The effects of disinfectants and antibacterial soap on bacterial growth
The effects of disinfectants and antibacterial soap on bacterial growth Abstract The effects of various disinfectants and one brand of antibacterial soap on bacterial growth were examined. Different cleaners containing either ethanol, sodium hypochlorite, or triclosan as a primary ingredient were added to culture tubes containing bouillon broth and bacteria taken from the classroom. Bacteria from each tube were regrown on agar plates to determine whether the disinfectant or soap, which had been added to the bacteria's rood source. was effective. Under the conditions of the experiment, all cleaners tested proved satisfactory in killing the bacteria found in the classroom. Introduction. Hospitals are supposed to be clean, right? All bacteria living on countertops and on other surfaces arc supposed to be killed with routine applications of potent cleaners to provide a sanitary environment for patients. But would it be possible for the disinfectants used in hospitals to be less effective than the manufacturing companies claim'? Our doubts were raised by a previous experiment that had been performed on different brands of soap, which had indicated that not all soaps were as effoctive as they claimed [1]. Clearly, our question was a pertinent one. At the very least, the patients and doctors might be concerned if going to the hospital meant being exposed to a whole range of
GCSE Bioligy Case Sudy - MRSA
Is going to hospital too much of a risk due to the outbreak of MRSA? Contents Page * Introduction 1 * What is MRSA? 2 * How does MRSA reproduce? 2 * Why is MRSA resistatant to most antibiotics? 3 * How do antibiotics work? 3 * How can MRSA be prevented? 3 * How does MRSA harm someone? 4 * What are the symptoms of MRSA? 4 * MRSA in hospitals 5 * Arguments against going to hospital 5 * Arguments In favour of going to hospital 5 * Evaluation of the evidence 6 * Conclusion 6 * Alternative Conclusion 6 * Bibliography 7 Introduction In this
Methods of Removal of Hardness in Water
Methods of Removal of Hardness in Water Removal of Temporary Hardness By boiling the hard water Temporary hardness in water can be easily removed by boiling. On boiling, calcium/magnesium bicarbonate decomposes to give calcium/magnesium carbonate, which is insoluble in water. Therefore, it precipitates out. By the addition of slaked lime (Clark's process) In Clark's process, slaked lime, Ca(OH)2 is added to temporary hard water. Insoluble calcium carbonate precipitate out and no longer produce hardness. The methods used to remove permanent hardness given in the next section can also be employed to remove the temporary hardness. However, the above methods cannot be used to remove the permanent hardness. Methods to Remove Permanent Hardness By the addition of washing soda (sodium carbonate) Calcium and magnesium ions present in hard water react with sodium carbonate to produce insoluble carbonates. The water now contains soluble and harmless sodium salts. Calgon process Calgon is a trade name of a complex salt, sodium hexametaphosphate (NaPO3)6. It is used for softening hard water. Calgon ionizes to give a complex anion: The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon. This results in the removal of calcium and magnesium ions from hard water in the form of a complex with
The effects of shade from trees on plants below
The Effect Of Shade From Trees (On plants below) The effects of shade from trees on plants below Introduction A collection of living things together at the same place and time is called a Habitat. The main purpose of a habitat is to provide and adequate food supply, a comfortable place to breeding/reproduction to take place and to provide a certain degree of shelter. Examples of various habitats are: * Forests and woodland/ trees * Bushes and shrubs * Ponds/ lakes * Sand dunes * Grassland * Rocky shores * Mossy brick walls Apart from where the habitat is situated, there are also 5 other key factors that affect the living things in a habitat. These are: . Climate: which includes variation in Temperature, the amount of rainfall, the light intensity and wind variation. 2. Biotic: Interaction of living things e.g. food chains/ webs 3. Humans: pollution and insecticides are used which effect the environment. 4. Soil: Variations in soil type lead to certain living things having to live in certain areas 5. Shape of the land and aspect: certain areas of land would not be suitable for all living things because of various obstacles. A woodland habitat Within a woodland habitat the main dominating organisms are the trees. The reason for their domination apart from the fact that they are usually larger than most other wildlife is due to the fact that trees have
should cannabis be legal, YES & NO
Should Cannabis be Legalised? Yes... No... Legal Cannabis would promote responsible use and safe supply and would stop many people's futures being needlessly destroyed Legalisation would encourage use of cannabis and other drugs, creating more problems and increasing the profits of drug barons. * There are at least 21/2 million (perhaps 7 million) cannabis users in the UK. * More police are needed, with greater powers to stop this widespread flaunting of the law. * People convicted of drug offences have their future prospects massively hampered. * People who choose to break the law must accept that they will be severely punished for doing so. * Cannabis is often contaminated with inert or toxic components which cause more harm than the cannabis. A legal supply would be pure and therefore safer. * Pure cannabis still has dangers. * Prohibition alienates a huge number of youths. * Most parents disapprove of all drug use - legal or not. * Legalising does not mean glamorising - cannabis use should still be discouraged even if it were legal. * Legalisation could make cannabis socially acceptable, and so encourage use. * Countries which have experimented with decriminalisation have not encountered massive increases in use. * Legalisation could encourage use of cannabis, which in turn could encourage the use of more dangerous drugs such as ecstasy. * Minors can
Chemistry coursework - Fuels
