an Illinois Scientific Literacy Staff Development Grant

Here is an opportunity for your students, especially those at late high school, to present and defend their acid rain results to a professional in the field: Dr. Elaine AbuSharbain, Science Educator at Southern Illinois University at Edwardsville, has agreed to review any student designed experiments and their results, conclusions, inferences, and recommendations. Elaine's Email Address is: eabusha@siue.edu

Challenging Your Students to Be Problem Solvers: To make this experiment more challenging to your students, you might want to pose a question such as: What types of industries would be interested in the results of a growth hormone experiment? Design and conduct an experiment similar to this one using factors that effect growth other than the use of a growing hormone. Start by making a list of factors that effect productivity such as type of seed or soil used.

Student Instructions Available to download as a PDF file.

Needed Materials: Materials needed are the following: potting soil with no hormones added, Gibberellic acid (growth hormone sold commercially as Brellin ), scale, 4 packs of pea seeds (all of the same type), cups or pots to grow the plants in (be sure all the same type of container is used in growing the plants) Plants must be placed under artificial lights for at least 10 hours each day.

Safety Rule: Safety goggles must be worn when the solution concentrations are being made. Encourage students to wash their hands after they have completed making the solutions.

Procedure :

Student Information: The following information will provide you with the steps for making your varying concentrations of solutions and for implementing the steps to construct the potted plants. It is important to hold all of the variables constant except for the one being manipulated. The constant (or controlled variables) will be factors such as the following: the amount and type of soil, the container used, the pea seeds and the placement of the containers once the seeds have been planted. This placement needs to be directly under a fluorescent light or a plant light. The best placement is 35 to 46 centimeters above the top of the container. Also, the amount of plain water or concentrated solution will not vary once the watering process has begun.

Procedural Steps for Conducting the Investigation

• 1. In order to make the growth hormone solution, dissolve 2.5 grams of the Gibberellic acid into 50cc (mL) of normal tap water. This will result in a 5.0 % solution.
• 2. This 5.0% solution will be used to make the 2nd solution. Place 5cc (mL) of this 1st solution into a graduated cylinder.
• 3. Add enough water to reach the 50mL mark. You have now made a .5% solution.
• 4.You may continue to reduce the concentration of the solution in this manner.
• 5. Each solution should be placed in a labeled bottle with a tight fitting lid.
• 6. You are now ready to construct the experiment setup. Fill each container with soil. Place the pea seed at the recommended depth. Weigh the mass of the container, soil and seed. Attempt to get each container to weigh the same amount to within 1 to 2 grams. Record the weight of each container.
• 7. The number of containers will depend upon the number of different concentrations that are being used. Each concentration should have 4 containers. There should also be 4 containers that will be given only water. For example, if you are using a 5% solution and a .5% solution, you will need 12 containers total. (4-5%, 4-.5%, 4-no growth hormone) Label the containers according to the solution or tap water they will be receiving.
• 8. After you have planted the pea seed, water the group of 4 containers with either a concentrated solution or the plain tap water.
• 9. Now place the containers under the light.
• 10. The containers are to be watered with 10 mL of the differing solutions or plain tap water every other day.
• 11. Continue to water every other day for three weeks.
• 12. At the end of the third week, weigh each of the containers and record your results.
• 13. Create a data table to display your results.
• 14. After group and classroom discussions have occurred, login to enter your data.

Below is a list of questions that can be used to stimulate student discussions. If your students are at a developmental level where you are able to challenge their higher level thinking skills, then only present them with the first set of questions from each group below. Use the second list of questions as a way to stimulate thinking when you students seem unable to expand their knowledge on their own.

Examining Local Results

Discussion Questions that Require More Critical Thinking Skills:

Examining Local and Online Results

Discussion Questions That Will Require Critical Thinking Skills to Compare Local Data to the Online Data of Others

General Discussion Questions that May Occur as a Result of Comparing Local Data to the Online Data of Others

Performance and Multiple Choice Assessment Options

Links

Australian New Crops This website explains the effects of growth hormones on the world's most valuable legal crop, gingseng.

Agri-Grow Company selling a natural bio-stimulant and soil fertility booster.

Botany Lots of information about plants.

Plant Hormones and Plant Growth Regulators Explains plant hormones, their history, and how they work.

Plant Growth and Development A Concepts in Biology course that provides information about plant growth.

Enzyme is Crucial for Production of Plant Growth Hormone News Article.

Manipulating Plant Hormone May Help Crops News Article from the United States Department of Agriculture.

More links to Schoolyard Habitat Information

Schoolyard Habitat Links Learn more about developing and maintaining schoolyard and backyard habitats by visiting these links.

Copyright, 2005

by Prism Press

ALL RIGHTS RESERVED The text of this publication or any part thereof, may not be reproduced or transmitted in any means, electronic or mechanical, including photocopying, recording, storage in an information retrieval system, or otherwise, without the prior written permission of the authors.

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