The Journey of a carbon atom.
THE JOURNEY OF A CARBON ATOM BY APRIL GRAY THE JOURNEY OF A CARBON ATOM Carbon atoms cycle through the earth and its biosphere. The carbon atom is part of a carbon dioxide molecule (co2) in the atmosphere. Carbon dioxide makes up less than 0.05% of the atmospheric gases. Some of the other major gases are nitrogen (N2), hydrogen (H2), oxygen (02) and water vapor (H20). Carbon atoms are absolute essential to life on earth. A carbon atom was drifting in the atmosphere when it descended down upon a colorful plant. As it glided over the top of the plants flower to the top of one of its leaves, it found it difficult to enter, however, after a drifting to the underside of the leaf (stomata) it was diffused and entered a palaside cell where it was then made into a glucose, starch this process is called photosynthesis. In this process, energy from the sun is being used to change it along with water drown up from the roots, into a simple sugar molecule (C6 H2 O6). Sugars are sometimes joined together to form large starch molecules. Both sugars and starches are known as carbohydrates. Oxygen gas is also formed and released into the atmosphere. One hundred and twenty five years ago, a dinosaur was walking through Wye Valley. The surrounding area was full of carbon atoms from the atmosphere, vegetation and exhaled air. The dinosaur was searching for food. As he walked around the
Determine the penetrating power and the range in air of the three radioactive emissions (Plutonium 239 for alpha, Strontium 90 for beta and Cobalt 60 for gamma).
Aim To determine the penetrating power and the range in air of the three radioactive emissions (Plutonium 239 for alpha, Strontium 90 for beta and Cobalt 60 for gamma). Method 1 The apparatus were set up as in the diagram below to measure the range in air up to 50 cm for each source. Before the experiment took place the background radiation was measured as 80 counts in 5 minutes therefore 16 counts per minute. Experimental precautions were: The radioactive source is aligned with a ruler to the GM tube as accurately as possible so that the maximum radiation is measured A set square was used to measure the exact point at which the source and tube were placed The counter was reset each time so the counter read zero so this would reduce zero error in the experiment and the hold button was pressed to freeze the measurement Thirty seconds were left between the start of the count and the recording so the reading would be less instantaneous and more reliable Everything was kept constant for all three experiments and the counts were recorded at regular intervals of 5 cm. Safety precautions included removing the sources from a secure wooden box using thongs and tweezers and placed in plasticene, the set square was held using thongs and all those carrying out the experiment stood behind the source to minimise any direct radiation exposure. Method 2 The equipment was set up
What is the best way to keep hot water hot for the longest period of time
Introduction In this practical experiment, I am going to find out what is the best way to keep hot water hot for the longest period of time. The way that this can be achieved is by preventing, Radiation, Convection and Conduction. Planning I am going to apply my background knowledge to the experiment so that it is easier to choose which items I am going to use in the experiment. Here is my background knowledge. Background knowledge I already know that heat can be lost by conduction, convection and radiation. Therefore it would be in great interest to look into these in depth as then I can see how I can prevent these from occurring. The first way I am going to cover is conduction Conduction- Conduction is what occurs in many solids. The way it is mainly passed is through the solids' vibrations. This is how the solid will look as the vibrations are passed through it. Most non-metals are not good conductors and are good insulators as they do not vibrate as much so therefore the process of conduction is very slow. Convection- The convection of heat occurs in liquids and heat only. It is a much more effective process then conduction so I am going to concentrate on stopping convection more then stopping conduction. Convection is when heat from a hot region takes the heat and moves to a cooler region. Here is a picture of what happens in the convection
Physics Argument - Is Sunbathing Good For You?
