"Examine the impact that weathering has had on human activity."
Teacher: Mr Lee, Physical Geography, Joshua Malina 11/12/04 Essay title: "Examine the impact that weathering has had on human activity." Weathering has impacted human activity in a variety of ways. There are both positive and negative aspects of the result of weathering. Firstly, the negative impacts are to be discussed. Weathering often seems to be at a higher rate in urban areas than that of rural areas due to the large volumes of gases and pollution given out by industries and vehicles. When coal and oil are burnet sulphur dioxide is releases and when it combines with water vapour in the air dilute sulphuric acid is the product. Nitrogen oxides combine in a similar way to produce nitric acid. The result is acid rain. The acid rain chemically weathers materials away by decomposing the minerals. London is widely known for burning large doses of fossils fuels increasing the amount of acid rain. This rain has then fallen on buildings such as St. Paul's Cathedral and increased chemical weathering leading to deterioration on its surface. Also, if cracks and joints present will have allowed this rain to enter and chemically weather there as well as on the surface. This chemical weathering has also been enhanced due to the extremely large presence of birds in the area, particularly pigeons whose faeces contribute to the chemical weathering. Very recently this has had
I want to find out if the concentration of the Hydrogen Peroxide affects the speed at which the potato gives off gas.
Catalase Investigation Aim: * I want to find out if the concentration of the Hydrogen Peroxide affects the speed at which the potato gives off gas. Planning Enzymes like catalase are protein molecules that are found in living cells. They are used to speed up reactions within the cell, and so are biological catalysts. Catalysts speed up reactions but they are not changed during the reaction. Enzymes only work on one specific type of substrate that means that there is only one kind of substrate that will fit into the enzyme's active site. Most enzymes optimum working temperature is 37°C (body temperature). Catalase is found in food such as potato that I will be using in my experiment. They are all very specific as each enzyme is used for different jobs. Catalase is used for removing Hydrogen Peroxide from the cells. Catalase is used to speed up the decomposition of the Hydrogen peroxide into water and oxygen. Preliminary experiment First of all I did a preliminary experiment, when we picked 15 potato chips at random and cut them down to the same length using a razor blade, making them even. I then set up the equipment as shown below and injected the hydrogen peroxide solution, and timed how long it took for 1ml of gas to be displaced as the H2O2 is attacked by the enzymes in the potato. ? Fig 1. Equipment setup To do this I will use the following: * * Potato
In this investigation I intend to explore the one of the factors that affects the rate of reactions. My research from textbooks and the Internet suggests that this depends on several factors; temperature, pressure, pH and concentration.
In this investigation I intend to explore the one of the factors that affects the rate of reactions. My research from textbooks and the Internet suggests that this depends on several factors; temperature, pressure, pH and concentration. After research and careful consideration, in my experiment I am going to investigate how a change in temperature could affect the rate of reaction. Using the enzyme in potatoes (peroxidase) reacting with hydrogen peroxide. Rate of reaction increases by: * An increase in temperature * An increase in concentration * An increase in surface area * A catalyst increases the rate but doesn't take part in the reaction The collision theory is when particles of substances collide with each other and there is a reaction. The higher the temperature the more energy the particles have for a faster reaction, more likely that the enzymes/substrates with collide an lock. An increase in temperature increases reactions rates because there is more heat energy in the particles therefore the collisions happens faster. Enzymes work slower at low temperatures because the movement of particles is slower. Molecules have less energy to collide; enzymes and substrates don't find each other and lock. Each enzyme works most effectively at a certain temperature called the optimum temperature. Which is around 50?C, but over this temperature the enzyme rapidly
investigate the effect of carbon dioxide concentration on the rate of photosynthesis.
