Lesson plan
Length:80 mins
​
​
​Subject: Plant responses
Topic: regulation of growth, external growth factors,
tropisms.
Previous knowledge and experience: Pupils should have a
large amount of previous knowledge on the topic. They
should know about the factors that affect plant growth from
their everyday lives such as seeing plants in their
surroundings daily. Students should know how light,
temperature and water effect plant growth. From The Junior
Certificate cycle I expect pupils to have a good understanding
of what a Tropism is and be able to explain a plants response
to light and gravity from theOB50 investigation on the growth
response of plants to light (phototropism) and gravity
(geotropism) (NCCA 2006). I do not expect all students to
have a good understanding of thigmotropism, hydrotropism or
chemotropism but I expect them to be able to work out using a
break-down technique of the words e.g. hydra-water, chemochemical. I expect some students to hold the misconception
that plants are passive and defenceless and that plants don’t
respond to stimulus like humans do. A true understanding of
what a Tropism is should clear up misconceptions within the
different examples.
Aims:
• To overcome pupils misconceptions in relation to plant
responses and tropisms.
Objectives:
• Pupils should be able to come to terms with their current
misconceptions and realise their errors.
• Pupils should be able to overcome their misconceptions
and form accurate scientific understanding of the topics
being addressed.
• Pupils should gain an interest in plants and become
aware of how multifaceted they are.
• Pupils should improve their communication skills
through group work.
• Pupils should improve their critical thinking through
investigation.
Subject matter:
Pupils will learn that plants are able to respond even though
they lack a nervous system and instead depend on a chemical
coordination for their responses. Pupils will learn that plant
responses involve plant growth and growth changes. Growth
regulation in plants is affected by internal and external factors
such as light, day lengths, gravity, temperature and chemicals.
Pupils will learn that a tropism is a change in the direction of
growth in a plant in response to a change in the external/
environmental stimulus. Pupils will evaluate what
phototropism and geotropism is through investigation and
pupils will learn what thigmotropism, hydrotropism and
chemotropism are.
Resources:
Mini-white boards, YouTube video, concept cartoon,
questions and answer activity cards (end of lesson),
PowerPoint presentation and slide show- investigation Dandelion
stem, 3ml plastic pipette, scissors, Blu-tak, Graph paper, shoes box.
https://www.youtube.com/watch?v=uX5eoxKbzHE
http://spacegarden.net/downloads/Gravitropism.pdf
Time
Pupil Activity
Teacher activity
Reference
Goal conception for set induction:
Common
• There are many factors that affect misconception in
plant growth ,light is just one of relation to set
them and plants can grow, to some induction:
• plants need
degree, in darkness
• Gravity is not essential to the normal
only light
characteristics of root growth, plants
to grow
could use light to direct root growth.
•
roots only
grow down
because of
gravity.
Set Induction:
Pupils will each receive a mini-white
7mins board. Pupils will answer and come up
with ideas to answer the questions in the
concept cartoon and the teacher’s
questions.
1. True or false: Both plant and
animals response to environmental
stimuli is equally complex.
2. What are the factors that affect
plant growth?
3. What is a tropism?
4. Whats the difference between a
positive and negative tropism?
5. What stimulus causes
(photo,hydro,chemo,thigmo,geo)tr
opism? And how does the plant
respond to it generally?
6. Which they think is more important to
‘Concept cartoons
can reveal the
Hand each pupil students’
out a mini
misconceptions, make
whiteboard. Ask high
students to answer participation class
question and share discussions possible
ideas about the
on the causes of
concept cartoon. them, make students
enthusiastic about
learning,
consequently can
eliminate existent
misconceptions.
(World Conference
on Educational
Sciences 2009).
Mini whiteboards
allow monitoring of
a plant, phototropism or geotropism.
all pupils rather than
just questioning a
few.
7 mins
Pupils will be asked to take note of what The teacher will
they observe in the first half of the video. inform the students
Questions to ask:
they will be
1. How do you think a seed will grow
watching a short
differently in space, compared to the
video which
same plant on Earth?
compares seeds
2. What will happen to the stem?
grow on earth
3. What will happen to the roots?
4. Will there be any other differences? (with gravity)and
5. If they were carrying out a plant
growth experiment on Earth and in
space, which factors would they
control?
The pupils will watch the second half of the
video and compare/contrast any
similarities/differences they see.
seeds grow in the
international space
station on the
moon(without
gravity)
The video shows
that still grow
upwards and the
roots largely grow
downwards,
although the slant to
the left is somewhat
increased. The
scientists concluded
that gravity was not
essential to the
normal
characteristics of
root growth, and that
in its absence, the
plants could use
light to direct root
growth.
Phototropism has a stronger impact on
shoots than the geotropism pull down.
Hydrotropism and chemotropism affect
root growth and they can grow laterally if
conditions are too acidic( chemo) or if the
water source is in that direction(hydro) .
Development:
Misconception:
Shoots always
grow up and roots
always grow
down.
Without light shoots can still grow up and
without gravity roots can still grow down.
