Dawid Biczysko
18019730
Level 3 Science
Cabombs Pondweed
Introduction: In this assignment I will go through my pond weed
photosynthesis test. I will explain in stages, my aim, hypothesis,
variables, the apparatus, safety hazards, methods, the results and
observations.
Aim: Our aim for this experiment is to find out how the distance of light
affects photosynthesis when it comes to plants for this test we will be
using pondweed. We want to find out if the number of bubbles with
oxygen will increase or decrease as the light is further away from the
plant. This will give us the answer that we need in order to finish our
experiment.
Apparatus: A lamp, pondweed, clicker, Iodine vapour tank, test tube,
paper clip and a clamp
Safety Hazards: When it comes to this experiment we must be careful
with the equipment as the lamp can be very dangerous. The light is very
strong and could permanently or periodically blind us. This means that
we should be careful to not look directly at the light as it could burn our
eyes and damage our vision. We must also be careful to not break any
glass when handling the test tube or the Iodine vapour tank. Broken
glass could mean that we could cut our skin, or get pieces of glass
shards in our hands, feet or even our face.
Hypothesis: My hypothesis / prediction is that the number of bubbles
will be higher the closer the light is to the pond weed / test tube. The
further the test tube is from the light, the less bubbles will be produced,
this is because I believe the rate of photosynthesis will decrease as the
light intensity decreases.
Variables
Independent Variable – The distance
Dependent Variable – Number of bubbles
Control Variables – Source of light, pondweed, same area / room
How will we make the investigation reliable?
, Dawid Biczysko
18019730
Level 3 Science
We will aim to make the investigation reliable by using the same light
source, same distances, the same room as well as, repeat the process
three times for efficiency purposes.
Method:
1. Pick a pondweed from the container and cut the stem so it does
not stick out of the test tube, then attach a paperclip to the
pondweed so that it sinks and stays in place under the water.
2. Next place the pondweed in the test tube and clamp it in front of
the light source.
3. Fill up the Iodine vapour tank with water and place the it in front of
the pond weed so that it is closer to the light than the test tube, this
will protect the test tube from heating up.
4. Turn on the light and count the number off bubbles that the
pondweed gives off in 1 minute.
5. Finally start off at 10cm going up in 10cm every time you need a
new result, stop at 50cm and repeat the process.
