Unit 6: Investigative project
C: Safely undertake the project, collecting, analysing and presenting the
results
D: Review the investigative project using correct scientific principles
Project implementation and review
By: Ryan Osman
Abstract: Caffeine is used in everyday life for many to achieve the
feeling of alertness. The hearts of Daphnia magna are said to be
equivalent to human hearts. The Daphnia are used to check if different
compounds have the same impact on their heartbeat as they would in
a human heart. The expectation was that giving the Daphnia caffeine
would increase them to have more heart beats per minute. The goal of
this experiment was to look into the effects of caffeine on the heart,
and the Daphnia Magna was chosen as the test subject. The theory was
that increasing the amount of caffeine in the Daphnia Magna's
environment would cause its heart rate to rise. To test this
hypothesis daphnia was exposed to caffeine and its heart rate
recorded by placing it on a microscope slide and counting the
number of heart beats. As a result, the heart beat increased, this
is due to the fact that it is a stimulant that alters adrenaline levels.
Introduction: daphnia is known as a small semi-transparent freshwater
crustacean with a conspicuous solitary eye and lengthy antennae. They
are often called water fleas because they swim in a jerky motion, also
they are small in size approximately about 0.5mm to 1cm. The heart of
Daphnia magna is said to be equivalent to human hearts. The Daphnia
are used to check if different compounds have the same impact on
their heartbeat as they would in a human heart. When caffeine is
added the expected results is that daphnia heart rate will increase.
Caffeine is known to raise the heart rate of daphnia. This is due to the
fact that it is a stimulant that alters adrenaline levels. A rise in heart
rate results from the combination of these factors. In normal
conditions, an increase in caffeine intake will raise heart rate.
Hypothesis: the purpose of the investigation is to see how caffeine
affects the heart rate of daphnia. As a results caffeine increases the
heart rate of daphnia.
, Method:
Use a cavity slide to place a few strands of cotton wool.
Use a pipette to get one daphnia out of the pond water.
Drop the daphnia into the cavity slide.
Take the same cavity slide and place it under a light microscope.
Make sure the microscope is turned on, put the daphnia near the
centre using the clips on the microscope and start with lowest
power length.
Focus on the heart of the daphnia using the microscope eye.
Use a pencil technique, take a pencil and piece of paper draw
dots on the paper for about 20 seconds to count the heart rate
before the solution have been added.
Times the 20 seconds by 3 to find out the beats per minute.
Remove the pond water with a tissue and replace it with about 2
drops with different concentration of caffeine solution such as
0.2M, 0.3M, 0.4M or 0.5M around the daphnia.
Leave it for a minute so you can measure the heart rate after the
solution have been added.
Carry out the same procedure for 5 different caffeine
concentration such as 0.2M, 0.3M, 0.4M, and 0.5M. make sure to
repeat it at least 3 times for more accurate results.
Results:
Caffeine concentration (%) Mean (Bpm) Standard Standard
error error
positive negative
0.00 317.6 327 308
0.02 325 329 321
0.03 343 346 340
0.05 353.3 358 349
C: Safely undertake the project, collecting, analysing and presenting the
results
D: Review the investigative project using correct scientific principles
Project implementation and review
By: Ryan Osman
Abstract: Caffeine is used in everyday life for many to achieve the
feeling of alertness. The hearts of Daphnia magna are said to be
equivalent to human hearts. The Daphnia are used to check if different
compounds have the same impact on their heartbeat as they would in
a human heart. The expectation was that giving the Daphnia caffeine
would increase them to have more heart beats per minute. The goal of
this experiment was to look into the effects of caffeine on the heart,
and the Daphnia Magna was chosen as the test subject. The theory was
that increasing the amount of caffeine in the Daphnia Magna's
environment would cause its heart rate to rise. To test this
hypothesis daphnia was exposed to caffeine and its heart rate
recorded by placing it on a microscope slide and counting the
number of heart beats. As a result, the heart beat increased, this
is due to the fact that it is a stimulant that alters adrenaline levels.
Introduction: daphnia is known as a small semi-transparent freshwater
crustacean with a conspicuous solitary eye and lengthy antennae. They
are often called water fleas because they swim in a jerky motion, also
they are small in size approximately about 0.5mm to 1cm. The heart of
Daphnia magna is said to be equivalent to human hearts. The Daphnia
are used to check if different compounds have the same impact on
their heartbeat as they would in a human heart. When caffeine is
added the expected results is that daphnia heart rate will increase.
Caffeine is known to raise the heart rate of daphnia. This is due to the
fact that it is a stimulant that alters adrenaline levels. A rise in heart
rate results from the combination of these factors. In normal
conditions, an increase in caffeine intake will raise heart rate.
Hypothesis: the purpose of the investigation is to see how caffeine
affects the heart rate of daphnia. As a results caffeine increases the
heart rate of daphnia.
, Method:
Use a cavity slide to place a few strands of cotton wool.
Use a pipette to get one daphnia out of the pond water.
Drop the daphnia into the cavity slide.
Take the same cavity slide and place it under a light microscope.
Make sure the microscope is turned on, put the daphnia near the
centre using the clips on the microscope and start with lowest
power length.
Focus on the heart of the daphnia using the microscope eye.
Use a pencil technique, take a pencil and piece of paper draw
dots on the paper for about 20 seconds to count the heart rate
before the solution have been added.
Times the 20 seconds by 3 to find out the beats per minute.
Remove the pond water with a tissue and replace it with about 2
drops with different concentration of caffeine solution such as
0.2M, 0.3M, 0.4M or 0.5M around the daphnia.
Leave it for a minute so you can measure the heart rate after the
solution have been added.
Carry out the same procedure for 5 different caffeine
concentration such as 0.2M, 0.3M, 0.4M, and 0.5M. make sure to
repeat it at least 3 times for more accurate results.
Results:
Caffeine concentration (%) Mean (Bpm) Standard Standard
error error
positive negative
0.00 317.6 327 308
0.02 325 329 321
0.03 343 346 340
0.05 353.3 358 349
