5 Ways to Make ‘Osmosis and Diffusion’ A More “Permeable” Topic

Akanksha Saxena

Introduction: Osmosis and Diffusion

When one learns how cells in the body receive food, water, nutrition, and signals, cellular transport becomes an intriguing and thought-provoking subject. There are 2 principal ways by which cellular transport is accomplished. They are active and passive transport mechanisms. All the energy (ATP) driven mechanisms are placed under the category of active transport. On the other hand, all the mechanisms that don’t require energy (ATP) are passive forms of cellular transport, diffusion and osmosis being two of them.

The theoretical concepts of diffusion and osmosis are applicable in a wide range of everyday activities. Diffusion and osmosis are at work everywhere, from ‘the swelling of chia seeds in your overnight soaked oatmeal’ to ‘the operation of a water purifier system’ and ‘the determination of the saline solution administered by the doctors to you in the operating room’ to ‘the oral rehydration solution (ORS)’.

There is no biological cell that doesn’t conduct these 2 processes as the basic sustenance of the cell is dependent upon them. Students are frequently left in a quandary when discussions about this topic begin in class.

For teachers and educators dealing with this subject, we have strived to gather some resources in this article. As you read, you’ll be portrayed with the basic issues that students face while learning these 2 passive modes of transport. We’ll also provide some practical solutions to overcome those issues. We, at Labster, understand that teachers and educators, though passionate about their respective subjects, fall short due to a lack of resources and guidance. 

Continue reading to gain useful perspectives. By the end, we’ll convince you why a virtual lab simulation will prove helpful not only for your students but also for you as an educator to deliver concepts more efficiently.

3 reasons why ‘Osmosis and Diffusion’ can be tricky to teach or learn

There are 3 major reasons why students are overwhelmed by the topic of Osmosis and Diffusion. Acknowledging these issues is the first step toward making the topic more approachable. 

Students are often heard saying this:

1. It feels conjectural and not applicable to real life

Students frequently express their dissatisfaction with the topic of osmosis and diffusion, claiming that it is too abstract and philosophical for them. Failing to relate ‘the different types of cellular transportation mechanisms’ to the ‘essential body functions’ is challenging. But can we blame our students for it??? The answer is NO! 

Osmosis and diffusion have always been taught as two random biological processes, without a comprehensive understanding of the crucial roles they play in the development, maintenance, and growth of a living creature.

2. It adds no value to my life

Since many students believe it has no practical application to their lives, studies, or careers, students undervalue the lessons they can learn from this topic. Even the teachers might not be able to quote pertinent examples which can be compelling for students to learn more about osmosis and diffusion. On the contrary, classes are mostly about rote learning of concentration gradients, solute-solvent-solution debates, and cramming definitions of hypotonic, hypertonic and isotonic solutions. 

3. It doesn’t increase the scope of my understanding but rather complicates it

Osmosis and diffusion are frightening topics for students who already find basic biochemistry concepts intimidating. Instead of expanding the reach and capacity of their current knowledge system, this interferes with their brain. Not understanding the fundamental properties of cell membranes (permeable, impermeable, semi-permeable, or selectively permeable), units of concentration and their interconversions, the directionality of solute or solvent movement, the logic behind the movement of molecules, and many other related topics could be a complicated situation.

5 ways to make ‘Osmosis and Diffusion’ a more approachable topic to understand

To address the issues encountered while teaching Osmosis and Diffusion, educators can engage the under-listed solutions in their next classes. These can shed light on how to handle each issue that students encounter. They will not only make lessons clearer and simpler for your pupils to understand, but they will also make teaching easier for educators like you.

1. Share tales that exemplify the virtues of the topic

Teachers can start by making the benefits of osmosis and diffusion evident to their students to overcome the criticism of the topic being “too abstract and conjectural”. They can share stories of how these essential life-sustaining processes were first identified.

Jean-Antoine Nollet, a physicist, and a catholic clergyman, popularly known as Abbe Nollet, discovered the amazing science behind osmosis. Who knew that a basic science phenomenon would be first observed and elucidated by a practicing full-time physicist? In 1748, Nollet discovered this science that ensures essential kidney function (cleansing of blood), the most fundamental process of autotrophic behavior of plants (photosynthesis), and what we today apply in our home water purification systems (reverse osmosis/RO technology). 

While his main forte of research was electricity but being a curious person as he was, Nollet initiated an experiment to see the movement of fluids across cell membranes. He filled a vial with alcohol and secured its opening with a piece of damp pig bladder (serving as a cap). He ensured that no air could enter the vial. To further reduce the possibility of air entering the alcohol, he next placed this vial in a sizable water-filled vessel. When Nollet removed the vial after around 5 to 6 hours, he noticed a recognizable swelling in the bladder. It was on the verge of exploding. When he pierced the bladder with a needle, the alcohol from inside the vial shot into the air…

This was a powerful demonstration of osmosis in action. The discovery of a natural method by which water travels in between the cells without the requirement for energy was an incredible finding because water makes up the majority of biological bodies.