7/07/2004 Bilawal Ajmal Khan 10A H/W/K Science Investigation Aim: to investigate the effect of carbon dioxide concentration on the rate of photosynthesis. Scientific knowledge: The Elodea (Canadian pondweed) makes bubbles of oxygen when it photosynthesises. The faster it photosynthesises the faster it makes oxygen. The plant uses dissolved carbon dioxide. This can be made by adding hydrogen carbonate solution to the water. The factors which can effect how quickly a plant can make food by photosynthesis include the following. * Carbon dioxide concentration - this can be simulated by changing the volume of hydrogen carbonate solution added to the water. At low concentrations of carbon dioxide the rate of photosynthesis is very slow. As you increase the concentration of carbon dioxide the plant can make food faster and faster. There is a limit however. There comes a time when adding more carbon dioxide does not increase the rate of photosynthesis. The plant is making food as fast as it can under the conditions. * Light intensity - this can be altered by either changing the brightness of the bulb or by moving the bulb further and further away from the plant. Plants need light energy in order to make food. The more light they have the faster they can make food.
Investigating the enzyme 'Catalase'
Year 11 Coursework: Investigating the enzyme 'Catalase' AIM To look at Hydrogen Peroxide (H2O2) being broken down into H2O and Oxygen (O2). We will also investigate the factors that change the rate of reaction. MATERIALS Scalpel White tile 30cm clear plastic ruler Test tubes & rack Stopclock 0ml measuring cylinder 2ml pipette H2O2 Cylinder of potato Goggles Cloth SAFETY The hydrogen peroxide is toxic, and is a bleaching agent therefore if it is spilled it must be cleaned up straight away. You must wear safety goggles to protect your eyes. The scalpel is dangerous, it is very sharp so you must not run and also be very careful while handling a scalpel. METHOD (pilot experiment) ) We will measure out the desired amount of H2O2 and pour it into a test tube 2) We mark and cut out the desired amount of potato with a scalpel. 3) Every 4 minutes we will measure the height of froth produced, to 1 decimal point, from the meniscus. 4) Record results 5) Plot a graph of results We will carry out a pilot experiment to find the best lengths of potato to use for the real experiment. FAIR TESTING To make this a fair test I will: * Monitor the room temperature * Use the same volume of H2O2 & same pH * Same batch/age/brand and freshness of potato * Same diameter of potato * Same ruler * Same person measuring each time, from the same level RATE OF REACTION If we
Rates of Reaction between hydrochloric acid and marble chips
GCSE Coursework Science Rates of Reaction Chantal du Thoit Candidate Number: 0002 01/08/2005 Table of Contents ) Planning 2 a) What I'm going to do. 2 b) Scientific factors and theorems that affect my plan. 3 c) Apparatus I'm going to use. 4 d) Preliminary Work 5 e) Graph to show figure 1 results 7 f) Prediction 8 2) Method 9 3) Results 10 4) Evaluation 12 5) Conclusion 13 ) Planning a) What I'm going to do. I am going to investigate the rate of reaction between hydrochloric acid and marble chips. I am going to measure 5g of different sized Marble Chips and six different concentrations of Hydrochloric Acid. I will then put the chips into each concentration. They will then react to produce carbon dioxide and water. It is at this point when I start timing how long it takes for the water in the 50cm3 cylinder to be replaced by a gas. b) Scientific factors and theorems that affect my plan. I read a book 'GCSE Chemistry' that states that reaction rates are explained perfectly by Collision Theory - the more collisions there are the higher the rate of reaction. I also read an Internet article that can be found at www.gcsescience.com. It stated that a chemical reaction could only occur between particles that collide (hit each other). Particles could be atoms, ions or molecules. In order for the particles to react with each other, they need to have a
sodium thiosulphate
Investigation: How does the concentration of the acid affect the rate of reaction? The aim of this investigation is to test how concentration affects the rate of reaction. My prediction for my investigation is that the higher the concentration, the faster the reaction will be. My reason behind my prediction is: * The higher the concentration, the more particles there are which will collide with enough energy to overcome activation energy, which is explained as the collision theory. Collision theory explains how chemical reactions occur and why rates of reaction differ. For a reaction to occur, particles must collide. If the collision causes a chemical change it is referred to as a fruitful collision. For a reaction to occur, the reactant particles must collide. Only a certain fraction of the total collisions cause chemical change; these are called successful collisions. The successful collisions have activation energy at the moment of impact to break existing bonds and form new bonds, resulting in the products of the reaction. Increasing the concentration of the reactants and raising the temperature bring about more collisions and therefore more successful collisions, increasing the rate of reaction. When a catalyst undergoes collision with the reactant molecules, less energy is required for the chemical change to take place, and hence more collisions have sufficient
