Experiment. Hypotheses: The higher the concentration of caffeine the higher the heart rate of the daphnia.
The effect of caffeine concentration on daphnia's heart rate Hypotheses: The higher the concentration of caffeine the higher the heart rate of the daphnia. Biological information: caffeine speeds heart rate, and circulation. Caffeine is a stimulant drug, which causes increased amounts of stimulatory neurotransmitters to be released. It belongs to a Group of chemicals called methylxanthines. Caffeine and similar compounds also inhibit a class of enzymes known as cyclic nucleotide Phosphodiesterases. These enzymes are, in part responsible for degrading a stimulatory signal produced when excitatory neurotransmitters activate different neurons in the central nervous system (CNS). When they are inhibited by caffeine, the stimulatory signal remains active for a longer period of time resulting in a greater sense of alertness (a CNS effect). Independent variable: concentration of caffeine 0- 0.5% Dependant variable: this is the heart rate (BPM) Controls: 0% caffeine to check that water alone does not have an effect on the heart rate compared to pond water. Other fixed/controlled variables: The temperature must always stay constant this means that it must be fixed at room temperature. This can be done by removing the light source from the microscope when not counting because it increases the temperature which leads to an increase in metabolism and therefore an increase in the
Mole Ratios in a Chemical Reaction
Renee Buettel Period D4 Ms. Parziale /7/08 Lab #10: Mole Ratios in a Chemical Reaction Paul Bergin Abstract The main objective of this lab experiment was to balance the given chemical equation and to find the correct mole-to-mole ratio of it. The theoretical balanced equation was Pb(NO3)2(aq) + K2Cr2O7(aq) --> PbCr2O7(s) + 2KNO3(aq). In addition, the ratio of moles was one to one.and the correct mole-to-mole ration was one to one. The experimental results matched this ratio. The theory that was proven was that balancing equations give the correct mole ratio of a chemical equation. Introduction In a chemical equation, there are two sides. The chemicals on the tail end are called the reactants and the chemicals on the other side are called products. An example of this given by Coefficients (2008) is 2H2 + O2 --> 2H2O. In this example, "2H2 + 02" is the reactants and "2H2O" is the product. Also, "-->" is the sign for "yield." The big 2s in front of H2 and H2O are called coefficients. In this case, the first 2 indicates that there are 2 molecules of H2, which also means that there are 4 atoms of hydrogen in the reactant part of the equation. The other 2 signifies that there are 2 molecules of H2O as the product. This means that every molecule of H2O that contains 2 atoms of hydrogen contains 4 hydrogen atoms and 2 oxygen atoms. According to Chemistry Formulas (2005), the
Estimated heat distribution by convection in water
Estimated heat distribution by convection in water Introduction This report assesses the distribution of heat by convection in water to estimate the heat conductivity of water. The transfer of heat from a heating coil to a fluid is conduction but the heat transfer within the fluid is convection. This is basically fluid flow of particles arising from nature, heat, chemical or kinetics. The distribution of heat is assessed with various factors introduced. In this case a magnetic stirrer and a motor. This report presents an estimate of the effect of free and forced convention on the distribution of heat in water. Experimental method The apparatus were arranged as shown in fig. 1. A beaker of five litre capacity was places on a motor, four litres (4L) of cold water was put in a beaker. A heating coil and three thermometers were placed at various depths in the beaker of water and their various distances from the base of the beaker were recorded. Power was supplied to the motor and heating coil and at intervals of four minutes each; the temperatures on all three thermometers were read simultaneously. After four successful readings, the electricity supply was disconnected and the ambient temperature was recorded. This same procedure was repeated twice, the first with a magnetic stirrer and the next time without the magnetic stirrer but the motor operating. Distance from base
Littlebrook Power Station - short report
