What is diffusion & what are factors that influence diffusion? Diffusion is everywhere around us. Learn more about it & its various types like passive diffusion

1. Diffusion: Definition, Examples, Types, and Factors
Affecting It
Austin February 23, 2022 no Comments
What is Diffusion?
Diffusion can be defined as the procedure involving the net movement of
anything like energy, ions, atoms, and molecules normally from a place with
a higher concentration to a place with a lower concentration. The driving
force behind diffusion is a gradient in chemical potential or Gibbs free
energy. Contrary to popular belief, the uphill diffusi on of something from
a place with a lower concentration to a place with a higher concentration
is possible (for instance, in spinodal decomposition).
Diffusion is studied in a variety of fields from economics, sociology, and
biology, to chemistry, physics (particle diffusion), and finance (the diffusion
of price values, people, and ideas). Despite the little bit of difference in the
way they are studied, the central idea of diffusion remains the same i.e.,

2. something undergoing diffusion starts from a place with a higher
concentration of that said thing under discussion.
A Detailed Example Of Diffusion
Start by collecting some water in a container or a beaker, add a few crystals
of copper sulfate to it at one specific region and leave the newly formed
concoction like that for some time. Do not disturb it all. Check on the
beaker after some time and you will be surprised to see that there will be
a uniformly colored solution in that beaker. In this example, you will see
that both the crystals of copper sulfate and water diffuse independently.
Therefore, you can conclude that a solute in a solution moves from a higher
concentration to a lower concentration.
Is There Any Significance of Diffusion?
Yes, there is a great significance of diffusion, it is a part of ma ny important
life processes. Since it is the net movement of solutions, ions, particles,
molecules, it plays a vital role in the movement of the particles during the
metabolic processes happening in the cells.
Other than that, diffusion is significant for the following reasons:
• Diffusion is also involved in the process of respiration as it helps in
diffusing the CO2 (Carbon dioxide) out into the blood through the
cell membrane.
• The process can also be seen in plant cells as the water present in
the soil enters the plant with the help of diffusion through their
root hair cells.
• The generation of electrical charge is also a product of diffusion
that is responsible for the movement of ions across the neurons
that are meant to generate the electrical charge.

3. What Are The Types of Diffusion?
Let’s move on to the types of diffusion that occur in different materials:
1. Simple Diffusion
Simple diffusion can be defined as just the movement of molecules on the
path of their concentration gradient and this happens without the direct
involvement of any other substance or molecules. Simple diffusion can
either be the spreading of different sub stances via a medium or the
movement of a molecule through a membrane.
Simple diffusion is super important in numerous physical phenomena,
chemical reactions, geological events, and can even impact global weather
patterns. When it comes to biological systems, simple diffusion occurs
through a semipermeable membrane which is made up of lipid bilayer and
has openings and pores that allow the easy passage of specific molecules.
2. Facilitated Diffusion
However, facilitated diffusion, as its name shows, needs a nother molecule
which is known as the facilitator to diffuse across something. This kind of
diffusion is needed for the movement of polar or large across a
hydrophobic lipid bilayer. Another important role of facilitated diffusion is
in biochemical processes occurring in every cell as communication occurs
between different subcellular organelles.
What is the Disk Diffusion Method?
The disk diffusion method also commonly known as the DDM can be
described as an agar diffusion method (also known as ADM). The r eason for
this is that the plant extract that needs to be tested diffuses from its
reservoir via the ADM medium seeded with the concerned test

4. microorganism. The reservoir used is normally a filter paper disk that you
place on the top of an agar surface. An inhibition zone forms around the
filter paper following incubation oif the plant extracts under testing are
microbiologically active. You can calculate the antimicrobial potency of
those plant extracts or the isolated compounds you want to test by using
the diameter of the inhibition zone.
However, one thing to keep in mind is that the disk diffusion method is not
a suitable way of experimentation for lipophilic extracts. The reason for
this is that the diffusion of the water -insoluble EO (an example of lipophilic
extracts) and its compounds from a filter paper disk into an agar medium
is not adequate. And, as a result, the EOs provide negative results or very
small inhibition zones are formed with the Disk Diffusion Method as
compared to other tests.
What Are Some Examples of Diffusion?
Let’s look at some diffusion in liquids examples along with daily life, human
body, and nature:
Examples of Diffusion in Daily Life
As mentioned above, diffusion happens everywhere, it is a universal
physical phenomenon. Let’s look at some of its notable examples in our
daily lives:
1. Perfume
When you spray perfume, cigarette smoke, air freshener, or any type of
strongly scented substance in one part of a room, it slowly reaches other
parts of that room because of diffusion.
2. Balloons
Have you ever wondered why helium balloons slowly come back to the
ground? The reason for that is the slow diffusion of helium from a region

