Day: Date: Class: 5 years
Length of class: 80 mins Subject:Biology
Topic: Diffusion and Osmosis
th
Previous Knowledge and Experience:
Students will be familiar with diffusion from the
chemistry section of the Junior Cycle science syllabus.
Students should be able to define diffusion from their
knowledge of the topic. They may have seen the effects
of diffusion in a liquid using water and potassium
manganate crystals. Students would encounter
diffusion in their everyday lives, even if they do not
recognise it, for example when they are making a cup
of tea as the tea diffuses into the hot water. I would
expect that students have not come across the term
osmosis as it is not on the Junior Cycle syllabus.
Although they have not come across this term, they
know the effects of osmosis from the Junior Cycle.
Students know that plants uptake water through the
roots, this is done through the process of osmosis. Also,
using their knowledge of Junior Cycle history, the
students know that sailors, for example Christopher
Columbus, preserved their food in salt.
Aims:
To overcome students misconceptions in relation
to diffusion and osmosis and to develop their
understanding of accurate concepts within the
topic
Learning Outcomes:
Students should be able to recognise their
misconceptions of the topic
Students should overcome their misconceptions
and recognise the accurate scientific concepts in
relation to diffusion and osmosis
Students should appreciate the everyday relevance
of diffusion and osmosis
Students should be able to differentiate between
diffusion and osmosis
Students should be able to discuss the processes
involved in diffusion and osmosis and give
everyday examples of the two
Students should be able to demonstrate the effects
of osmosis using everyday objects
Subject Matter:
Students will learn about selectively permeable
membranes and everyday objects that have this
membrane, for example cellophane and visking tubing.
Students will learn about the process of diffusion and
that it is the spreading of molecules from a region of
high concentration to a region of low concentration.
Students will learn about the process of osmosis and
that it is the movement of water molecules across a
semi-permeable membrane from a region of high water
concentration to a region of low water concentration.
Students will also learn about the everyday examples of
diffusion and osmosis.
Resources:
The resources I will use in this lesson will cater for a
range of different learners, for example, visual,
auditory, kinaesthetic and pen and paper. The resources
I will use in this lesson include: Concept maps, posters,
markers, powerpoint, video, eggs, glass beakers,
vinegar, spoon, corn syrup, activity sheet, flash cards.
Assessment:
At the beginning of the lesson I will assess the
student’s prior knowledge by asking them to construct
a concept map of diffusion and osmosis. This will
allow me to recognise any misconceptions that the
students may have. This will also act as a tool for
assessment for learning for the students, as they will
realise the level of knowledge that they have on the
topic. I will also assess the students throughout the
lesson by observation and teacher questioning. I will
use a series of higher and lower order questioning,
using Bloom’s taxonomy. This will allow me to cater
for diversity in the classroom as I will aim the lower
cognitive questions to the lower ability students, and
the more challenging questions at the higher ability
students. Question stems from the lower scale include
list, define etc. and from the higher scale include
compare and contrast. At the end of the lesson, students
will be assessed through the flash card game. Each
student will receive a card with a word term on it from
diffusion and osmosis. The student will stand at the top
of the class and the other students will give them hints
as to what the word is. This will not only assess the
student at the top of the class but all the students in the
classroom.
Classroom management:
Students will make sure their bags are places
underneath their desks and out of the walkway.
Students will be grouped into pairs for group work, in
order to cater for crowd management. There will be a
clear set of instructions for the experiment on the
whiteboard while the students are completing it.
Safety:
Students will use caution when doing the experiment,
being careful not to break the glass beakers. Students
will notify the teacher in the case of any breakage or
spillage of liquid and will not attempt to clean it
themselves. Students will stay at their desk unless
asked to move. One student from each group will come
to the top of the class to collect equipment for the
experiment, to relieve congestion.
Time Pupil Activity Teacher Activity References
Common Misconceptions:
• Osmosis and diffusion are fundamentally different processes.
• Osmotic equilibrium cannot be reached unless solute concentrations equalize
across the membrane.
• Water molecules cease movement at osmotic equilibrium.
• Diffusion and osmosis do not occur across nonliving membranes.
• The rate of osmosis is constant and does not vary with a difference in solute
concentrations between two solutions separated by a selectively permeable
membrane
Set Induction:
Students will construct a
The teacher will go The concept map will
concept map on the topic of to each student and allow the teacher to
Diffusion and Osmosis. A
look at their concept recognise any
simple reminder of how to
map, this will act as a misconceptions that the
construct a concept map will tool to recognise any students may have, it
be displayed on the board.
misconceptions that will also be an
Students will work
the students may
assessment for learning
individually.
have in relation to
tool for the students.
the topic.
