Lesson 4 of 9
Objective: Students will be able to cite examples of similar changes that heating has on the observable properties of objects or materials.
I will begin this lesson with a strategy that I call the guess box. The purpose of the guess box is to display objects to students one at a time. After each item is pulled from the box, the students have to identify what all of the items have in common. In the end, all of the items must have one characteristic in common. I no longer use an actual box, because it is more convenient to use my promethean board because it does not require me to go out and purchase the items. For this lesson, I will show students photos from a collection on my promethean board. I will have a stationary box on the board that I can pull my photos out of for the students to guess. The photos I will use in this collection are: raisins, prunes, banana chips, apple chips, beef jerky, and toast.
I will ask students to identify what each item has in common as they are pulled from the box. I will chart their responses on chart paper. If a student's guess no longer applies when a new object is pulled from the box, then their guess will be eliminated from the chart. This allows the students to have an accurate resource to view when drawing conclusions.
Once all of the objects have been pulled out of the box, I will ask the students questions such as, "what do the objects in the entire collection have in common? How are the objects related? How can the objects be grouped in the same way and how have the objects changed?" We will discuss that the objects have been dried, hardened or firmed. I will ask the students to predict what caused the objects to change and what tools or methods were used.
Next, with an elbow partner, I will provide time for students to discuss why people would want or need to change the physical properties of foods by heating them. I will allow the students the opportunity to share their ideas with the class.
I will present the question, "What non-food items could we add to the collection that shows similar changes when heated?" I will ask student to brainstorm responses.
To conclude the exploration session, I will arrange the students into groups. I will explain to students that heating promotes melting. I will instruct the students to brainstorm a collection of items that melt when heat is applied. I will provide each group with a piece of poster paper to create their collections to present to the class and compare with the class.
At the end of the exploration session of the lesson, students will be asked to transition to the carpet to prepare to present their collections with the class. As the students present their collections, I will ask them to explain why they believe people need or want to heat items to melt them. I will also ask the students to explain the criteria they used to justify their selections of the objects that they placed in their collections. All groups will present their collection.