5. rich in helium (inside the balloon) to a region that is not that concentrated
in helium (the outside air).
3. Food Coloring
When you pour a drop of food coloring in water, it spreads throughout the
container via diffusion as the molecules gradually spread evenly through
water, thus forming one particular shade.
4. Soda
Have you ever noticed that sodas lose their fizz a fter some time? It happens
because of diffusion because the air has a lower concentration of the fizzy
CO2 that is present in the soda. As a result, the molecules of the bubbly
CO2 leave the soda and disperse into the air.
Examples of Diffusion in The Human Body
As we have established above, diffusion runs the human body as it is
responsible for all the important biochemical and biological processes
happening in the body.
If diffusion stopped happening in the human body, life would stop as well.
Let’s look at some examples of diffusion happening inside the human body:
1. Breathing
The most important process taking place in the human body is directly
related to diffusion. When we take a deep breath, the oxygen only enters
our bloodstream when the Oxygen (O2) molecules diffuse into
deoxygenated blood. The process of breathing in and breathing out is a
mechanical action, however, the oxygen only enters the bloodstream via
diffusion.
2. Calcium
We do not need calcium just for our bones, we also need it for other
physical functions, movement of muscles, and sending nerve signals. When
there is inadequate calcium in the bloodstream, the thyroid gland present

6. in the human body secretes a chemical that causes our bones to release
calcium. The calcium then diffuses int o the blood and solves the issue.
3. Kidneys
Even kidneys display diffusion as they filter dangerous chemicals and
substances from the bloodstream via microscopic tubes known as
nephrons. The nephrons separate the blood from waste substances, toxins,
and chemicals, reabsorb the water and important nutrients back in the
blood via diffusion.
4. Liver
The liver synthesizes proteins in the human body and in the process of that
synthesis it also produces a potentially harmful waste product known as
urea. Thankfully, with the help of diffusion, the urea diffuses into our
bloodstream just upstream of our kidneys and is then filtered out.
Examples of Diffusion in Nature
Diffusion is truly a universal physical phenomenon, and so many natural
processes depend on it.
1. Air Pollution
Air possesses approximately 21% oxygen, 1% argon, 78% nitrogen, and
0.04% carbon dioxide along with trace amounts of other gasses in its
natural state. Many mechanical, agricultural, and industrial processes
produce waste stuff as a by-product that diffuses into the air and pollutes
it.
2. Crystals
Crystals naturally have vacant spaces in their atomic structure through
which the atoms can diffuse. When you compress a crystal, the atoms go
into those tiny vacancies, as a result, they create n ew vacancies and this
changes the atomic structure of the crystal.
3. Intracellular Motion

7. Intracellular motion is the motion that happens inside one side instead of
between multiple cells. Diffusion occurs when a new chemical or substance
enters the cytosol of a cell. The cytosol is fluid and is a part of a cell’s
insides. When a new particle, chemical, or molecule enters the cell, it
diffuses uniformly through the cytosol.
4. Leaves
Leaves also make use of diffusion during the night. Plants breathe in
Carbon Dioxide (CO2) during the day and, as a result, breathe out oxygen
via osmosis (it opens and closes the stomata). However, during nighttime,
the stomata remain open so osmosis is not required and Carbon Dioxide
(CO2) enters the plant via diffusion.
Factors that Influence Diffusion
Many factors can influence the process of diffusion and disrup t it even.
Some of those factors include particle size, temperature, steepness of the
concentration gradient, and area of interaction. These factors, on their
own, and collectively can change the extent, intensity, and rate of diffusion.
1. Temperature
In every system, the molecules move with a specific amount of kinetic
energy which is normally not directed in any certain manner and if you look
at it, it might appear totally random. When these moving molecules collide
with each other, the direction in whic h they are moving changes. With the
change in their direction, their velocity and momentum also change.
Let’s take the example of a block of dry ice. Dry ice is basically just Carbon
Dioxide in solid form, and let’s place this block of dry ice inside a con tainer.
The molecules of carbon dioxide present in the center of the block will
majorly just mostly collide with one another and they will remain inside the
solid mass. However, the molecules that are located in the periphery, the
rapidly moving molecules present in the air will affect their movement as

