Painkillers: demerol morphine Error caffeine could have been more concentrated heartbeat counting might not have been 100% accurate some coating left on caffeine What did we use? See the Science Buddies project. At this time of economic fragility in the field, sudden and frequent leadership changes--especially ones that are not for mutual reasons--are of concern to all of us, since they affect the stability of the field. Dependent variables: Number of heart beat per 20s Other variables: 1. Once you have determined the correct concentration range to test, you will test many individuals at each concentration, and space your test concentrations more closely e. An additional, larger dish outside the small one could also be filled with water at the appropriate temperature to help reduce heat loss from the experimental chamber. Daphnia possess a less developed nervous system compared to humans, so they have a reduced awareness of pain. Again, four cups were used for the control, using spring water.
Its effects range from mild alertness to heightened anxiety and body tension. Five daphnia were then placed in each container for ten minutes. Safety Any student known to suffer from photosensitive epilepsy should be warned before a stroboscopic light is used. As a result the effect other factors other than coffee content are limited. This experiment was done two times, and a paired t test analysis vs control indicate the following P values: 0. Caffeine increases the heart rate of Daphnia. In other words, at the lowest concentration you see no resonse, and at the highest concentrations you see a maximal response, with several intermediate responses in between.
Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants, as well as enhancing the reward memory of pollinators. Same culture of Daphnia: To minimise genetic differences. Caffeine increases the heart rate of Daphnia. However, designing such an experiment involving human subjects that would be both safe and scientifically valid is way beyond the level of a science fair project. Noradrenaline and adrenaline: In contrast, heart rate is increased by the sympathetic nervous system neurotransmitter: noradrenaline and the hormone adrenaline circulating in the blood via activation of cell surface receptors in the sinoatrial node - pacemaker called beta-1 adrenoceptors. Aim: In this experiment we are trying to find out how varying the concentration of caffeine can affect the heart rate of Daphnia shrimp. You will obviously want your highest concentration to be less than this, because you are interested in effects on heart rate see the section for a science project using Daphnia to monitor toxicity of compounds in water.
It will be easy to discover and count the heart rate of Daphnia as long as the Microscope is set up correctly. After the daphnia were exposed to the concentrations for ten minutes, we used micropipettes to remove them from the solution and place them under a compound microscope. I need to try and limit the human error in the experiment as the daphnia heartbeat is very quick so it will be hard to be completely accurate so we are using the blind method. Set its reading to zero and add 1 to the answer. Brush Creek's levels of nitrate, chlorine and phosphate were comparable to the levels in the other creeks, but the concentration of nitrate and the pH level at Brush Creek were the highest of the sites tested.
These will be for holding your experimental and control groups before testing. Daphnia has two pairs of antennae which are used for swimming. The age controls were set by placing individual adult Daphnia magna in plastic cups filled with spring water. How were drug solutions prepared? To achieve this, the type and extent of the effect in humans at the same drug concentration the human template must be known. Before you conduct your experiment, it is a good idea to do a pilot experiment first in order to determine the right range of concentrations of caffeine to test. Hypothesis: I believe that the amount of caffeine in the blood will be directly proportional to the Daphnia's heart rate. I think they should clarify the followings points: 1.
Most importantly, they have a chambered heart, which can be seen beating under a microscope. After examining the books of information, I decided to talk with some people living in the area about their water supplies. Background: Caffeine is a white crystalline, a bitter alkaloid C8-H10-N4-O2 usually derived from coffee or tea and used in medicine chiefly as a nervous system stimulant. Then you replay the video in slow motion and count the heart beats again. These experiments were part of a study, where 18 different molecules were tested for their effect on heart rate, however, only caffeine, dopamine and ethanol showed drastic changes. In order to stick to the alibi, more and more lies form, and eventually the lawyer finds things that do not match add up.
Leave the Daphnia immersed in the 0. The smaller pair of antennae serves as a sensory function and the larger one is used for swimming. During both of my experiments, my raw data was documented in a notebook and then transferred to a computer for analysis at the end of the experiments. It is the world's most widely consumed psychoactive drug, but unlike many other. The control for this experiment is a solution with no caffeine which allows us to see if the change in heart rate is due to the caffeine or other factors.
Teaching notes Daphnia is poikilothermic, which means that its body temperature and therefore its metabolic rate are affected directly by the temperature of the environment. It helps to increase heart rate. Each heartbeat is recorded by tapping a pencil on a piece of paper and counting up the pencil marks after the specified time. Sorry, but copying text is forbidden on this website! An individual Daphnia is placed in the depression and then coverslipped for viewing. As expected, the daphnia that were exposed to the 1% concentration of caffeine had a significant increase in heart rate.