Beacon Lesson Plan Library

Combustion or Lack of Oxygen

Rosemary Wilson
Santa Rosa District Schools

Description

Students are able to see the combustion of ethanol and then write a report regarding the inability for the ethanol to ignite a second time.

Objectives

The student knows that investigations are conducted to explore new phenomena, to check on previous results, to test how well a theory predicts, and to compare different theories.

Materials

- Commercial water bottle
- Denatured ethanol
- Matches
- 400 mL beaker

Preparations

1. Purchase a commercial water bottle from an area store which sells large bottled water.
2. Have the denatured alcohol, matches and beaker on the demonstration table for use.

Procedures

This demonstration is to be accomplished after a lecture on the types of chemical reactions. Combustion reactions require oxygen and this is an important point for successful understanding by the students. Invite the students to gather around the demonstration table.
1. At the demonstration table in your lab, pour approximately 5 mL of denatured ethanol into the commercial water bottle, then swirl it around the bottle to allow the alcohol to cover all surface areas of the bottle.

2. Pour the excess alcohol out of the bottle into the 400 mL beaker.

3. Have a student turn off the lights for the classroom. Make sure there are no students too close to the demonstration table and there are no combustibles nearby. Place the 400 mL beaker with the excess alcohol away from the demonstration table.

4. Strike a match and drop it into the water bottle. The alcohol will ignite which makes a loud noise and gives off light.

5. After the initial combustion reaction, ask the students if they would like to view the reaction for a second time.

6. Follow the same procedure of pouring in 5 mL of alcohol, swirling to cover the surfaces and then pouring out the excess alcohol.

7. Strike a second match and drop it into the water bottle.

8. When the acohol fails to ignite the second time, ask the students to explain why this has occurred.

9. Explain to the students that the alcohol needed oxygen to combust and the available oxygen had been used by the first demonstration. The diffusion of oxygen back into the bottle might take some time to occur.

Assessments

1. Students will be required to write a five paragraph report, to correlate with the FCAT writing assignments, which is graded as a lab report.

Extensions

1. Lecture on the types of chemical reactions.
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