Floating Leaf Disks Lab (Photosynthesis)
Summary
TLDRIn this instructional video, Mr. Buss guides viewers through setting up a floating leaf disks lab to demonstrate photosynthesis. One person prepares leaf disks by punching holes between leaf veins. Another mixes a sodium bicarbonate solution with detergent to create carbon dioxide. Disks are loaded into syringes, submerged in the solution, and tested under light and dark conditions. The experiment observes how many disks float due to oxygen release, illustrating photosynthesis in action.
Takeaways
- 🌿 Prepare spinach leaves by punching holes between the veins to create leaf disks.
- 👥 Assign tasks in a group: one person prepares leaf disks, the other prepares the bicarbonate water solution.
- 💧 Use a 600 ml beaker and fill it with 300 ml of water for the bicarbonate solution.
- 🧂 Add three grams of baking soda (sodium bicarbonate) to the water to provide carbon dioxide for photosynthesis.
- 💧 Add a drop of detergent to the solution to prevent leaf disks from sticking to the water surface.
- 🔬 Photosynthesis combines carbon dioxide, water, and light energy to produce glucose and release oxygen.
- 💉 Use a syringe to load leaf disks and bicarbonate water, ensuring no air bubbles are trapped.
- 🌱 Place leaf disks in small plastic cups submerged in the bicarbonate water, ensuring they start at the bottom.
- 💡 Set up an experiment with light and dark conditions to observe the effect on leaf disks.
- ⏱️ Record the number of leaf disks that float every minute for 15 minutes.
- 🌞 Leaf disks in the light condition will start to float due to the release of oxygen from photosynthesis.
Q & A
What is the main purpose of the floating leaf disks lab?
-The main purpose of the floating leaf disks lab is to demonstrate the process of photosynthesis, particularly the release of oxygen gas which causes the leaf disks to float.
Who is Mr. Buss in the context of the script?
-Mr. Buss is the instructor guiding the group through the setup and execution of the floating leaf disks lab.
What is the role of one person in the group during the lab setup?
-One person in the group is responsible for obtaining spinach leaves and creating leaf disks by punching holes between the veins of the leaves.
How many leaf disks should each group have initially?
-Each group should aim to have four piles of about ten leaf disks each.
What is the purpose of using baking soda in the lab?
-Baking soda, or sodium bicarbonate, is used as a source of carbon dioxide, which is essential for the photosynthesis process.
Why is detergent added to the bicarbonate water solution?
-Detergent is added to prevent the leaf disks from sticking to the surface of the water and to allow them to sink.
How much bicarbonate water solution is prepared in the lab?
-A 300 ml solution of bicarbonate water is prepared in a 400 or 600 ml beaker.
What is the role of the syringe in the lab procedure?
-The syringe is used to load leaf disks and bicarbonate water solution, ensuring that air bubbles are removed before the disks are placed in the experimental cups.
How many leaf disks are placed in each cup for the experiment?
-Twenty leaf disks are placed in each cup for the experiment.
What are the two different conditions under which the leaf disks are tested?
-The leaf disks are tested under light and dark conditions to observe the effect of photosynthesis.
How often should the number of floating leaf disks be recorded during the experiment?
-The number of floating leaf disks should be recorded every minute for a duration of 15 minutes.
What causes the leaf disks to start floating during the experiment?
-The leaf disks start to float due to the release of oxygen gas during photosynthesis, which forms bubbles on the disks.
Outlines
🌿 Setting Up the Floating Leaf Disks Lab
Mr. Buss introduces the floating leaf disks lab, detailing the setup process. One person should prepare spinach leaves by punching out disks between the veins to avoid damaging them. The goal is to create four groups of ten leaf disks. Another person should prepare a 300 ml solution of 3 grams of sodium bicarbonate (baking soda) in water, which serves as a carbon dioxide source for photosynthesis. A drop of detergent is added to prevent leaf disks from sticking to the water surface. The leaf disks are then loaded into a syringe, filled with the bicarbonate solution, and checked to ensure they sink. The process of removing air from the syringe and ensuring all disks are submerged is explained. Finally, the disks are placed into plastic cups for the experiment.
🔬 Observing Photosynthesis in Leaf Disks
The experiment involves placing leaf disks under light and dark conditions to observe photosynthesis. The setup includes 20 leaf disks in each condition, ensuring they are submerged and not floating. Over a 15-minute period, the number of disks that float to the surface is recorded every minute. Floating is an indication of photosynthesis occurring, as oxygen bubbles form on the disks, causing them to rise. The observation concludes that all disks in the light condition float, while none in the dark condition do, demonstrating the necessity of light for photosynthesis.
Mindmap
Keywords
💡Floating Leaf Disks
💡Photosynthesis
💡Bicarbonate Water Solution
💡Carbon Dioxide
💡Detergent
💡Light Condition
💡Dark Condition
💡Glucose
💡Oxygen
💡Sodium Bicarbonate
💡Control Experiment
Highlights
Introduction to setting up and running the floating leaf disks lab.
