Substances generally move across a cell membrane from an area of higher concentration to an area of low concentration. Factors such as changes in temperature, pressure, and concentration can affect the rate at which this movement occurs. In this assignment, you will plan an investigation into one factor and how it affects the rate of diffusion or osmosis.
Your task is to plan and conduct a simple experiment to test how one factor affects the rate of diffusion or osmosis using household items found around you. As an inquiry-based activity, you need to design your own experiment, including the following:
- Determine an appropriate ‘Testable Question’.
- Propose a reasonable hypothesis based on your ‘Testable Question’.
- Develop a procedure based on your ‘Testable Question’.
Step 1: Planning Your Experiment
- Determine the testable question you wish to investigate. Ensure that your testable question can be answered using quantifiable data and not simply qualitative observations.
- Once you have decided on your testable question, propose a reasonable hypothesis for the experiment you plan to conduct. Your hypothesis should explain how the change in your independent variable will affect your dependent variable. As previously stated, the change in your dependent variable should be quantifiable.
- Develop the procedure for the experiment you intend to conduct to test your hypothesis. Your procedure should be specific and detailed, allowing another scientist to recreate your experiment using the exact steps you used in your investigation. Write the steps of the procedure in the past tense.
- Upload your testable question, hypothesis, and planned procedure to the Assignment: Cellular Processes—Procedure Dropbox. Your teacher will review your work to ensure your experimental plan is correct.
A part of your grade for this assignment is directly linked to the completion of Step 1 of this activity. Your teacher will not only evaluate your initial effort but also your ability to implement the instructor’s feedback into your experiment.
It is strongly recommended that you submit Step 1 of this activity before conducting your experiment and finalizing your report.
Refer to the “Planning an Investigation” page in the Scientific Skills and Formatting module to help you plan your test.
Step 2: Conducting Your Experiment
- Apply any feedback from your teacher to your planned experiment.
- Conduct your experiment to test your hypothesis.
Step 3: Communicating Your Results
- Once you have completed your test(s), communicate your results in a lab report.
- Your lab report should include the following sections: testable question, hypothesis, materials, procedure (including your identified variables), observations, results, discussion, and conclusion.
Refer to the “Formal Lab Report” page in the Scientific Skills and Formatting module to help you write your report.
Performing hands-on lab activities is another way to learn and discover how science concepts apply to our everyday lives. However, it can also be dangerous if you do not take steps to perform these activities safely. We have made every effort to ensure that these activities are safe to perform in the presence of an adult (ex. teacher or parent). Use good judgment, and exercise every precaution in order to avoid accidents that may result in injury.
If you have any questions about the materials or procedure of a lab activity, email your teacher prior to beginning any lab activity.