• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Ultraviolet radiation and skin cancer

Extracts from this document...

Introduction

ULTRAVIOLET RADIATION AND SKIN CANCER Skin cancer is the most common malignancy in humans and accounts for one third of newly diagnosed cancers. It is estimated that skin cancer will be diagnosed in around 1 in 5 Americans during their lifetime and more than 1 million cases are diagnosed each year [1]. Ultraviolet light from the Sun is the main cause of skin cancer and plays a major role in the 2-3 million non-melanoma skin cancers and 132,000 malignant melanomas that occur annually. The incidences of skin cancer are becoming more and more common, causing global concern. There could be many reasons for this. For example, people are living longer and so their lifetime sun exposure is increased. They also have more money to spend on outdoor activities and holidays in sunny climates. Many still feel that suntans are healthy and attractive and therefore deliberately expose themselves to the sun and consequently to UV radiation [2]. Due to the causal link between UV light and skin cancer, its prevention and protection against this type of radiation has been at the forefront of a lot of research done by companies such as the World Health Organisation. They have set up a scheme called INTERSUN, a 'global UV project'. This project promotes research activities that aim to fill in gaps in knowledge and quantifies the health risks of UV exposure [3]. ...read more.

Middle

of some minimum size. He proposed that the energy, E, of a single quantum equals a constant times its frequency. That is: E = hf. h is the Planck constant: h = 6.63 x 10-34 and energy is always emitted or absorbed in whole-number multiples of hf. The photoelectric effect refers to the phenomenon in which electrons are emitted from the surface of a substance when light strikes it. We can attempt to explain the photoelectric effect using something called the Bohr Model. In this model an electron in an atom, in a given orbit around a nucleus, can only absorb energy in multiples of a certain definite amount. These multiples are referred to as the different energy levels of the atom. In the same way, the only way the electron can lose energy is by dropping from one energy level to another one. When this happens, the atom emits a photon of radiation corresponding to the difference in energy levels. When all energy levels are filled electrons in higher levels cannot move to lower levels and therefore cannot lose energy. At this point the atom energetically stable and is said to be in its ground state. Atoms can absorb energy from an outside source (such as the Sun), causing one or more of the electrons within the atom to move to higher energy levels. ...read more.

Conclusion

hf is a packet or quanta of energy. Planck formed this equation by looking at how small electric oscillators radiated and absorbed radiation where their collective distribution of energy of the radiation was similar to that of the blackbody spectrum. He found that oscillators with a particular amount of energy only emitted particular frequencies of radiation. At high frequencies (short wavelength radiation) the energy needed to emit one quantum of radiation was very large, and only a few of these oscillators had this much energy (in accordance with statistics) therefore only a few of these high-energy quanta are emitted. At very low frequencies (long wavelength radiation) a lot of low energy quanta were emitted, but as they all have so little energy their sum still wasn't significantly large. It was only in the central range of frequencies that there are enough oscillators to emit a lot of radiation. These electric oscillators are similar to vibrating atoms in the Sun. Planck's findings did provide an explanation for the peak in the blackbody curve and why the Sun emits radiation in the way that it does [11]. Below is a graph showing the curves of three different blackbodies. It was made using Wein's law. We can see from this graph that as the temperature of the blackbody increases the magnitude of the peak increases and shifts towards the shorter wavelengths. This fact is significant for future generations as the Sun's temperature is increasing and as it does, more and more ultraviolet radiation will be emitted. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Radioactivity section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Radioactivity essays

  1. Peer reviewed

    Ionisation smoke alarms use an ionisation chamber and a source of ionising radiation to ...

    3 star(s)

    Gamma rays can be used for sterilizing medical equipment. They can be used to see inside patients and they can be used as a tracer. In some cases gamma can also be used to kill cancerous cells.[16] Why Is It Safe? The risk of harm from exposure of radiation from a smoke alarm is considered to be small.

  2. Peer reviewed

    Rabbit Proof Fence Essay - review

    When the Europeans thought that the aboriginals would just die out on there own, they were wrong. There are still Australian aboriginals around today. The policy encouraged a sense of superiority by the whites and a sense of inferiority by the aborigines.

  1. Mutagenesis: The Effect of Radiation on Radish Seeds.

    Figure 2. Effect of gamma radiation on plant leaf length. Plant Leaf Length Data At Various Radiation Doses Amount Avg. & Std. Dev. (mm) P Value Effect Control (0 Rads) 6.778 � 4.764 --- --- 50,000 Rads 15.44 � 15.02 0.4433 N 150,000 Rads 3.778 � 7.513 0.1425 N 500,000

  2. Are mobile phones harmful to our health

    Retired Swedish electrical engineer Orjan Hallberg, who has written several papers on mobile phones, said: "Electromagnetic radiation is affecting the immune system and this makes it easier for cancer cells to continue to develop. "I think it will become really serious as more of us are already finding relatives and friends who have been struck by brain cancer.

  1. Thermionic emission and Radiation and half-lives.

    Scientists now have the technology to create radioactive forms of common and stable elements, these are called isotopes. Each isotope has a fixed rate of decay which can be characterized by its half-life, a half life is the amount of time it takes for half of the radioactive atoms in a sample to decay to stable elements.

  2. Smoke Alarms Assignment In this CDA I will be explaining how smoke alarms work, ...

    This enables the smoke detector to be able to detect smoke while also not causing diseases among human beings who come into close vicinity to it on regular basis. Smoke alarms each contain 30,000 Bq. The radioactivity in ionising detectors is a film coated with Americium 241, a relatively long-lived

  1. Can mobile phones cause cancer

    Now I'm going to present my questionnaire. Are you male or Female? Male Female Have you or anybody you know suffered from cancer? Yes No If so, what type of cancer? ......................................................................................................... Would you assume that if you had received cancer, you would die? Yes No Do you agree with the concept of voluntary euthanasia?

  2. REsearch into the dangers of sunbeds.

    This is generally felt to be more hygienic. Most modern tanning beds have not changed much from the previous systems. The lamps technology and electronics have evolved other the years, but the basic ?low pressure? tanning bed has not evolved.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work