8. well, and, as a result, the peripheral molecules will begin to diffuse into the
air. This process results in the formation of a concentration gradient, in
which the concentration of carbon dioxide is slowly reduced with distance
from the block of dry ice.
What happens in such scenarios is that the kinetic energy of all molecules
present in a system increases as the temperature increases. As a result, the
rate at which solute and solvent molecules move increas es and their
collisions also increase. In other words, the block of dry ice (or even regular
ice) will undergo evaporation quicker when it is warm outside because the
molecule will move with more energy and will quickly escape the solid -
state.
2. Area of Interaction
Let’s continue with the example discussed above of the block of dry ice.
Imagine if you break that block of dry ice into a lot of pieces, the area of
that ice that interacts with the atmosphere surrounding it also increases
immediately. Consequently, the number of molecules of Carbon Dioxide
that only collide with other molecules of the gas within dry ice decreases,
and the rate with which they diffuse into the air increases.
You can understand the area of interaction and its influence on the pro cess
of diffusion even better if the gas you are experimenting with has color.
For example, if you sublimate iodine over a hot stove or bunsen burner,
you will notice that purple fumes are formed when you heat it and mix it
with the air. If you carry out the sublimation in a narrow crucible, you will
notice that the fumes will gradually diffuse towards the mouth of that
narrow crucible and will disappear rapidly. The reason behind this is that
when the surface area is smaller, the rate of diffusion of a sub stance
remains low.

9. You can also observe this when you mix two liquid reactants. You will notice
that as you stir them the area of interaction of the chemicals will increase
and it will allow them to diffuse more quickly.
3. Steepness of The Concentration Gradient
The process of diffusion is mainly powered by the probability of molecules.
For instance, when you diffuse iodine gas, if you place the narrow crucible
in another closed container and heat the iodine crystals for a long time, the
rate at which the purple gas disappears (as discussed above) will decrease.
This reduction in its disappearance is because, as time goes on, the larger
container, in which the narrow crucible is enclosed, starts to have enough
iodine gas that some of that gas will start go ing back to the narrow crucible.
4. Particle Size
No matter what the temperature, the rate at which a smaller particle
diffuses will always be more rapid than the rate at which a larger -sized
molecule diffuses. This is influenced by both the surface areas and the mass
of the molecule because a heavier molecule with a larger mass and larger
surface area will diffuse slowly. On the other hand, a lighter molecule with
a smaller mass and smaller surface area will diffuse more quickly.
For instance, if we look at oxygen gas; its molecules will undergo diffusion
more quickly as compared to the molecules of carbon dioxide. However, if
we compare both of them to iodine gas, then both Carbon Dioxide and
Oxygen will diffuse more quickly.
What is Identity Diffusion?
The concept of identity diffusion is not directly related to the diffusion we
are discussing, however, many people still mistake it for a type of diffusion
because of its name.

10. Identity diffusion is a phenomenon in which people who have this said
condition have not committed to a specific path to attain their future and
are not even making any effort to come up with a plan. This included both
occupational and ideological futures.
Normally, people undergo identity diffusion during their adolescence
because it is a time when people are still working on their identities, but it
can pass on to adulthood.
What is Passive Diffusion?
Passive diffusion can be defined as the by which molecules diffuse from a
place with a higher concentration to a place with a lower concentration and
it is vital for the passage of important drugs through membranes. For
instance, if we talk about lipid-soluble drugs, they can penetrate lipid
membranes without any difficulty.
Conclusion
And there you have a complete rundown of diffusion, its types, its
examples, and the factors that can influence the rate of diffusion. If you
want to understand the concept of diffusion better, we recommend you ask
your physics tutor to explain its types and examples with real -life examples.
We hope we were able to clear your concept of diffusion. Best of luck!
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