Lesson 87. Standard & Objective: S1 O2c Materials: Indoor Sparklers

Transcription

1 Lesson 87 Standard & Objective: S1 O2c Materials: Indoor Sparklers

2 Lesson 87 8 th Grade Mr. Petersen Bonneville Junior High

3 Self Starter * 20 Points * 2/7/2015 * Lesson 87 Today s Learning Objective: A chemical change has probably occurred if bubbles are released, there is a change of color, or an odor is produced. Review Question: What type of change occurs when a penny oxidizes? Answer: Chemical Homework: Nothing

4 8 th Grade *Glossary List * Portfolio 6 [ 1] 1. Atom- 2. Molecules- 3. Oxidation- 4. Combustion-

5 Assignment Number Assignment Log * Portfolio 6 Assignment Title Lesson Number 1 Glossary PowerPoint Questions Lessons Deoxidize a Penny Lab

6 Call on 14 students to read.

7 Introduction * Student Read Reader 1: You hit a baseball out of the park and head for first base. You re excited. The score is tied, and now your team has a chance of getting a winning home run. Then you hear a crash. Oh no! The baseball hit a window in a neighboring house. Reader 2: The glass has a big hole in it, surrounded by a web of cracks (see Figure 1). The glass has changed. It s been broken into jagged pieces. But the glass is still glass. Breaking the window is an example of a physical change in matter.

8 Teacher Read: FIGURE 1: When glass breaks, its physical properties change. Instead of one solid sheet of glass, it now has holes and cracks.

9 Student Read: Physical Change in Matter Reader 3: A physical change in matter is a change in one or more of matter s physical properties but the identity of the matter does not. Reader 4: Glass breaking is just one example of a physical change. Some other examples are shown in Figure on the next slide and in the video (see link below). Reader 5: In each example, matter may look different after the change occurs, but it s still the same substance with the same chemical properties. For example, smaller pieces of wood have the ability to burn just as larger logs do.

10 FIGURE 2: In each of these changes, only the physical properties of matter change. The chemical properties remain the same.

11 Physical and Chemical Change * 1:52

12 Teacher Read *Chemical Changes in Matter Because the type of matter remains the same with physical changes, the changes are often easy to undo. For example, braided hair can be unbraided again. Melted chocolate can be put in a fridge to reharden. Dissolving salt in water is also a physical change. How do you think you could undo it?

13 Student Read Reader 6: Occasionally a physical change cannot be undone. An example would be grinding a piece of wood into sawdust. Reader 7: Such a change is irreversible because the sawdust cannot be reconstituted into the same piece of wood that it was before. Reader 8: Cutting the grass or pulverizing a rock would be other physical changes that cannot be reversed.

14 Teacher Read Communities often use fireworks to celebrate important occasions. Fireworks certainly create awesome sights and sounds! Do you know what causes the brilliant lights and loud booms of a fireworks display? The answer is chemical changes.

15

16 What Is a Chemical Change? Student Read Reader 9: A chemical change occurs whenever matter changes into an entirely different substance with different chemical properties. Reader 10: A chemical change is also called a chemical reaction. Many complex chemical changes occur to produce the explosions of fireworks. An example of a simpler chemical change is the burning of methane. Reader 11: Methane is the main component of natural gas, which is burned in many home furnaces. During burning, methane combines with oxygen in the air to produce entirely different chemical substances, including the gases carbon dioxide and water vapor. Reader 12: You can watch some very colorful chemical changes occurring in the next video.

17 Chemical Changes * 2:53

18 Student Read: Identifying Chemical Changes Student Reader 13: Most chemical changes are not as dramatic as exploding fireworks, so how can you tell whether a chemical change has occurred? There are usually clues. You just need to know what to look for. Student Reader 14: A chemical change has probably occurred if bubbles are released, there is a change of color, or an odor is produced. Other clues include the release of heat, light, or loud sounds. Examples of chemical changes that produce these clues are shown in the Figure 3 on the next slide.

19 FIGURE 3: Evidence that a chemical change has taken place.

20 Teacher Read Fireworks produce heat, light, and loud sounds. These are all signs of chemical change. You can learn how fireworks produce these signs of chemical change by watching the video on the next slide.

21 Fireworks * 1:47

22 Demonstration Sparklers Are they safe indoors? I guess we ll find out!! No, we better go outside to do this activity.

23 Formal Assessment 1. How much of the air we breathe is nitrogen? 2. List 2 chemical reactions. 3. List 2 physical reactions. 4. Gunshots are very loud sounds. Does this occur because of a chemical reaction?