Effect of Ethylene on Fruit Ripening

Ethylene Gas Investigation

Subject Area: Chemistry

Grade Level: High School Chemistry

Lesson Title: Ethylene Gas Investigation

National Science Education Standards:

Science as Inquiry: 9–12

Structure and Properties of Matter: 9–12

Chemical Reactions: 9–12

Suggested Prior Knowledge: concepts of chemical changes; chemical properties of gases, especially diffusion of gases; basic organic chemistry (alkenes)

Purpose: To give students an understanding of how tomatoes ripen and what conditions allow them to ripen the best. To allow students to observe a chemical change that happens in nature.

Key Vocabulary:

chemical change—change in which a substance or substances are changed into a new substance or substances

diffusion—movement of a substance from an area of high concentration (lots of the gas) to an area of lower concentration (less of the gas)

ethylene gas—an organic compound, C2H4 (IUPAC name = ethene), the simplest alkene, which is a plant hormone

Objectives:

1. Students will design and conduct an experiment that allows them to observe the ripening of tomatoes under different conditions.

2. Students will be able to evaluate the effectiveness of various strategies for ripening tomatoes.

3. Students will discuss the role of ethylene gas in this process.

Materials (as needed depending on the design of the experiment):

-safety goggles (required)

-several green tomatoes on the vine

-small flowering plants or seeds

-paper bags (shopping bag size)

-cardboard box

-newspaper

-twine

-plastic bags (some are even commercially available that claim to ripen fruit)

-jars

-plastic containers made for ripening fruit or to keep fruit from ripening (available from department stores, Tupperware, etc.)

-refrigerator (optional)

Procedure:

1. Introduce the topic of ripening by displaying unripe and ripe fruit such as bananas, avocados, apples, and tomatoes. Discuss the role of ethylene gas in this process. You...