Investigating Diffusion Rates in Different Concentrations: Biology Lab

This assignment is a biology lab report that investigates the process of diffusion in living organisms. The experiment aims to determine how the rate of diffusion varies with different concentrations of hydrochloric acid (HCl) in agar. The methodology involves preparing agar blocks and exposing them to HCl solutions of varying molarities (0.1M, 0.5M, and 1M). Observations include the time taken for the agar to change color, indicating the diffusion of HCl. The report also explores factors affecting diffusion, such as temperature, surface area, concentration gradient, and particle mass. The results demonstrate that diffusion rates are influenced by concentration, with higher concentrations leading to faster diffusion. The report also discusses the importance of diffusion in biological processes, including its role in transporting essential components within cells and plants.

Diffusion in living
organism

Table of Contents
Aim – To determine if rate of diffusion vary in higher concentrations. ........................................3
INTRODUCTION...........................................................................................................................3
MATERIAL-...............................................................................................................................3
METHOD-..................................................................................................................................3
Observation.................................................................................................................................4
Experiment 2....................................................................................................................................5
Method........................................................................................................................................5
Observation.................................................................................................................................5
Result and conclusion.................................................................................................................6
Factors affects Diffusion..................................................................................................................6
TEMPERATURE........................................................................................................................6
SURFACE AREA ......................................................................................................................6
CONCENTRATION GRADIENT ............................................................................................7
MASS OF PARTICLE...............................................................................................................7
SOLVENT PROPERTIES .........................................................................................................7
Importance of Diffusion .............................................................................................................8
CONCLUSION................................................................................................................................8
REFRENCES...................................................................................................................................8

Aim – To determine if rate of diffusion vary in higher concentrations.
Experiment 1
INTRODUCTION
Diffusion is termed as physical process, that conclude the net movement of molecules
from higher concentration to lower concentration. It depends on the substance and medium in
which it takes place. The substance diffuses can be solid, liquid or gas. Similarly, the medium in
which it occur can be in one of three physical states. Diffusion involves the movement molecules
as well as concentration gradient.
Rate of diffusion is directly proportional to the medium and substance in which the
process take place. As this process does not involve complex and high energy molecule. The rate
of diffusion process also rely on interaction between medium and substance. For example: A
strong fragrance of ammonia gas disperse in a atmosphere rapidly, the nitrogen molecules are
loosely packed this property helps nitrogen or gas substances to escape quickly into atmosphere.
Similarly, every physical state debits its own diffusing property. Solid substances generally given
away slow rate. Transportation is a important and natural process which occurs in higher plants
as it helps to obtain organic and inorganic material for basic functions of cells as well as tissue.
In this experiment, the demonstration of discolouration in agar due to diffusion. In this
experiment, rate of diffusion in different molarities observed. As the diffusion debits different
properties at different concentration gradient (Xu and et.al, 2019) . In this experiment hypothesis
test was taken in order to get accurate and meaningful result and to observation displacement of
molecules from higher concentration to lower concentration.
MATERIAL-
3 beakers, block of agar stained pink with the indicator phenolphthalein, HCl with
different concentration(0.1M, 0.5M and 1M) in a beaker respectively , a ruler, a stopwatch, white
tile, block of agar, Blade, Obstetrical forceps. Petri dish
METHOD-
The first step to carry out this experiment was cutting out three agar cubes of equal size
of 1cm by sharp blade and subjected in a Petri dish with a help of Forceps. Meanwhile, three
beakers were filled with concentrated HCL solution which had different molarity (0.1M, 0.5M
and 1M) receptively in each beakers. Slices of agar submerged into prepared solution carefully

by the help of and the slices were given time to react with solution with different molarities and
it was allowed to kept in open air in order to adapt room temperature. The time was observed by
putting stopwatch beside them.
Observation
It was observed that the colour of indicator changed pink to colourless, as it was pink at
initial due to presence of NaOH, it changed colourless because HCL molecules diffuses into agar
block in a given time.
Graph showing rate of diffusion
Surface area covered Time taken for discolouration
0.8cm 8 min 525s
1.30cm 20 min 20s
1.70cm 42 min 10s
Observation table

Experiment 2
Method
In this experiment, cubes were cut into length of 0.8 cm, 1.30 cm and 1.70cm with help
of blade and kept in a Petri dish which was already filled with distilled water. On the another
hand three beakers were prepared which contained 50ml of concentrated HCL of 1M. The slices
were submerged into respective beakers and subjected into air in order to stable molecules as
well as indicator to react and were started to observe time by stopwatch.
Observation
It was observed that the color of each cube become colourless, due to presence of NaOH
in a indicator. As graph shows the rate of diffusion increased by interaction between molecules.
Rate of diffusion at High Concentration

