EDSE 452 Nature of Science Lesson Plan Assignment
Grade 10, Unit C: Cycling of Matter in Living Systems
Bill McKenna (ID# 1037302)
Program of Studies Learning Outcomes:
Describe the function of cell organelles and structures in a cell, in terms of life processes,
and use models to explain these processes and their applications
- Use models to explain and visualize complex processes like diffusion and osmosis,
endo- and exocytosis, and the role of cell membrane in these processes
- Describe the role of the cell membrane in maintaining equilibrium while
exchanging matter
- Describe how knowledge about semi-permeable membranes, diffusion and osmosis
is applied in various contexts
Students will ask questions about observed relationships, and plan investigations of
questions, ideas, problems and issues
- State a prediction and a hypothesis based on available evidence and background
information.
Lesson Objectives: Student should be able to:
- define the difference between Passive and Active Transport
- distinguish between the different types of Passive Transport
- distinguish between the different types of Active Transport
- see how scientific understanding has led to technological human benefits
- use their skills of scientific inquiry to make predictions in the Transport Lab
Required Materials: Video projector and computer, rubber glovers, safety goggles, lab
apron, 500ml beaker, tap water (300ml), 1 - 10cm dialysis tube, 2 elastics, paper towels,
starch solution, plastic spoon, iodine solution (Lugol’s).
Safety Considerations: Teacher to follow safety precautions by wearing lab coat, safety
goggles, and rubber gloves. We are only using a few drops of the iodine solution, but it
can stain clothing and skin. Discuss the proper disposal of the iodine solution. Wear
gloves when handling the dialysis tubing as it is stored in a poisonous substance, sodium
azide (which washes off when soaked in the water).
Student Prerequisites: The students would have been previously exposed to organisms,
cells, system organs, and tissues (Grade 8 Science, Unit B: Cells and Systems).
This lesson is at the end of the sub-chapter on Transport across the Cell Membrane. With
a quick review the students should be able to easily hypothesis and investigate what will
occur in the lab experiment.
The students have already have completed a lesson on proper lab safety.
Introduction: (5 min)
Outline of Today’s lesson
-
A few quick questions to get the students thinking (See Teacher Notes)
-
Hook Activity. Investigate the misconceptions of water transport (See Teacher
Notes) through a lab experiment.
-
A review of Passive Transport: Diffusion
-
New information. Passive Transport: Osmosis
-
Lab Conclusion
Teacher review of prior knowledge through some questions posted on the Power Point.
(Questions attached)
Lab Experiment: (15 min) Transport Lab.
Lab Procedure on handout.
The students work in their pre-assigned lab table groups. The assigned seating was
planned to allow a mix of multi-level learners at each table.
Body of Lesson: (20 min)
Outline of Topics. Notes attached.
-
Review of Passive Transport: Diffusion
-
New material. Passive Transport: Osmosis
Allow student questioning and investigatory discussions as they arise.
Conclusion: (10 min)
Conclude the Transport lab
- As a group they are to complete 3 questions on the back of the data sheet and
submit at the end of the class. The lab will be collected for assessment for
learning purposes.
- The teacher is to use this opportunity to correct any misconceptions of passive
transport. The teacher should have an open discussion soliciting student answers
from these questions. Building on new student knowledge the teacher guides the
construction of student knowledge.
Hand out Summary notes from today’s class.
Introduction of the next lesson: Facilitated Diffusion
Notes: (Teacher notes are italicized)
Focusing Questions:
While the students are conducting the lab procedures ask them predicting questions
about transport across a semi-permeable membrane. Will there be any net movement of
water, starch or iodine across the dialysis membrane (semi-permeable membrane)? Why
or why not? Have the students write at least one predicting statement on their lab sheet.
Fisher (1997) lists 3 general misconceptions involving transport across a semipermeable membrane:
Misconception #1: Students often base their predictions regarding the overall direction
of osmosis on the concentration of the solute (e.g., 70% sugar, 20% sugar)
Correction #1: The concentration of water is the factor that determines the overall
direction of osmosis, and H2O concentrations are approximately inversely proportional
to solute concentrations (e.g., 30% H2O, 80% H2O).
Misconception #2: Common solute molecules such as salt and sugar will diffuse through
a semi-permeable membrane
Correction #2: Only water and other small, neutral molecules (such as oxygen and
carbon dioxide) can diffuse across a semi-permeable membrane; sugar molecules and
salt ions are too large and carry too much charge.
Misconception #3: Osmosis will continue until equilibrium is reached, with equal
concentrations of solute on both sides of the semi-permeable membrane.
Correction #3: Osmosis often fails to reach equilibrium levels because of other factors,
such as pressure inside a plant cell or atmospheric pressure on a column of water
Quick review of Diffusion from previous lesson
-
Use the slides from the Power Point for reference
New Material. (Power Point Presentation. Paper copy attached)
PASSIVE TRANSPORT: Osmosis
-
The diffusion of water across a membrane is called osmosis. Most of the
molecules that fill and surround cells are water (H2O)
-
Show the video of Diffusion of water
-
Water molecules move from areas of high concentration of water to areas of low
concentration of water across a semi-permeable membrane.