Littlebrook is an oil-fired power station, which uses oil to produce electricity. The oil is transported by the sea. It is powered by heavy fuel oil this means it has to bring tonnes of oil from other countries. Littlebrook is located on the banks of the river Thames in Dartford. In the 1990s the CEGB was privatised from that came out npower RWE Innogy from that two companies came out international power. RWE then took over which made RWE npower. There has to be lots of work done in the power station like: Finance - the finance department is probably the most important in the power station. Marketing Team - this would include a team which goes to the market to buy and sell the electricity on the market. The company has to also buy electricity from other companies at a cheaper rate so they don't lose profit. The marketing team also have to buy supplies from other countries i.e. at the moment most of the oil in the world is in the Middle East and in Latin America. The company don't have to pay that much for transportation because there are next to the River Thames. In the power station there are about 120 people working this includes the workers the receptionists, catering, security and also the actual worker who are in the power station. In a power station all kinds of people work there. One of the main ones is people like: Security - are there to protect the worker and
Mendel: Extra Biology Credit
Dear Dad, I've been in the Monastary discoving the basic of genetics. I've been experimenting with my garden peas for the past couple of years. The organisms that are used as the original mating in an experiment (tall and short plant) are called the parental generation in abbreviation is the P generation which stands for parent. When I mated the two offsprings in the p generation, the offsprings are in the F1 generation. When I breed the F1 generation I ended up with the F2 generation. For the F1 generation I selected a six foot pea plant and a short pea plant and crossed them. In the F1 generation I noticed that all the offspring were tall and didin't even show short. In the F2 generation I crossed 2 tall pea plants and noticed that 3/4 of the offsprings were as tall as the tall plants in the P generation. I also noticed that 1/4 of the offspring were as short as the short plants in the P generation. I noticed that one trait kept disappearing in the F1 generation. I gave a capital letter to the trait which showed up in the first generation and the small letter to the trait which was hidden in the F1 generation. The trait that appeared in the F1 generation I called dominant and the traits that were hidden I called recessive. I observed that some tall plants crossed with each other showed both and tall and short offspring. I came to the conclusion that an organism may look
Nuclear Fusion as energy provider
For ?-decay, unstable atom emits an ?-particle, this can also apply to ?-decay. To distinguish ?-decay and ?-decay, here is a number of characteristic of each of the decay: relative charge, relative mass, nature, range, material to stop, deflection in electric field and magnetic field. ?-emission ?-emission Relative charge +2 -1 Relative mass 4 0.00055 Nature 2 protons + 2 neutrons (Helium nucleus) Electron Range 5cm 6m Material to stop Paper Aluminium(5mm thick) Deflection in electric field  Slightly towards negative terminal Greatly towards positive terminal Deflection in magnetic field Slightly upwards Greatly downwards As an example, Bismuth can decay into Thallium and Polonium by emitting ?- and ?-particle respectively. For ?-decay of Bismuth: For ?-decay of Bismuth: The example above can show ?-particle is Helium particle while ?-particle is electron. Radioactive decay is different from fission reaction. Radioactive decay Fission . unstable . absorb 1 neutron 2. emit ?/?/?- particle 2. oscillate 3. become other elements 3. unstable 4.Fission (split) 5. give out 3 neutrons Fission reactions differ from radioactive decay both in the way that the reaction must be started and in the type of products that are formed . Radioactive decay is a passive action, while fission is active. For radioactive decay, the atom is unstable;
Investigation to find out whether or not it is correct to call a rubber band elastic.
Elastic band investigation Aim: - to find out whether or not it is correct to call a rubber band elastic. Plan: - The factors affecting the elasticity of a rubber band are: * Downward force applied to the band * The type of rubber the band is made from. * The length of the band * Cross sectional area of band The variable I am going to investigate is the effect of weight on the rubber band. This is a continuous variable. I am going to measure the distance the rubber band has stretched after each amount of weight is placed on it. I am going to keep taking lengths until the band brakes. Pilot test: - To decide what amount of mass to step up in I am going to run a preliminary experiment. I am going to find the elastic limit of three rubber bands. To do this I added weights until the band snapped. Test Number of masses at which band broke 2 3 22 20 25 To work out how many masses to go up in I am going to divide the number of masses at which the band broke into 10 equal pieces. This gives me 2.2, 2.0 and 2.5 as 2 is the average round number I will use this. To make the experiment a fair test I will do the experiment three times to gain a fair average. Each of these times I will also use the same type of rubber band as a different type of rubber could effect how far the band will stretch and therefore my results. I will also try to add the weights gently so that
What effect does substrate have on respiration in yeast?
