paper cones investigation

Investigation Report Aim Theory When an object is dropped in air, it accelerates. If it is allowed to drop far enough then it can reach its terminal velocity. This is the maximum velocity of the object during its fall and occurs when the upward force of air resistance acting on the object equals the weight of the object. So at terminal velocity... (P.31, Complete Physics, 1999, Pople, Oxford University Press, ISBN 0-19-914734-5) (P.33, Physics 1, 2000, Cambridge University Press, ISBN 0-521-78718-1) Looking for a formula for air resistance... F = force of air resistance ? = density of air = 1.2kgm-3 c = coefficient of drag for the object / dimensionless A = cross-sectional area of object hitting the air / m2 v = velocity of the object / ms-1 (http://damonrinard.com/aero/formulas.htm) Looking for a formula for the weight of an object... W = m.g W = weight / N m = mass / kg g = acceleration due to gravity, 9.81Nkg-1 (P.55, Physics, 1991, Robert Hutchings, Nelson, ISBN 0-17-438510-2) So putting these formulae together... From the Physics AS course, v = velocity x = displacement t = time so References to the specification Forces and Motion 2821 Forces, Fields and Energy 2824 Aim of your investigation The aim of this work is to investigate the relationship between the time taken for a paper cone to fall and the mass of the cone. Variables

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The advantages and limitations of electron microscopy.

The advantages and limitations of electron microscopy There are two main branches of microscopy that are pertinent to cell biology. These branches arise from the two types of microscope; the light microscope and the electron microscope. The basic principles of light microscopy have been known since circa 17th century, however improvements in lens manufacture in circa 19th century allowed the use of microscopy to be much more practically available and useful. This is increased ability inspired rapid research into both the design of microscopes and the preparation of specimens. However, the light microscope can only magnify objects bigger than 0.2 micrometres; due to its limited resolving powers. This is because it utilises a beam of light. Relatively, light has a long wavelength, this means that when there are two small points close together there is too much refraction and wave front overlap, the eye then only sees one point. This can also be considered in terms of objects "crossing the path" of the wavelength. The smallest wavelength of visible light is 400nm, the diameter of mitochondria is 1000nm, and therefore mitochondria cross the path of the light wave. However ribosomes have a diameter of 22nm, and do not cross the path of the light wave and are therefore not seen by the light microscope. As biologists came to realise these limitations they understood that the

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investigating the relationship between the diameter and the current in a wire at its melting point

Investigation Report Aim Theory Electrical resistance is a measure of the degree to which an object opposes the passage of an electric current. The SI unit of electrical resistance is the ohm. Its reciprocal quantity is electrical conductance measured in siemens. Resistance is the property of any object or substance of resisting or opposing the flow of an electrical current. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit. Some formulae for resistance are where R is the resistance of the object / ? V is the potential difference across the object / V I is the current passing through the object / A (Ref. http://en.wikipedia.org/wiki/Electrical_resistance) where R is the resistance/ ? ? is the resistivity / ?m l is the length of the wire / m A is the cross section area of the wire / m A = ?() = ? where A is area / m d is the diameter / m Putting the formulae together, so (Ref. http://physics.bu.edu/~duffy/PY106/Resistance.html) Aim of investigation The aim of this work is to investigate the relationship between the resistance and the diameter of the wire. Variables Variable Independent / Controlled / Dependent Resistance D Resistivity C Length of wire C Diameter I Prediction Since the theory suggests that So So the resistance should be

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Are mobile phones a health risk?

