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Introduction to Osmosis

Comparison of animal cell and plant cell In this hands-on, minds-on activity, students investigate the effects of hypotonic and hypertonic solutions on eggs that have had their shells removed. As students interpret their results, they develop a basic understanding of the process of osmosis. As they answer additional analysis and discussion questions, students learn about the effects of osmosis on animal and plant cells and apply their understanding of osmosis to the interpretation of several “real-world” phenomena.

Download Student Handout: PDF format or Word format

Download Teacher Preparation Notes: PDF format or Word format

The Teacher Preparation Notes provide instructional suggestions and background information and explain how this activity is aligned with the Next Generation Science Standards.

We invite comments on this Hands-On Activity and the accompanying Teacher Preparation Notes, including suggestions for other teachers who are planning to use the activity, useful preparatory or follow-up activities, additional resources or any questions you have related to the activity, or a brief description of any problem you might have encountered. If you would prefer to send your comments or questions in a private message, please write Ingrid Waldron at iwaldron@sas.upenn.edu.

Comments

2022 revision

Submitted by iwaldron on Wed, 10/19/2022 - 3:33pm.

Revisions include addition of anchoring phenomena at the beginning of the Student Handout, a brief explanation of the currently favored hypothesis about the molecular mechanism of osmosis at the end of the Teacher Preparation Notes, and numerous revisions for clarity in both documents.

Ingrid

2019 revision

Submitted by iwaldron on Thu, 12/12/2019 - 1:50pm.

I have revised, reorganized and streamlined the questions in the Student Handout to improve clarity and student learning.
Ingrid

2018 revision

Submitted by iwaldron on Fri, 09/14/2018 - 5:04am.

The Student Handout has been reorganized to begin with the egg experiment and engage students in figuring out what happened as they develop their basic concept of osmosis. In subsequent sections, students refine and apply their understanding of osmosis. Many of the questions have been revised to promote better student understanding of osmosis.

2016 Revision

Submitted by iwaldron on Thu, 10/27/2016 - 2:55pm.

To enhance student understanding, some figures have been added to the Student Handout and some of the questions have been revised and reorganized. The Teacher Preparation Notes have been expanded to include more background biology and instructional suggestions.

good info.Thanks for clear

Submitted by nandinisree (guest) on Mon, 06/27/2016 - 7:24am.

good info.Thanks for clear explaination.Here is an interesting Osmosis app from ajax i found it is a quick and easy to experiment with various solutions on different concentrations in the experiment to determine the osmosis values .

2015 revision

Submitted by iwaldron on Fri, 09/11/2015 - 3:09pm.

To further student understanding, the wording and sequence of the questions in the Student Handout have been revised. Additional explanations and resources have been provided in the Teacher Preparation Notes. Also, since recent evidence has cast doubt on some of the content previously included in the Student Handout, this disputed material has been moved to the Teacher Preparation Notes with suitable explanation and disclaimer.

2014 revisions

Submitted by iwaldron on Thu, 07/31/2014 - 9:56am.

The experiment with dialysis tubing has been replaced by a demonstration of osmosis in eggs. A version of the dialysis tubing experiment is available in "Diffusion across a Selectively Permeable Membrane" (/sci_edu/waldron/#diffusion). Most of the questions in the Student Handout have been revised for greater clarity or interest.