

This was the first ICM lesson that I had taught. I was concerned with the students ability to investigate own their own, without much guidance. I did not have much experience with the children, yet the lesson was appropriate for the time frame, so we went ahead.

The beginning of the lesson asks the students to inform me about what knowledge they already knew about chemical and physical changes. On the board, we made a list. I was surprised as to how much the students already knew about the differences between the two changes. The important aspect of them defining each was that the students confused which change was which and disagreed on a particular definition of each. They did not have a clear understanding and I was relieved to know that they could learn for themselves the differences and disprove or prove their original theories. The students had originally said that physical changes were: those that did not change the object, stayed the same shape or structure, were transformed to something else, and those that changed forms of matter. The knowledge about chemical changes was similar: those objects that change materials, those that did not change materials, and were broken down into other chemicals. Knowing this, the students were able to decide what was a chemical change vs. what was a physical change.

The class I teach typically has a wonderful manner. However, they are a range of students who do not work well in groups. Since the students do not like working cooperatively, the task of them discussing their observations was difficult. Students had a hard time talking about what they predicted to happen to their object and what it would look like. I feel that individual work would have been much more successful. Since it was so easy for them to get off task, if they were required to fill in their data sheet and written predictions individually, I feel they would have had a better opportunity to teach themselves the concepts. If the students solely decided for themselves what their object would look like, they could have been able to begin to create a difference, in their minds, between the two changes. Then I could have followed up with discussion and questions about the types of changes.

But if they did this individually, there wouldn’t be time for them to each share what object they had and what their predictions were, letting them work with only one substance. I think that either way connections are lost and the student’s focus is directed to something else. What I would have liked to see was each student manipulating a particular substance, then observing and predicting, in a clockwise fashion, all the other student’s items.

We were able to make predictions about each substance. Generally, one student from each table remained on task and was able to tell their predictions. I thought that the children would benefit more by rotating to each table, and be required to write down a prediction about each substance. With an appropriate data sheet, deciding each prediction would again, help them begin to draw distinctions between the two.

The colloquium was the most interesting part of the lesson. This is a relatively large class and the students were asked to name their predictions as I wrote them down on a dry-erase board. As I did this, students were talking about other subjects, distracting others and overall, not paying much attention. I lost class management completely. We were able to graph predictions and what actually occurred. Then I began to prompt them with questions. I found that this was a better way for them to remain on task, rather than them calling out predictions and conclusions randomly. The students were simply not used to a discussion- based lesson. Because of this, I found them interrupting others, distracting kids, and overall giving them an excuse to talk. However, the best question I asked was "how do we know the difference between a chemical and physical change now?" Gian, a very intelligent student, responded with, "physical properties may change with a physical change, but it will still remain the same object". I think that students could form ideas about the changes here. Then I asked, "What are physical properties?" Students responded with various answers, but they did note that physical properties were the same as characteristics of a particular substance. I asked then what was the definition of a physical change. They responded with many answers that I wrote on the board. We concluded that a physical change was one that could change characteristics yet keep the same original substance. I enjoyed that we could all have our input on the deciding a definition of the change. The students who were participating all felt apart of "uncovering" an unknown concept.

Because the students were so rowdy, I asked them to return to their tables. From there we went on to decide a definition of a chemical change. With the students back in their usual setting, they were more able to pay attention. Again, here we wrote down each student’s idea of what a chemical change was, and then decided collectively a definition.

With the creative drama, the students enjoyed moving about the classroom. I asked them to decide on a way that they could create a physical change. One particular student thought to create a pumpkin then they would carve it and form pieces of the pumpkin. I was impressed with his genuine idea, and the students saw yet another demonstration of a physical change. I enjoyed this and so did the children, because everyone got to participate. Even the students, who had not originally followed along, became a part of the concept. I’d ask the lower students to explain what they were performing. Kentariuos, a particular struggling student could answer in his own words.

I believe that this is a good lesson, but the main challenge I faced was the students getting distracted by other interests. To improve the lesson, I feel that the students should work individually to find predictions and conclusions. There would be more time for them to think about the concepts and it would also be an accurate assessment of what knowledge they have gained. Then during a colloquium discussion, I could call upon the students who had important ideas from their written comments. This way, they could mention relevant ideas and I could direct where the discussions were headed. I do feel calling on students who have made the connections is a much better way to facilitate discussion, rather than losing control because of the students lack of structure. Ultimately for me, leading the colloquiums would have made the children’s connections stronger.