Surface area Time taken for discolouration
0.8cm 8 min 52 sec
1.30cm 20 min 20 sec
1.70cm 42 min 10 sec
Observation table
Result and conclusion
In experiment it has determined that rate of diffusion vary in high and low moralities.
There can be numerous factor which effect the rate of transpiration. Hence, this procedure leads
with interactions molecules which can vary state of matter to matter. For example, in solid the
rate of diffusion may take velocity to cover surface area in a medium. There are some common
factors as follows which can affect diffusion, they are as follows:
Factors affects Diffusion
TEMPERATURE
Temperature is essential element for diffusion as the property of molecules debits their
own reactants property. If the temperature is higher, molecules or particles inhibit more kinetic
energy which will lead them to move fast and get mixed up simultaneously.
SURFACE AREA
Surface area of cell or any medium can affect diffusion rate as smaller surface area, the
slow rate of diffusion. It is due movement of molecules, If molecules do not get enough space so
the diffusion rate will occur slow. Similarly, the greater surface area exhibit the faster rate of
diffusion.

CONCENTRATION GRADIENT
Difference in concentration is termed as concentration gradient. In diffusion process,
practicals moves higher concentration to lower concentration. Hence, as the greater
concentration give way faster rate of diffusion as compared to diluted ones or lesser ones.
MASS OF PARTICLE
The mass of particle may create variation in rate of diffusion as well. Heavy particle will
move slowly in order to complete process. And on the other hand smaller particle debits faster
because they can move faster. As the key, the displacement of particles is paramount in
observing if diffusion is occurring slow or fast.
SOLVENT PROPERTIES
There are two basic factors of solvent properties which can affect the procedure.
Viscosity and density can fairly and greatly affect. For an example, if the solvent or medium
which is provided to particle dense or viscous in nature so the particle will struggle more and
take more time to accomplish the process. So the rate of diffusion will be low. As studies
concluded that small ion can move through viscous solution faster.
Diffusion theory explains in terms that analysation of movement through materials for
example- water or any other scientific or biological fluid. First, theory evaluation, from
originated and there are various connection mechanistic materialistic philosophy of middle 12th
century biology is determined with theories for example transportation of oxygen within air and
mammalian tissues nature of intermediary metabolism etc.
Limitations
As the diffusion is limited in crossing and curving areas. Diffusion is a process which is
one way direction. There is huge risk of contamination. As the process takes place through cell
membrane or in the particle perhaps there is huge risk getting a virus or bacterial action (Li and
et.al, 2019). In this experiment the room temperature should be normal otherwise rate of
diffusion varies.
Importance of Diffusion
Diffusion is important as it help to attain essential components to cell which require to
grow and obtain energy. Diffusion is considered as main pathway of transportation in a plants. It

helps in gaseous exchange through stomata. It also play significant role in gaseous exchange
through stomata, transpiration, aroma of flowers also due to diffusion, absorption of ions,
translocation, provide moisture in internal tissues etc (Molina-Garcia and et.al, 2018) .
Transportation process is carried out by diffusion. In bacterium, diffusion helps in exchange of
fluids components and major nutrient through diffusion in cell membrane.
CONCLUSION
As it observed process of diffusion usually work a lot of time and it is proved that it is a
efficient, time taking, essential and delicate process. There are numerous factor from which
diffusion its not compromised which are size of particle, medium, permeability in which
diffusion is carried out, temperature etc. it is process that can happen instantly but may take time
to evenly disperse of chemicals into the given area .

REFRENCES
Book and Journals
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biomolecular interactions and biochemical networks in living cells. Journal of proteome
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Mailfert, et.al, 2020. Spot Variation Fluorescence Correlation Spectroscopy for Analysis of
Molecular Diffusion at the Plasma Membrane of Living Cells. Journal of Visualized
Experiments: Jove, (165).
Molina-Garcia, D., and et.al, 2018. Crossover from anomalous to normal diffusion: truncated
power-law noise correlations and applications to dynamics in lipid bilayers. New Journal
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Peach, C.J., Kilpatrick, L.E., Friedman-Ohana, 2018. Real-time ligand binding of fluorescent
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Xu, and et.al, 2019. Sedimentation study of bioink containing living cells. Journal of Applied
Physics, 125(11), p.114901.