One person should prepare spinach leaves and create leaf disks.
Leaf disks should be punched out between the veins.
Leaf disks are sorted into groups of ten.
Another person should prepare the bicarbonate water solution.
A 600 ml beaker is used to prepare 300 ml of solution.
Add three grams of baking soda to the solution.
One drop of detergent is added to prevent leaf disks from sticking to the surface.
Baking soda dissolves to provide carbon dioxide for photosynthesis.
Photosynthesis combines carbon dioxide, water, and light energy to produce glucose and oxygen.
Leaf disks are loaded into a syringe and submerged in bicarbonate water.
Air bubbles are removed from the syringe to ensure leaf disks sink.
Leaf disks are placed in small plastic cups for the experiment.
Leaf disks should be at the bottom and not floating at the start.
Leaf disks are divided between light and dark conditions.
Leaf disks in the light start to float due to oxygen release from photosynthesis.
Oxygen bubbles form on the leaf disks, causing them to float.
After 15 minutes, all leaf disks in the light are floating.
No leaf disks float in the dark condition, indicating the necessity of light for photosynthesis.
Transcripts
hello this is mr. buss and I'm gonna
walk you through how to set up and run
the floating leaf disks lab and so one
person in the group to get started
efficiently if you have a group of two
it's helpful if one person takes care of
getting a few spinach leaves and getting
some of the leaf disks created and so
what you're gonna want to do is take the
whole bunch and then try to punch out
spaces between the veins of the leaf try
not to punch holes from the veins
so I quenched a bunch of holes out of
the leaves and these little leaf disks
and I'm going to try to sort these into
groups of ten
okay so here I have four groups of ten
and I just kind of took some of the ones
that weren't very well punched or
whatever has some extras off to the side
in case I need them later so one person
in the group try to get four piles of
about ten or so the other person in the
group prepared the bicarbonate water
solution so take a larger beaker this is
a 600 ml beaker you know 400 or 600
works and then fill it up to a total of
300 mils 300 and then then I'm going to
add three grams of baking soda so sodium
bicarbonate and then mix that up and
then it can be helpful to add one drop
of detergent that's plenty
okay so the baking soda is going to be a
source of carbon dioxide actually the
baking soda the sodium bicarbonate is
going to dissolve in there and so that
you know obviously in photosynthesis the
plant cells need start with carbon
dioxide combines water and light energy
to yield energy molecule like glucose
and releases oxygen the detergent just
allows these to sink sometimes they want
to stick to the surface of the water and
the detergent is going to prevent that
from happening so once this is all set
you've got your bicarbonate water you've
got your piles of leaf disks take a
syringe remove the plunger and load a
pile of ten disks into the plunger into
the syringe I mean okay
put the plunger back in don't crush them
just push it down most of the way pull
up some of your bicarbonate water now
I'm going to get all the air out I
filled it up about halfway I'm gonna put
my thumb on the end and I'm gonna pull
back on the plunger shake that's gonna
remove the air from inside and I'm gonna
push up and you can see some of the leaf
disks are floating and some are sunk so
I'm gonna repeat that process cap it
with the thumb pull back on the plunger
shake and push up on the plunger and
they are all sunk
so here I have ten leaf disks put them
in one of the small plastic cups so I'm
going to add ten more to my plunger or
to my syringe put the plunger back on
pull up some more bicarbonate water
okay so I have about 20 leaf disks in
each I'm going to double check that
they're all sunk to the bottom I can
count up exactly how many I have in each
if I don't have exactly 20 I'm gonna top
each of the containers off a little bit
with the rest of my carbon dioxide water
so here's my setup I should have equal
numbers of leaf disks in each should be
20 they should be something in the
bottom and not not floating at the top
to start so you should all be at the
bottom if any are floating to start the
experiment remove them and then I'm
going to put one of these under a light
condition and one of them under a dark
condition so here I have 20 of the leaf
disks sunk down in the light condition
and then I just put the other 20 in a
lab drawer that'll be the dark
environment and so over the next 15
minutes I'm going to record how many
float every minute I'm going to check
and see how many have started to float
so you can see that over time I'm a
couple minutes into this here's the
first leaf Chad that's starting to float
to the surface and again at each bin and
I'm gonna just check and see how many of
them are actually floating and here
comes the second one so remember you're
checking the ones that are in the light
also the ones that are in the dark so
you might ask yourself why do they start
to float and remember that
photosynthesis is going to be releasing
oxygen and so you can kind of see
oxygen bubbles starting to form on the
leaf disks and so that's why they're
floating because they're releasing
oxygen gas and that's causing them to
float so after 15 minutes looks like all
of the leaf disks in the light we're
floating there aren't any on the bottom
anymore it might look like there are but
there aren't it's just a weird
reflection and then in the dark I didn't
have any of them
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