Abstract In this report I aim to determine whether or not mobile phones pose a risk to our health. I will explain how mobile phone electromagnetic radiation can be perceived as dangerous, with reference to the EM spectrum. I will cite scientific sources of evidence which support both sides of the dispute, and will come to a reasoned conclusion as to how likely it is that mobile phones are a health risk. I will also evaluate the credibility of the sources used to support my conclusions, and list all the sources used throughout in a detailed bibliography. Introduction Mobile phones are becoming increasingly popular in today's world; with around 80 million handsets in Britain, there are now more mobiles than people [1]. They've become an essential part of our existence, in business, in our daily lives and in keeping in touch with our loved ones - however, there is growing concern that this technology is causing serious health problems throughout the population, such as lasting brain damage and cancer. The Media consistently tends to portray mobile phones negatively, fuelling the public's fears and misgivings: this study aims to determine from the scientific evidence whether or not mobile phones present a risk to our health. Main Points How might Mobile Phones be Hazardous to our Health? After studying numerous publications, I have found that if there are concerns about how

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Electrical Hazards.

Electrical Hazards, risks of injury or death arising from exposure to electricity. Electricity is essential to daily life, providing heat and light and powering appliances in homes and factories. It must, however, be treated with great care, because the consequences of an electrical fault can be serious and sometimes fatal. Generally voltages greater than 50 volts can present a serious hazard and currents of more than about 50 milliamps flowing through the human body can lead to death by electrocution. A shock occurs when a "live" part of some device is touched, so that current passes through the body. Its severity depends on many factors, including the body's conductivity (the ease with which electricity passes through it). The conductivity is usually small, but can be increased if the body or clothing is wet. The risk of injury also increases according to the size of the voltage or current, or the duration of contact. There is a risk of electrocution (death by electric shock) if current passes across the heart. For example, if one foot is touching wet ground, the risk is greater if the arm on the opposite side touches a high-voltage source than it would be if the arm on the same side did so. Current passing into the body generates heat, which burns the tissue. Electricity can also present less direct risks. Burns are caused when hot surfaces on electrical appliances are

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Internal Resistance of a cell

Topic: Internal Resistance of a cell Aim: To measure the internal resistance and emf (the potential differences across a voltage Source when no current is flowing) and to observe the combination of cells Hypothesis: The emf of the old cell is less than the emf of the new cell but the internal resistance of the old cell is much greater than the new cell. Introduction: Resistance in electricity, property of an electric circuit or part of a circuit that transforms electric energy into heat energy in opposing electric current. Resistance involves collisions of the current-carrying charged particles with fixed particles that make up the structure of the conductors. Resistance is often considered as localized in such devices as lamps, heaters, and resistors, in which it predominates, although it is characteristic of every part of a circuit, including connecting wires and electric transmission lines. (Britannica.2006) The dissipation of electric energy in the form of heat, even though small, affects the amount of electromotive force, or driving voltage, required to produce a given current through the circuit. In fact, the electromotive force V (measured in volts) across a circuit divided by the current I (amperes) through that circuit defines quantitatively the amount of electrical resistance R. Precisely, R = V/I. Thus, if a 12-volt battery steadily drives a 2-ampere

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Power generation

Introduction: Oil is a liquid fossil fuel and is formed from layers and layers of buried animals and plants that have been under a lot of heat and pressure over a long time. Oil is a non-renewable resource as it cannot be produced on human time frame. Oil is used for many things; it's used for transportation, heating purposes, fuel for electricity generating plants. Fuel is found underground reservoirs. The production of electricity from oil begins with the extraction of oil and ends with the oil burning in boilers and turbines at power plants. Crude oil is removed from the ground by drilling deep wells and pumping it up to the surface. The crude oil is then moved to a refinery (refineries remove a portion of the impurities in the oil, e.g. metals) where it is refined into a number of fuel products: kerosene, gasoline, liquefied petroleum gas (propane). Then this crude oil is moved to power plants by trains, trucks, pipelines or ship. Many methods are used at the power plants to generate electricity from oil. One of the methods is to produce steam by burning the oil in the boilers which is used by a steam turbine to generate electricity. Another common method is to use combustion turbines to burn oil. In a fossil plant, oil, gas or coal is fired in the boiler, which means that the chemical energy of the fuel is converted into heat. Name of Fuel