Planning Aim In this investigation I will have to find out which of the alcohol fuels: methanol, ethanol, propanol and butanol, is the best. The 'best' one will be the one which creates the most energy whilst burning. Introduction and prediction A fuel is a substance burned for heat or power. The best type of fuel is one that: can be transported safely without the worry of it catching on fire, gives out a lot of heat for a certain mass, does not cost very much, lights quickly, burns slowly, is safe to use and does not give off any form of polluting gases. When burning alcohols, as I am going to do in this investigation, the reaction is exothermic as heat is given out. Breaking the bonds of the original alcohol by burning requires energy-it is endothermic, making the bonds of the new products of burning the alcohol ie carbon dioxide and water gives out energy-it is exothermic. I predict that Butanol will require the most energy as it has the most bonds holding the carbon, oxygen and hydrogen atoms together. Propanol will require the second largest amount of energy, Ethanol the third and Methanol the least amount of energy to break these bonds. Methanol CH3OH Ethanol C2H5OH Propanol C3H7OH Butanol C4H9OH Pentanol C5H10OH Therefore I predict that Methanol will be the 'best' fuel, followed by Ethanol, then Propanol and the worst fuel will be Butanol. Apparatus
Biology notes
AQA GCSE Biology Unit 2 Summary Notes 2.1 Animal and Plant Cells Cells * Cells are the smallest unit of life. * All living things are made of cells. * Most human cells, like most other animal cells, have the following parts: o nucleus o cytoplasm o cell membrane o mitochondria o ribosomes * Plant cells also have: o cell wall o chloroplasts o permanent vacuole What do these structures do? * Nucleus - controls the activities of the cell. * Cytoplasm - where most of the chemical reactions take place. * Cell membrane - controls the passage of substances in and out of the cell. * Mitochondria - where most energy is released in respiration. * Ribosomes - where protein synthesis occurs. * Cell wall - strengthens plant cells. * Chloroplasts - absorb light energy to make food in plant cells. * Permanent vacuole - filled with cell sap in plant cells. Other facts: * The chemical reactions inside cells are controlled by enzymes. Examples: o Enzymes for respiration are in the mitochondria. o Enzymes for photosynthesis are in the chloroplasts. o Enzymes for protein synthesis are on the ribosomes. * Cells may be specialised to carry out a particular function. Examples: Tissues, organs and systems * A tissue is a group of similar cells carrying out a particular function. * An organ is a group of different tissues carrying out a particular function. *
Analysis of anaemia.
Anaemia Problem Anaemia is a condition resulting from below- normal levels of haemoglobin in the red blood cells. Haemoglobin in the blood is responsible for carrying oxygen to the rest of the body. Anaemia may be due to loss of blood from heavy menstrual periods, from internal bleeding caused by a peptic ulcer, or from haemorrhoids. A healthy person whose diet contains plenty of iron and vitamins can produce large amounts of new blood. However, if your diet is inadequate, even small, persistent losses of blood may cause anaemia. There are several kinds of anemia. Iron-deficiency anaemia can develop in those who do not have enough iron, which is an essential ingredient of haemoglobin. Lack of Vitamin B-12 or folic acid can result in Vitamin B-12 deficient anaemia and folic acid deficient anaemia. Hemolytic anaemia occurs when red blood cells are destroyed more quickly than they can be replaced. The symptoms of anaemia include fatigue, weakness, fainting, breathlessness, and heart palpitations. Aplastic anaemia is a rare disease which affects mostly young men. 2 to 6 people per million worldwide develop this disorder annually but it affects mostly people in the Orient. A variety of associations have been made in the attempt to find a specific cause, but no one cause can be identified. Treatment must be given straight away after diagnosis to avoid fatality. Patients
Investigation in resistance in wires
Investigating Resistance in Wires Aim In this investigation I will be looking into the theory of resistance and current in wires; this theory is called Ohms Law. By doing the experiments I will be hoping to prove Ohms law correct, and testing to see if it remains constant as the voltage, and wire lengths vary. Related Theory Resistance is measured in ohms (), resistance can be calculated by using the formula V = I × R V = voltage measured in volts (V) I = current measured in amps (A) R = resistance measured in ohms () This is the formula called Ohms Law. Ohms law is the relationship between voltage, current and resistance. For a metal conductor at a constant temperature the current is directly proportional to the voltage. This means that if the current increases the voltage will also increase in the same proportion. For example: If a cell provides a voltage of 1 volt and the circuit has a resistor of 1 ohm connected to it an ammeter would read 1 amp. If the cell was replaced with a 2 Volt cell the ammeter would read 2 Amps. Resistance is caused by electrons bumping into ions. If the length of the wire is doubled, the electrons bump into twice as many ions so there will be twice as much resistance. If the cross-sectional area of the wire doubles there will be twice as many ions and twice as many electrons bumping into them, but also twice as many electrons getting
Rates of Reaction
Introduction In this investigation I am investigating the reaction between hydrochloric acid and calcium carbonate (known as limestone). The rate of reaction is basically the speed a reaction takes place- meaning how long it occurs for. Chemical reactions only occur when reacting particles collide with each other with sufficient energy to react. The minimum amount of energy that causes them to react is called the activation energy - simply because it activates the reaction. There are many variables that need to be taken under consideration when measuring the rate of reaction. These can include catalysts, surface area, temperature or concentration of the liquid. In this case the dependant variable is the concentration of the liquid. These variables can either decrease or increase the rate of reaction. Theoretical Background When a reaction takes place it has to overcome a minimum energy barrier known as the Activation Energy. If the particles collide with less energy than the activation energy then nothing worth noting happens. "You won't get a reaction unless the particles collide with a certain minimum energy called the activation energy of the reaction." (Taken from www.chemguide.co.uk). Only those collisions, which have energies equal to or greater than the activation energy result in a reaction taking place. The reason why collisions have to overcome the