The Importance of Water in Living Organisms
Matthew Bradfield The Importance of Water in Living Organisms Water has importance inside cells and externally. This may be because it has interesting chemical and physical properties; it can be found naturally in all three of its states. However its molecules are bonded together by hydrogen bonds, this brings up its melting and boiling points, i.e. its boiling point would be -120¢ªC rather than 100¢ªC. Also because it contains slightly negatively charged oxygen atoms and slightly positively charged hydrogen atoms making it polar. Water has been called a universal solvent because of it polarity. This means it can easily ionise substances, many compounds, whether ionic, polar or covalent will dissolve in it, therefore more reactions take place while in solution with water. Often in organisms substances must be in solution and water is the solvent. Plants can only obtain mineral salts in solution and human digestion will only dissolve soluble foods, meaning large starch molecules must be broken down into soluble sugars. Also many organisms living in water spend most of their time underwater, yet they require oxygen to respire, and as water is such a good solvent the required oxygen gas is dissolved in the water. Water is the most abundant component in any organism, the lowest is 20% in seeds, while jellyfish are 99% (hence the transparency). It plays vital roles in
To determine the water potential of a potato tuber cell using varying salt solution.
Aim To determine the water potential of a potato tuber cell using varying salt solution. Introduction Osmosis is the diffusion of water molecules from a region where it has higher water potential to a region where it has lower water potential through a partially permeable membrane1. As osmosis is a type of diffusion the same things that affect diffusion have an effect on osmosis some of theses things are: * The concentration gradient - the more the difference in molecules on one side of the membrane compared to the other, the greater the number of molecules passing through the membrane and therefore the faster the rate of diffusion2. * The surface area - the larger the area the quicker the rate of diffusion * The size of the diffusing particles - the smaller the particle the quicker the rate and polar molecules diffuse faster than non-polar ones3. * The temperature - the higher the temperature the more kinetic energy the particles have and so the faster they move. From the diagram4 we can see the process of osmosis in a simple expression. On the right side there is pure water, which has the maximum water potential of 0. Water potential is the pressure created by water. As you can see from the diagram the pure water is pushing its way through the semi permeable membrane at a high pressure. This is its water potential. Water potential is measured in kilopascals (kPa)
To investigate the relationship between Angular Acceleration and Torque.
Circular Motion Practical - UB Physics Assessment 1 Aim: To investigate the relationship between Angular Acceleration and Torque. Hypothesis: Angular Acceleration will be proportional to torque ( ??????) according to the equation ????I? Independent Variable: ????Torque : Torque was changed by varying both F and r in the formula ????Fr . Force is varied by changing the hanging mass and therefore the force due to gravity. The radius (r) is varied by using different drive radii (shown in the method diagram), ie. applying the force due to gravity to the different sized rims underneath the cylinder being accelerated. Dependant Variable: ????Angular Acceleration : A cylinder on a low friction axle is accelerated by the independent variable - torque. The measurements taken are the velocity at the rim and the diameter of the cylinder (to find r). Variables to be controlled: -Radius of velocity measurement. The radius from the centre of rotation to the rim which the ticker tape was attached to was a constant 0.124m. Velocity measurements derived from the ticker tape therefore exist at this radius, so it is used to calculate angular velocity ?=v/r. -Radius of torque application. The radius from the centre of rotation to the rim which the force was applied to was varied between three values, 0.0153m, 0.0252m, and 0.0352m. These values are used calculate torque ?=Fr