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Determining Avogadro's Number Lab

Determining Avogadro's Number Lab Data Collection Table 1. Table showing initial mass, final mass and qualitative observation of copper electrodes. Electrode 1 Electrode 2 Initial Mass (g) ±0.005 g 5.77 5.80 Final Mass (g) ±0.005 g 6.27 5.27 Observations The copper electrode is shiny after being placed in copper sulfate. It also appears to have become thicker. The copper electrode is dull after being placed in copper sulfate. It also appears to have become thinner and rusty. Table 2. Table showing current of copper electrodes in 600 second intervals. Time (seconds) ±5 seconds Current (amps - A) ±0.05 A 0 .1 600 0.7 200 0.9 800 .0 Note: As both copper electrodes were placed in a single beaker of copper sulfate, the data obtained for the current is the same for both electrodes. Thus, the "Current" column in Table 2 represents the current of both copper electrodes. Table 3. Table showing voltage used during the experiment. Voltage (volts) ±0.5 V 6 Data Processing Moles: Number of moles Electrode 2, which lost 0.53 grams after being placed in copper sulfate, contains approximately 0.00834 moles of copper. Uncertainty of moles Uncertainty of mass = Uncertainty of initial mass + Uncertainty of final mass Uncertainty of mass = 0.005 g + 0.005 g Uncertainty of mass = 0.01 g Percent uncertainty of mass = Percent

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Falling parachute experiment

Falling Parachute Experiment Aim To investigate the motion of objects for which the air resistance is quite large. Introduction Free fall is a special type of motion in which the only force acting upon an object is gravity. Objects that are said to be undergoing free fall, are not encountering a significant force of air resistance; they are falling under the sole influence of gravity. . Under such conditions, all objects will fall with the same rate of acceleration, regardless of their mass [1]. W = mg where W=weight (N); m= mass of object (kg); g=gravitational acceleration (m/s2). The amount of air resistance depends upon the speed of the object. A falling object will continue to accelerate to higher speeds until they encounter an amount of air resistance that is equal to their weight. The object will accelerate to higher speeds before reaching a terminal velocity. Thus, more massive objects fall faster than less massive objects because they are acted upon by a larger force of gravity; for this reason, they accelerate to higher speeds until the air resistance force equals the gravity force [1]. Method The apparatus used in the experiment are a plastic bag, scissors, a set of 5 paperclips, a ruler, stopwatch or wristwatch with ability to read to at least 0.1 s, notebook and pencil. Firstly, the plastic bag was cut into a 15x15 square. Next, strings were tied through

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Investigate four factors that may affect the strength for electromagnets: the number of turns, the size of the current, the nature of the current (a.c. or d.c.) and the distance between the sensor and the magnet.

Strength of electromagnets Design Research question Investigate four factors that may affect the strength for electromagnets: the number of turns, the size of the current, the nature of the current (a.c. or d.c.) and the distance between the sensor and the magnet. This experiment will be divided into 4 parts investigating each of the 4 factors. For each part, the independent variable is one of the 4 conditions (the number of turns, the size of the current, the nature of the current (a.c. or d.c.) and the distance between the sensor and the magnet). The dependent variable is the strength received by the sensor. The controlled variables will be the room temperature and the other three factors. Materials and methods The materials I used are a magnet, a long copper wire, an ammeter, a sensor, power supply, a thermometer, a graphical calculator and a rheostat. Part 1: Number of turns Measure the room temperature and record as 't'. 2 Set the power supply as a.c., set the rheostat at position A and keep the sensor 5cm from the magnet. Keep these three conditions constant throughout the whole part. 3 Connect the circuit as the diagram showed. 4 Twine the wire on the magnet with 20 turns. 5 Turn on the switch and record 5 successive readings on the graphical calculator as 'X1 T' (since the reading changes all the time) 6 Turn off the switch and change only and increase

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