-
Show the visual of Osmosis
-
If one solution has a high concentration of H2O and a low concentration of solutes
relative to another solution it is called HYPOTONIC. (Show the Hypotonic
Visual)
-
Also refer to Hypertonic and Isotonic. Show the accompanying visuals.
-
Show the visual of the Water Movement. Explanation:
A. Add sucrose, now the concentration of water inside the cell is higher.
B. The water moves out of the cell to balance the concentration
C. Add distilled water, now the concentration of water outside the cell is
higher.
D. The water moves into the cell to balance the concentration
-
In plant cells, the cell contents will lose water, shrivel and pull away from the cell
wall (plasmolysis).
-
Other important terms: Crenated, Turgid, Flaccid
Membranes at work. Show power point slides to demonstrate how science and
technology are influenced and supported by society and have influenced, and been
influenced by, historical development and societal needs. This concept is outlined in the
Program of Study (2005).
-
Water Purification (Reverse Osmosis)
-
Kidney Dialysis (Diffusion)
-
Controlled delivery of medication (Liposomes)
Assessment for learning questions: TRUE or FALSE? The following are just quick
feedback questions at the end of the lecture: The students can vote by a show of hands.
Answers: 1. True, 2. False, 3. False, 4. True
Question: FILL IN THE BLANKS? The students can vote by a show of hands.
Answer: C
Justification:
This lesson was designed to include different pedagogical methods. The lesson
includes a review of previous knowledge. This was elicited through open discussion with
the students, lecture format, and visual text. The lesson also took advantage of kinesthetic
learning, with a great hands-on lab. The lab worked well to link the students
understanding of the nature of science. Science follows scientific methods with common
characteristics, but no single path leads to certainty (Colburn, 2004, p.32). As Fisher
(1997) notes, there are 3 general misconceptions regarding passive transport across a
semi-permeable membrane. I wanted to make sure that I was explicit with my lesson.
Reeves, C, Chessin, D, & Chambless, M. (2007) claim that one of the most effective
methods for enhancing students’ understanding of the nature of science was through the
“explicit” approach, where the instructor provides a clear explanation of some aspect of
the nature of science and does not assume students will discover this knowledge on their
own (p.32). This was further supported by Reeves et.al (2007), better results may be
obtained when labs are a combination of student inquiry and clear, explicit instruction by
the teacher (p.32).
My focusing question during the first part of the lab exercise was an inquiry
question that iwas nonthreatening for as Colburn (2004) suggested any honest response is
an acceptable answer and provides the teacher with information to determine what
students do and do not understand (p.33). Another element of the nature of science that
the students touched on in the lab experiment was that of subjectivity. The students had to
observe if there was a colour change in the water and in the dialysis tube. McComas
(2004) notes that science has a subjective element where analysis is ultimately personal
and subjective (p.26). McComas (2004) suggests that ideas and conclusions must be
reviewed by other experts in meetings and through the publication of a peer review
system (p.26). The students worked as a collaborative team. Having the students discover
and discuss their results together allowed the students to see that their visual observations
may not be the same as others. This exercise acted as a peer collaboration and review.
Colburn (2004) mentions that differing data among students is not wrong, but students
should be able to explain why they think the results came out the way they did (p.35).
Several times during the lesson, I allowed for review. Reeves et al (2007) notes that
when students do not retain an understanding of the nature of science the first time it is
presented, we suggest that teachers reinforce the basic characteristics of the nature of
science, frequently and persistently with mini-lessons (p.35).
The last nature of science point in my lesson is that science and technology impact
each other, but they are not the same (McComas 2004, P.26). The real life technology
examples (reverse osmosis for water purification) that I mention at the end of the lesson
were to demonstrate that technology can be the result of pure science.
If I were to change this lesson I would have the osmosis lesson and the first of the
lab on one day. On the second day I would have a review of passive transport followed
by observation and results of the lab. The extra time would allow for a better absorption
and understanding of what is happening with the lab by the students. The extra day would
also garner greater changes in the dialysis tubing.
References:
Colburn, Alan. (2004). Focusing Labs on the Nature of Science. Science Teacher 71(9),
32-35.
Fisher, K. (1997, January 14). Basic Processes
(Solution, Evaporation, Diffusion and
Osmosis). Retrieved from
http://www.biologylessons.sdsu.edu/classes/lab5/altern.html
Gue, D. et al. (2004). Science Focus 10. Toronto, Canada: McGraw-Hill Ryerson.
McComas, W.F. (2004). Keys to Teaching the Nature of Science. Science Teacher 71(9),
24-27.
Program of Study. (2005). “Science Grade 10”. Alberta Learning. Edmonton, AB.
Reeves, C, Chessin, D, & Chambless, M. (2007). Nurturing the Nature of Science. The
Science Teacher, 74(8), 31-35.