20
mins
The teacher will The process of
put the students
investigation helps
into groups of 2/3 students to
to set up and carry Understand how
out an experiment scientific ideas are
on geotropism.
developed. It
The teacher will provides students
explain the
with opportunities to
The students will work in groups to set up experiment set up use and
the experiment. Once completed they will and go through
apply their
make predictions as to what they think
safety precautions knowledge and
will happen. The set ups will be left until with the class.
understanding while
later in the lesson to view the results.
A slide will be put solving a problem.
Questions:
up on the board via (NCCA)
What do you expect to happen?
projector
Why? How? How does your hypothesis throughout the
relate to geotropism?
experiment for
student to look at
Experiment set up :
as a reference.
See below.
Each student in the group will take turns
monitoring the experiment every 10 mins.
20 mins The students will get an A1 sized sheet so
they can draw the set up for each procedure
and any extra points they need to make.
Using their knowledge about tropisms and
phototropism they will evaluate 3 different
scenarios relating to a plants response to
phototropism.
10 mins Each group will present their ideas and the
class will come to a consensus about their
predictions and results.
After the geotropism
experiment the
teacher will give the
students pictures of
apparatus via
Powerpoint. The
students will work in
group to come up
with an experiment
using the apparatus
listed to test their
theories about
phototropism.
The teacher will
leave the
Powerpoint on the
board for the
duration of the task.
use scientific
knowledge to turn
ideas into a
form that can be
investigated and to
plan
accordingly.
(NCCA)
students engaged in
inquiry based activities
to aid in
deconstruction of their
misconceptions.
The teacher will
circulate the room
and monitor
students’ progress.
The teacher will
show a time lapse
video of results.
Information and
communication
technologies
(ICTs) can enhance
the teaching and
learning of
science. Teachers
may use ICT to
complement
classroom or
laboratory activities,
to prepare and
present
classroom learning
materials.(NCCA)
Students will get the final results from the
dandelion experiment that was set up earlier.
The students will see that the stem reverts
10 mins back to a vertical position.
Questions:
Why has they happened?
How has it happened?
Thinking back to the video about the plants
https://www.youtube.co
grown on the moon, what would you expect to
m/watch?
happen if the orientation of the stem was
v=EM77i5vEJig
continuously changed e.g. a petri dish with
cress seedlings was set up vertically and it
Go through pupils
was rotated continuously?
answer to questions
What way would you expect the plants to
at the end of activity.
grow? Why?
What would you us as a control?
As it is nearing the end
of the lesson this will
keep the students
engaged and introduce
a new tropism.
The teacher will
show a short clip
(David Attenborough
Venus fly trap) which
relates to
thigmotropism.
Conclusion:
Teacher will hand
Recapping on
5 mins One pupil will begin by calling out their
out question answer material covered in
cards- one to each the classroom aims to
question. The rest of the class will have to
pupil.
confirm pupils
check their cards searching for the correct
learning in the lesson
answer. The pupil who has the correct answer
‘revisit common
will then call out their answerto the class.
misconceptions as
They will then call out their question and the
often as you can.
same procedure will follow until everyone has
Assess and reassess
asked a answered a question.
the validity of student
concepts.’ (National
(e.g. act out / mime/ draw on the board/ sign
research council 1997).
phototropism-stand by the window and begin
to lean towards the light)
A
Evaluate: during this
charades/Pictionary stage the instructor can
style game will be
assess their students
played where
ability to use the
students must act
concepts correctly.
out a certain plant
response and the
other students must
guess through the
actions.
Experiment set up:
Dandelion stems (Taraxicum officianale) have a strong geotropic response. If the stems are detached
from the plant and held sideways for a period of time, they will reorient themselves by bending
upwards until they return to a near vertical position. The response is much quicker if the
inflorescence is removed.
Safety Notes
Care should be taken if using razors to cut the pipettes to size and to remove the dandelion
flowers. Sharp scissors can be used as an alternative.
apparatus
Per group
••
Dandelion stem
••
3ml plastic pipette
••
scissors
••
Blu-tak
••
Graph paper
••
Shoe Box to cover the dandelion
The dandelion scapes should be at least 15cm long, without bruises, and as straight as
possible. Handle them as little as possible, and keep them in water until they are needed. It is
important to keep the scapes upright to avoid stimulating the geotropic response before the
practical begins.These experiments are best carried out with stems carrying a bud, rather than
an open flower or a ‘dandelion clock’.
In order to avoid confusion with phototropism, the dandelion stem will be in darkness.. Graph paper
can then be stuck to the back of the box file to enable students to measure the rate at which the
dandelion is curving upwards.
Instructions
1. Take a plastic pipette, and snip off the end at a point where it is just wide enough to
insert the base of your dandelion stem.
2. Fill the pipette with water by holding it under a tap.
3. Push the base of the stem into the pipette.
4. Gently push blu-tak around the stem and the pipette to prevent water leaking out.
5. Cut the bud off the top of the stem.
6. Stick the pipette down on the bench with blu-tak. Make sure that the stem is
horizontal.Record the time.
7. Position a piece of graph paper behind the stem, to make it easier to see the
movement.
8. Observe the stem at intervals, and record its height against the graph paper.