refraction experiment
REFRACTION EXPERIMENT Aim: To study the phenomenon of refraction of light by using a glass block. Theory: Light is one of the most fundamental energy forms and an understanding of several of its properties is essential to any understanding of science. In this investigation we would be seeing the different phenomenon of refraction of light. Refraction is a change in the direction of radiation that occurs when it crosses the interface between two media in which the radiation travels with different speeds. The radiation undergoes a change in speed, in wavelength, and in direction. These are a few common terms in relation to refraction of light: > Reflection: the process by which radiation that strikes a surface separating two media of different densities is in part or in whole turned back into the medium from which it originated. The radiation rebounds from a barrier in its path without a change in speed. > Normal line: A line perpendicular to the surface at the point where a ray of light strikes. > Incident Ray: A ray which impinges upon a surface. > Refracted Ray: a ray that has changed direction after crossing from one media to another, in which the speed is different. > Emergent ray: the light ray leaving a medium in contrast to the entering or incident ray. > Angle of incidence: the angle between the incident ray and a normal. > Angle of refraction: the angle
Investigating how the Length of a Pendulum affects its Period
Investigating how the Length of a Pendulum affects its Period Plan: Before this experiment I did some preliminary experiments here I tested whether the angle and height at which a pendulum is dropped from affects its period and whether the weight of the pendulum bob affects its period. I found that in both cases, no matter how big or small, these factors did not affect the pendulums period. My results are at the bottom of the page. But you can see from my results in the table, that it does not matter what the weight is, or as a matter of fact the angle at which the pendulum starts, the period stays the same. In my experiment there are variables that I must keep the same. For example there is the weight of the pendulum bob. I have decided to use a medium sized bob, which when was weighed it was 39.9g. Even though my results showed that it did not matter what the weight was I will try to pick and use the same bob through out the experiment. Next I must make sure that I do not push the metal bob when the first period starts as then it would give it extra energy that would not make a fair test. The force of gravity will stay the same on earth whenever I do the experiment and so this does not need to be worried about. Amplitude (or the angle at which the bob is released at) does not matter, as proved earlier. I must also ensure that the corks holding the string are held
The aim of this experiment is to investigate what effect the surface area of a parachute has on the terminal velocity of the parachute.
Aim: The aim of this experiment is to investigate what effect the surface area of a parachute has on the terminal velocity of the parachute. Theory: When a parachutist first jumps of a plane, he has very little air resistance and minimal velocity. So as he gains speed and this increases his air resistance, this in turn reduces his acceleration. Until the air resistance is balanced by the speed. But as the parachutist is falling very fast he opens his parachute, so his surface area increases a lot and because of the parachute air resistance of the parachutist is increases and this means that the velocity has to balance the air resistance and therefore decreases. When the air resistance and the velocity balance out, maximum velocity is achieved and there is no further acceleration, this is called "Terminal Velocity" Variables: There are different variables that can be changed in this experiment. Variable Method How will it affect the terminal velocity? . Surface Area This variable can be changed by making a large parachute at first and then cutting the size down. Terminal velocity should be larger as the Surface Area becomes smaller. This should be because there will be less Air Resistance when there is less of the parachute to trap the air. 2. Mass The mass of the parachute can be increased by adding an extra weight. The more the weight of the parachute is the
green house effect
GREEN HOUSE EFFECT The greenhouse effect, first discovered by Joseph Fourier in 1824, and first investigated quantitatively by Svante Arrhenius in 1896, is the process in which the absorption of infrared radiation by an atmosphere warms a planet. Without these greenhouse gases, the Earth's surface would be up to 30 °C cooler. The name comes from an incorrect analogy with the way in which greenhouses are heated by the sun in order to facilitate plant growth. In addition to the Earth, Mars, Venus and other celestial bodies with atmospheres (such as Titan) have greenhouse effects. In common parlance, the term greenhouse effect may be used to refer either to the natural greenhouse effect, due to naturally occuring greenhouse gases, or to the enhanced (anthropogenic) greenhouse effect, which results from gases emitted as a result of human activities (see also global warming, scientific opinion on climate change and attribution of recent climate change). The Basic Mechanism The Earth receives energy from the Sun in the form of radiation. To the extent that the Earth is in a steady state, the energy stored in the atmosphere and ocean does not change in time, so energy equal to the incident solar radiation must be radiated back to space. Radiation leaving the Earth takes two forms: reflected solar radiation and emitted thermal infrared radiation. The Earth reflects about 30% of
What factors affect the resistance of Ni-Chrome wire?