Is Sunbathing Good for You? The ultraviolet radiation (UV) in sunlight can cause skin cancer. there are many factors that can effect the risk involved when you sunbathe. Your skin tone can effect the damage caused by UV radiation because the brown pigment in skin, menalin, provides some protection. The darker your skin the more protected you are from the damaging effects of sunlight. If you have particularly fair skin, you should take extra care when sunbathing; use a suncream with a high SPF and don't stay out in the sun for prolonged lenghts of time. The amount of time you can spend in the sun varies from person to person but if you know you are proned to burning or if you have a family history of skin cancer you, too, should take extra precautions. People who have had excessive exposure to UV radiation from the sun without protection are at a greater risk from skin cancer as this is the most common cause of skin cancer. Again, you could avoid this by using suncream and not staying out for too long. Males are 2-3 times more likely than females to have basal cell and squamous cell cancers. All children should wear suncream because they have more sensitive and reactive skin than adults. Playing in the sand and swimming can remove many protection screens so it should be reapplied as often as possible, children are recomended to wear a sunscreen with an SPF of 30 or above.
Radioactivity revision notes
Radioactivity Some nuclei are more unstable than others. However, they wish to become stable and do this by radioactive emissions. We can also cause or stimulate nuclei to decay by causing it to absorb a neutron. This in turn makes it unstable causing it to decay. We detect radioactive emission using a Geiger-Muller tube connected to a counter. The unit of radioactivity is the Becquerel (Bq); one Becquerel is one count per second. Radioactivity is around us all the time from a variety of sources. This is called background radiation. Radon gas 50% Ground and buildings 4% Medical 4% Food and drink 1.5% Comic rays 0% Nuclear power 0.3% Other 0.2% When measuring the radioactivity of any sample, we must always subtract a previously measured reading of background radiation from all measurements. Types of Radiation There are 3 types of radioactive emission: ) Alpha (?) - this has a helium nucleus and consists of 2 protons and 2 neutrons. It is the most massive but also the most ionizing type and can travel only 1-2cms in air before they are stopped. It is stopped by thin paper or skin. 2) Beta (?) - this is an electron emitted from the nucleus when a neutron changes into a proton. It is smaller and less ionizing and can travel metres through the air before being stopped. It requires a more dense material such as aluminium to stop it. 3) Gamma - (?? - this is an
How safe are Mobile phones?
Introduction Mobile phones are becoming an essential business tool, a popular means of communication. In my report, I will be talking to you about mobile phone safety, then I will come to a conclusion based on my evidences and statistics. Disadvantages Mobile phones have numerous advantages but they also bring some disadvantages. * Effects on health The radiations of mobile phones are causing serious health hazards to the users. The mobile phone users are more prone to ear defects, headaches and blurring of vision1. This source is reliable because it is from the BBC website and the BBC website is not biased. It is valid because the article was published in 2005. This was a Swedish study carried out in 2002. Altogether 1249 people were surveyed, so it is reliable. SAR values are an indication of how much heat is absorbed into the head. The more the value, the more heat absorbed. This graph shows the top 10 SAR values in Europe for mobile phones2: Manufacturer Model SAR Rating W/Kg Sony Ericsson T650 .80 Sony Ericsson W880i .45 Nokia E51 .40 Sony Ericsson W950i .35 Sony Ericsson Z610i .32 Sony Ericsson K810i .31 Sony Ericsson W610i .31 Sony Ericsson W660i .27 Sony Ericsson K550i .25 LG & Nokia KU250 + N5700 .24 This graph shows that the phone with the highest SAR value in Europe is the Sony Ericsson T650. The information collected has
Rutherford's Alpha Particle Scattering Experiment:The discovery of the Nucleus...
Rutherford's Alpha Particle Scattering Experiment: The discovery of the Nucleus... Rutherford was the world leader in alpha-particle physics. In 1906, at McGill, he had been the first to detect slight deflections of alphas on passage through matter. In 1907, he became a professor at the University of Manchester, where he worked with Hans Geiger. This was just a year after Rutherford's old boss, J. J. Thomson, had written a paper on his plum pudding atomic model suggesting that the number of electrons in an atom was about the same as the atomic number. (Not long before, people had speculated that atoms might contain thousands of electrons. They were assuming that the electrons contributed a good fraction of the atom's mass.) Rutherford's alpha scattering experiments were the first experiments in which individual particles were systematically scattered and detected. This is now the standard operating procedure of particle physics. Rutherford's partner in the initial phase of this work was Hans Geiger, who later developed the Geiger counter to detect and count fast particles. The experiment was conducted, as is shown below. Alpha particles were fired from a source (from within a lead "shield") at a sheet of thin gold foil (which had been beaten to about 400 atoms thick. A fluorescent screen was placed behind / around the gold foil. Every time an Alpha particle hit the screen
Ionisation smoke alarms use an ionisation chamber and a source of ionising radiation to detect smoke.