Sharing powerful stories like this can not only make the concept clearer to your students but deliver deeper insights as to why osmosis and diffusion are worth studying and discussing in scientific fields.

Figure: Jean-Antoine Nollet, the discoverer of “osmosis”. Image Source

2. Simplify the terminologies

Usually, students are caught up in the difficult terminologies of the subject. Educators have to break down the complex terms like hypertonic, hypotonic, isotonic, freely permeable, impermeable, semi-permeable, selectively-permeable and so many more of them. We offer some simple tips and tricks to help your students cope with this.

  • Types of solutions: Hypertonic solutions make the cells lose their water and shrink them to a smaller size. It can be explained by the wilting phenomenon when you forget to water your plants. Hypotonic solutions make the cells gain more water and bulge. It can be explained by the bulging of raisins or the gelatinous layer formation of chia seeds in the overnight soaked oats. Isotonic solutions don’t affect the size of cells as they allow equal directional movement across the selectively permeable membrane of cells.

osmosis diffusion blood

Figure: An image showing the application of the hypertonic solution to the blood cells to see its effect on the cell’s structure, size, and shape. It is available in the Osmosis and Diffusion simulation from Labster. The simulation is available for High School and University/College courses.

  • Types of membranes: Freely permeable membranes can be described as a house with huge windows and doors but with no option to close them. Light, insects, and invaders can all set foot into your private territory. Impermeable membranes can be described as a house with only stone walls and no windows or doors (like a dungeon/cell in Game of Thrones). Semi-permeable membranes can be described as a house with numerous unreachable windows that you can’t even close. They will let things and invaders enter or leave but in an unregulated manner. And at last selectively-permeable membranes can be described as a house that has Alexa-controlled doors and windows. They operate as you command and want.

diffusion vs osmosis

Figure:An interactive image showing the difference between diffusion (freely permeable membrane) and osmosis (semi-permeable membrane). It is available in the Osmosis and Diffusion simulation from Labster. The simulation is available for High School and University/College courses.

We feel such examples can clarify a lot of intricate topics for your students. A similar analogous lesson about IV/intravenous solutions is demonstrated in the Osmosis and Diffusion simulation from Labster. Knitting short interesting analogies around scientific topics help in a more lucid delivery of concepts in classroom teaching. And we highly recommend using them in your next class.

3. Relate it to the commercial and industrial applications

When a theoretical concept is applied to a device, commodity, technology, or appliance, students are more persuaded to learn about it. You can quote a multitude of examples where diffusion and osmosis play an instrumental role. We are providing a few of them for you to begin with. 

1. ORS (Oral Rehydration Solution): Although the sodium ions are transported in an active (ATP-driven) mechanism, the movement of water is passive via diffusion. Rehydrating solutions are used to counter severe dehydration in arid areas, severe diarrhea, blood loss conditions, etc.

2. RO Water Purification Systems: RO systems are common household appliances that purify tap water and make it ingestible. It works on the principle of reverse osmosis.

There are several other examples that you can quote to gather the active engagement of your students in the class.

4. Clarify the chemistry concepts

It is of prime importance that your students can follow the meaning of concentration gradients, solute-solvent-solution concepts, and other basic chemistry concepts. This can ease the journey of learning the biochemistry and physiology of living organisms. You can use video graphical tools from the open source or the Osmosis and Diffusion simulation from Labster. When demonstrated in the form of graphics and animations, the directionality of the flow of solutes and solvents is easier to understand. Teaching fundamental concentration calculations and unit conversions can also come in handy.

Osmosis Virtual Science Lab

Figure: An image showing calculations involved in the concentration changes (% change). It is available in the Osmosis and Diffusion simulation from Labster. The simulation is available for High School and University/College courses.

5. Use virtual lab simulations

Osmosis and diffusion are challenging theoretical concepts to teach, therefore, we at Labster have a solution for you. You can utilize Labster's Osmosis and Diffusion simulation in your next class to close the gaps in the available teaching resources and address the lack of visually engaging video graphical possibilities in the educational space.

Your lecture delivery and lab management sessions will be made easier by Labster's virtual laboratory simulations. Because students have access to visual alternatives, you may make more insightful points. We offer the help of our interactive simulations and gamification components. Our virtual learning platform uses this method of interactive, immersive instruction to strengthen the fundamental concepts for future scientists in the making.  

You can learn more about the Osmosis and Diffusion simulation from Labster here or get in touch to find out how you can start using virtual labs with your students.

osmosis and diffusion sim

sFigure: An image showing the different available choices of IV solutions, one being hypotonic. It is available in the Osmosis and Diffusion simulation from Labster. The simulation is available for High School and University/College courses.

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