What factors affect the resistance of Ni-Chrome wire? Hypothesis I am investigating what affects the resistance of Ni-Chrome wire. The main variables I could test are the thickness of the wire, the length of the wire and the temperature of the wire. I am going to investigate how the length of wire affects the resistance of Ni-Chrome wire. What is Ni-Chrome wire? Ni-Chrome wire (NiCr60) is a Nickel and Chrome Alloy it consists of the following elements nickel: 57-58%, chromium: 16%, silicon: 1.5%, iron: Balance. Ni-Chrome wire is commonly used as a resistance heater for cutting foam (Styrofoam, polyurethane, etc.) fabrics, and a variety of other materials. What is resistance? Resistance is the electrical term used to describe the property that various materials have to restrict or slow down the flow of electricity or current. Electrical resistance is low in most metals and high in most non-metallic materials. Electrical resistance is measured in ohms (?). I am going to use this formula calculated by George Ohm to calculate resistance. Voltage / Current = Resistance V V / I = ? I R Diagram to show the movement of electrons through a wire I predict that the longer the length of wire the more resistance will occur. This is because the longer the wire the more atoms present consequently this increase the amount of times that the electrons
As part of my AS physics coursework I went on a trip to Queen Elizabeth Hospital. The purpose of this trip was to find out the physics involved in Hospital equipment, which is used on patients
Introduction As part of my AS physics coursework I went on a trip to Queen Elizabeth Hospital. The purpose of this trip was to find out the physics involved in Hospital equipment, which is used on patients. I learnt about three different areas where physics is involved. I learnt how physics is involved in Nuclear Medicine, Radiotherapy and Ultra Sound. I will discuss briefly about how physics is used in Nuclear Medicine and I will discuss in greater detail how physics is involved in Ultra Sound. Nuclear Medicine Nuclear physics involves looking at the nucleus of an atom. It involves injecting a highly radioactive material into the body and allowing it to decay. There are positives and negatives in this because nuclear medicine can be used for diagnosis, which can determine functions of an organ or can for simple therapy. On the other hand though radioactive materials are not good for you and so if diseased tissue comes in contact with you then it can cause problems. Using radioactive sources can kill of tumours though. It travels only shallowly into the body and can kill of all the cancerous cells. The unfortunate thing is that it can also kill of healthy tissue. What Is Ultra Sound? Ultra sound is sound with a frequency of over 20,000 Hz, which is a very high limit of human hearing. So therefore humans have a lower limit of hearing and so cannot hear ultrasound.
Factors Affecting The Resistance Of A Metal Wire.
Helen Roberts 10P March 2003 Physics AT1 PLANNING Factors Affecting The Resistance Of A Metal Wire . Investigate some of the factors that affect the resistance of a metal wire. The current and voltage will be measured and then V = IR will be used to calculate the resistance. The potential divider circuit produced better results in the investigation into how resistance depends on the number of identical resistors connected in series, so this circuit will be used for this investigation, too. Variables and Constants 2. Possible variables include the length of the wire, the diameter of the wire, the material of the wire and the temperature. The chosen variable is length of the wire. Because this is the chosen variable, all of the others must be kept constant. The graph I will plot will be the length of the wire (in cm) against the resistance (in ?). Trials 3. Trial using a short length and a long length (10cm and 60cm) of each of the three types of wire. The three types of wire are as follows, copper 0.274mm, nichrome 0.274mm and nichrome 0.457mm. The voltage and current will be measured and the resistance calculated (using V = IR). The wire that has the largest variation between the two measurements will be used, to provide the best results possible. Preliminary Work 4. Copper wire - 0.247mm diameter Length Current (A) Voltage (V) Resistance (?)
Are mobile phones dangerous? Research Project.
Are Mobile Phones Dangerous? Introduction I am looking at ‘Are mobile phones dangerous?’ The case study has some relevance to the current news topics because the findings have been made public and people are always asking ‘are there any risks’, as you will find out there are many theories and supposed evidence, that may or may not be reliable. In this study I will be looking for a correlation between mobile phone usage and fertility in men, increased risk of brain tumours and other negative side effects such as concentration levels. Background information: (information from http://www.vodafone.com.au/personal/aboutvodafone/healthmobilephonetechnology/howdoesthemobilephonesystemwork/index.htm ) Mobile phones use radio waves however some have a higher frequency so can be classed as microwaves. Radio waves are used for communication. Long wave radio has lengths of about 1km. Mobile telephones are two-way radios. When you talk into a mobile telephone, it picks up your voice and converts the sound to radiofrequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station. The base station then sends your call through the telephone network until it reaches the person you are calling. When you receive a call on
The Life Of A Star
The Life of Star Space may seem empty, but actually it is filled with thinly spread gas and dust. This gas and dust is called interstellar medium. The atoms of gas are mostly hydrogen which is H2, and the gas atoms are typically about a centimeter apart. The dust is mostly microscopic grains and combines only a few percent of the matter between stars. The dust is mostly carbon and silicon. In some places, this interstellar medium is collected into a big cloud of dust and gas known as a nebula. This is the birthplace of stars because the gas and dust is what makes up a star. Small Stars: Stage 1- Stars are born in a region of high density which is located within the Nebula, and condenses into a huge sphere-like shape of gas and dust and contracts under its own gravity within a central pull. Stage 2 - A region of condensing matter will begin to heat up and start to glow forming a Protostar. If a protostar contains enough matter of hydrogen the central temperature reaches 15 million degrees centigrade. Stage 3 - At this temperature, nuclear reactions in which hydrogen fuses to form helium will start. Stage 4 - The star begins to release energy, stopping it from contracting even more and causes it to shine. This means that it is in its main sequence in its life as a star. Stage 5 - A small star will be remaining in its main sequence for about 10 billion years, until all
resistance of a wire
Aim The aim of this coursework is to investigate how the length of a constantan (18SWG) wire affects the resistance in a circuit. Preliminary Testing Before I can conduct the experiment I need to investigate further into what I am going to do for the investigation. By doing the preliminary testing I can find the easiest and the best method of doing the experiment. I can also make any alterations to the investigation. The first problem I had was the material that I was going to use as a conductor. I decided to choose constantan wire because it is cheap and it is easily found. Another reason for choosing this was because the resistivity was not that small or large to work with. The table below shows the possible materials we could have used. Material Resistivity/m Silver Copper Aluminium Iron Constantan Mercury Germanium Alumina Pyrex Fused Quartz The next decision I had to make was the type of constantan wire we could have used. I chose to use 18 SWG because its diameter was not to small and not to large. I had other alternatives as well the table below shows this. S.W.G 6 8 20 22 24 26 28 30 32 34 36 38 40 Diameter (mm) .62 .25 0.91 0.71 0.56 0.46 0.38 0.32 0.27 0.23 0.19 0.15 0.12 Now that I have decided on my apparatus I now need to work on the factors. There are many factors that could be taken in to account. I