What effect does substrate have on respiration in yeast? AIM The aim of this investigation is to find out how the rate of respiration in yeast is affected when different respiratory substrates are used. Five different respiratory substrates will be used and the amount of carbon dioxide produced will be measured for each substrate. The five substrates that will be used are glucose, fructose, maltose, sucrose and lactose. HYPOTHESIS Null hypothesis, H0: There is no significant difference between the amounts of carbon dioxide produced by yeast during respiration, regardless of the respiratory substrate used. Alternate hypothesis, H1: There is a significant difference between the amounts of carbon dioxide produced by yeast during respiration, depending on the respiratory substrate used. PREDICTION Natural habitat of yeast is the skin of fruit, which usually contains fructose and glucose and in some cases sucrose. Yeast is also found on malt so it is familiar with maltose as well. Therefore it will be able to secrete the enzymes needed to break down glucose, fructose, sucrose and maltose. However, lactose is present in milk and other dairy products, where yeast does not live. As a result, it is likely that yeast would not have the enzyme, lactase, needed to break down lactose. The table below shows each substrate, the enzyme needed to hydrolyse this substrate and
Case study - Outbreak of food poisoning at scientific conference.
Case Study "Outbreak of food poisoning at scientific conference" In order to investigate the outbreaks described, the following table (table 1) was presented. The table concentrate at the critical points of the outbreak. The range of onset illness was generated in the table as the incubation period of unknown micro-organism. The duration of the reported symptoms from victims was generated as the duration of illness. The temperature at which the sample was held was generated in the table as environment. Table1. Critical points of the outbreak Outbreak title Outbreak of food poisoning at scientific conference Symptoms Abdominal pain, diarrhoea, fever, nausea, vomiting Incubation period 5-48 hours Duration of illness 3-7 days Likely source of the outbreak Cooked meats (ham, roast beef, chicken) Environment 24°C Examined samples Meats left over Laboratory findings Rod, Gram -ve, facultative anaerobe From the critical points given on the table 1, it could be assumed that the micro-organisms that could be involved in this outbreak were Salmonella enterica (S. enterica), Escherichia coli (E.coli) or Campylobacter jejuni (C. jejuni). These micro-organisms are very common cause of food poisoning and they have very similar properties. They are Gram -ve rods. S. enterica and E. coli are facultative anaerobic micro-organisms and they temperature range is 10 ºC -
The theory behind enthalpy changes
The theory behind enthalpy changes Exothermic reactions are most common, however, an important example of an endothermic reaction is photosynthesis in plants, where the energy supplied is from sunlight. Law of conservation of energy: Energy cannot be destroyed or created but only transferred from one form to another. The total energy of a system of reacting chemicals and surroundings remains constant. Enthalpy change is the term used to describe the energy exchange that takes place with the surroundings at a constant pressure and is given the symbol DH. Enthalpy is the total energy content of the reacting materials. It is given the symbol, H. DH = DH products - DH reactants The units are kilojoules per mole (kJmol-1) An exothermic enthalpy change is always given a negative value, as energy is lost to the surroundings. DH = -xkJmol-1 An endothermic enthalpy change is always given a positive value, as the energy is gained by the system from the surroundings. DH = + ykJmol-1. Standard enthalpy changes: standard conditions If we are to compare the enthalpy changes of a various reactions we must use standard conditions, such as known temperatures, pressures, amounts and concentrations of reactants or products. The standard conditions are: A pressure of 100kilopascals (102kPa) A temperature of 298K (25oC) Reactants and products in physical states, normal for the