“The maps provide a
representation of
Students will work in pairs
Teacher will divide knowledge and hence
and using the poster and
students into pairs. can be used to infer
markers that the teacher has Strategically placing accuracy
given out, they will work
students together, for and depth of
together, putting their concept example a higher
knowledge.” (Broggy
maps together to make a new ability student with a et al, 2008)
concept map.
lower ability student.
Development:
The teacher will
reiterate the general
lab rules to the
students (these will
One student from each group be on the board) and
will come to the top of the
divide the students
class and collect the needed into pairs.
equipment and bring it back to The teacher will tell
their desk.
students how to
complete the
experiment, the
Students will complete the
instructions will be
“egg experiment”. The
left on the board for
students will use an egg that the students to see
has been soaked in vinegar for throughout the
24 hours. The students will be experiment.
able to see the semi-permeable
membrane as the vinegar
dissolves the calcium in the The teacher will
shell but leaves the membrane circulate the
intact. The students will pour classroom, going to
corn syrup into a glass beaker each group to make
and place the egg inside. The sure they understand
students will put their glass
what they are doing.
beakers to the top of the class
Each student will put on lab
coats and gloves.
One student from each
group will collect
equipment, to reduce
congestion and risk of
accidents in the
classroom. This also
manages crowd
control.
Engage: This
experiment
demonstrates osmosis
with everyday objects
that the students would
have at home. This will
interest the students in
the topic and show that
it is an everyday
and clean their desks. The
beakers will be left for 20
minutes.
Teacher will monitor process and not so
the students as they abstract.
clean up, making
sure that there is no
mess left behind.
The students will answer
Teacher will ask a
questions on what they think series of questions to
will happen to the egg using probe students to
their prior knowledge of
apply their
osmosis.
knowledge of
Questions:
osmosis and predict
-What is osmosis?
the outcome of the
-Why did we use an egg?
results.
-Why was it soaked in
vinegar?
-What would happen if it was
soaked in water?
- Why was it important that
the semi-permeable membrane
was left intact?
- Why did we use corn syrup?
-Explain what you think will
happen?
-What would happen if we
used water?
-Would the movement of
water still occur if the egg was
placed in water?
Students will watch a video
clip explaining simply what is Teacher will explain
involved in the processes off the processes of
diffusion and osmosis.
diffusion and
osmosis, and what a
Questions:
semi-permeable
-Why is osmosis important to membrane is.
humans?
-What would happen to
Teacher will ask
humans if osmosis and
students questions,
diffusion didn’t happen?
using higher and
-Compare and contrast the
lower order
processes of diffusion and
questioning.
osmosis
Students will collect their
experiments and bring them
back to their desks.
Students will examine the
results in their groups and
come up with an explanation
of what has happened and a
general conclusion.
Using a series of higher
and lower cognative
questioning to cater for
differentiation in the
classroom. “There are
a large number of
differences between
pupils and between
groups of pupils
that may influence
teaching and
learning” (Arthur et
al, 2006)
Explain: Teacher
verbally explain these
concepts to the
students, and they will
watch a short video
clip. This caters for
visual and auditory
learners. This
explanation will
hopefully remove any
misconceptions that the
students may have.
Teacher will go to
each group asking
them what they think Elaborate:
has happened and
Students will apply
why. The teacher will what they have learned
guide the students to during the class to
the right conclusion. explain the results of
the experiment.
Conclusion:
Students will play the flash
Evaluate:The students
card game. Students will be Teacher will be able will be assessed by the
asked to stand at the front of to assess the student’s teacher on what they
the class, and hold up a flash knowledge of the
have learned in the
card with a term from what we topic from this game. lesson and to assess if
have done in the lesson. The All students will be they have replaced the
other students in the class
assessed as students misconceptions with
must help the student guess
will have to give the accurate conceptions.
what the word is, without
chosen student
“Assessment thus
saying the actual word.
consists of techniques
you can use
Students will complete an
Teacher will hand
to monitor pupils’
activity sheet for homework. each student an
progress in terms of
activity sheet
specific learning
outcomes” (Kyriacou,
2007)
Reference List:
• Arthur, J., Grainger, T. and Wray, D. (eds) (2006).
Learning to Teach in the Primary School. London:
Routledge.
• Broggy, J.,McClelland,G. (2008). Undergraduate
Students’ Attitudes Towards Physics after a
Concept Mapping Experience. Concept Mapping:
Connecting Educators.
• Kyriacou, C. (2007). Essential Teaching Skills.
Cheltenham: Nelson Thornes Ltd.