Daphnia Experiment Report
Daphnia Experiment Report
1. Introduction
Caffeine is found in many plant species, where it acts as a natural pesticide. It is found most commonly in cocoa, tea and coffee, but is also artificially added to some soft drinks such as cola to act as a flavour enhancer. When consumed by humans, caffeine works as a stimulant causing amounts of released neurotransmitters to be increased. High use of caffeine has been related with raised blood pressure, restlessness, insomnia and anxiety which, in the long term, can lead to heart and circulation problems.
The aim of this experiment is to observe whether caffeine has any significant effect on heart rate. To test this, daphnia will be placed in water and then caffeine solution, so the difference in heart rates can be compared.
Daphnia are small invertebrates that are found in aquatic environments, more commonly known as ‘water fleas’. They are approximately 3mm in length and have simple internal structures. They have transparent skin that allows you to view their internal organs, making them ideal subjects for scientific experiments.
2. Hypothesis
It is expected that the daphnia’s heart rate will be greater in the caffeine solution than in the water. This prediction can be justified with the fact that caffeine is a stimulant drug that affects the central nervous system, speeding up your metabolism and increasing alertness.
3. Method
The independent variable in this experiment is the use of caffeine.
The dependent variable in this experiment is the heart rate of the daphnia.
Equipment:
* Pipette | * Cotton wool | * Concaved microscope slide | * Water (20cm²) | * Microscope slide cover | * Caffeine Solution (20cm²) | * Microscope | * 1 daphnia | * Thermometer | * Stopwatch/timer | * Petri dish * Two experimenters | * Pen * Paper |
1. A concaved microscope slide is placed in a lidless Petri dish. 2. A tiny strand of cotton wool
1. Introduction
Caffeine is found in many plant species, where it acts as a natural pesticide. It is found most commonly in cocoa, tea and coffee, but is also artificially added to some soft drinks such as cola to act as a flavour enhancer. When consumed by humans, caffeine works as a stimulant causing amounts of released neurotransmitters to be increased. High use of caffeine has been related with raised blood pressure, restlessness, insomnia and anxiety which, in the long term, can lead to heart and circulation problems.
The aim of this experiment is to observe whether caffeine has any significant effect on heart rate. To test this, daphnia will be placed in water and then caffeine solution, so the difference in heart rates can be compared.
Daphnia are small invertebrates that are found in aquatic environments, more commonly known as ‘water fleas’. They are approximately 3mm in length and have simple internal structures. They have transparent skin that allows you to view their internal organs, making them ideal subjects for scientific experiments.
2. Hypothesis
It is expected that the daphnia’s heart rate will be greater in the caffeine solution than in the water. This prediction can be justified with the fact that caffeine is a stimulant drug that affects the central nervous system, speeding up your metabolism and increasing alertness.
3. Method
The independent variable in this experiment is the use of caffeine.
The dependent variable in this experiment is the heart rate of the daphnia.
Equipment:
* Pipette | * Cotton wool | * Concaved microscope slide | * Water (20cm²) | * Microscope slide cover | * Caffeine Solution (20cm²) | * Microscope | * 1 daphnia | * Thermometer | * Stopwatch/timer | * Petri dish * Two experimenters | * Pen * Paper |
1. A concaved microscope slide is placed in a lidless Petri dish. 2. A tiny strand of cotton wool