Smoke Alarms What Is It? A smoke alarm is a device that can detect smoke; alternatively it can also be called fire alarm systems or household detectors. The smoke alarm was created to detect fires and would consequently give a warning in the form of a signal or an alarm. Smoke alarms are fitted to the ceiling and are usually a very small disk shape size. There are two main types of smoke alarms. The first one and probably the more commercial and cheaper one is the physical process alarm (Ionisation). These are usually powered by a single disposable battery. The other main type of smoke alarm is photoelectric, which basically works by optical detection.[1] This report is on Ionisation smoke alarms. How Do They Work? Ionisation smoke alarms use an ionisation chamber and a source of ionising radiation to detect smoke. These are the more inexpensive ones however; one major disadvantage of ionisation detectors is that they are sensitive to very small particles of smoke. An ion is an atom with a positive or negative charge.[2] To ionise means to remove an electron from an atom and purposely create positive and negative ions. Inside the ionisation chamber is a tiny amount of americium 241.[3] The reason why americium is often used instead of other radioactive elements is that americium 241 has a very long half life of 432 years. It is a very good source of alpha particles. The
What is Spectroscopy?
What is Spectroscopy? Spectroscopy is the study of energy levels in atoms or molecules, using absorbed or emitted electromagnetic radiation. There are many categories of spectroscopy eg. Atomic and infrared spectroscopy, which have numerous uses and are essential in the world of science. When investigating spectroscopy four parameters have to be considered; spectral range, spectral bandwidth, spectral sampling and signal-to-noise ratio, as they describe the capability of a spectrometer. In the world of spectroscopy there are many employment and educational opportunities as the interest in spectroscopy and related products is increasing. However Spectroscopy is not a recent development, as it has been utilized for many years since Isaac Newton made the first advances in 1666. Spectroscopy is the study of light as a function of wavelength that has been emitted, reflected or scattered from a solid, liquid, or gas. Fundamentals of Spectroscopy Spectroscopy is the distribution of electromagnetic energy as a function of wavelength. Spectrum is basically white light dispersed by a prism to produce a rainbow of colours; the rainbow is the spectrum of sunlight refracted through raindrops. All objects with temperatures above absolute zero emit electromagnetic radiation by virtue of their warmth alone; this radiation is emitted at increasingly shorter wavelengths as temperature is
AIM OF EXPERIMENT: TO DETERMINE THE RATE OF REACTION OF HALOGENOALKANES
AIM OF EXPERIMENT: TO DETERMINE THE RATE OF REACTION OF HALOGENOALKANES EQUIPMENTS REQUIRED * Eye protection * Marking pens or labels * A test tube rack and 6 test tubes * Beaker ( 250cm3) * Bunsen burner, tripod stand * Measuring cylinder (10cm3) * Thermometer ( 0oC-100oC) * Stop clock * Source of laser light. * 1-bromobutane* * 1-chlorobutane # * 1-iodobutane* * Silver nitrate solution (0.1mol dm-3) * Ethanol# * Dropping pipettes : 1 for each bottle * Source of hot water * Harmful. Eye protection must be worn # Highly inflammable. Keep tubes and bottles away from naked flame. INTRODUCTION A halogenoalkane is a compound which has a carbon (C) - halogen(X) bond in its carbon chain. The C?+? X?-bond is polarised due to the difference in electro negativity between the carbon atom and the halogen atom. This induces the slightly positive charge on the carbon atom and the slightly negative charge on the halogen atom. The slightly positive charge on the carbon atom makes it open to nucleophilic attack. This results in the displacement of the halide ion. This experiment will compare the rate of hydrolysis of 1-chlorobutane, 1-bromobutane and 1-iodobutane where H2O acts as a nucleophile. METHOD: ) Fill a two-thirds of a beaker with water and insert a thermometer into the beaker 2) Heat water in a beaker till it reaches about 50oC 3) Put 1 cm3 of 0.1mol
