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Write a note on the science behind the following ,advantages and disadvantages. Add some websites , videos atleast 5                                               .1.Smoke detectors                2.Markers to track biological processes in plants to better understand their physiology  3.Food irradiation (to preserve canned foods) 4.Archaeological dating of artefacts                     5.Forensic analysis of crime scene or accident remains    6.Medical applications (For example- nuclear medicine in hospitals to determine bone health, radiation therapy for cancer patients, chemotherapy for cancer patients)7.Sterilization of sensitive instruments.

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Write a note on the science behind the following ,advantages and disadvantages. Add some websites , videos atleast 5                                               .1.Smoke detectors                2.Markers to track biological processes in plants to better understand their physiology  3.Food irradiation (to preserve canned foods) 4.Archaeological dating of artefacts                     5.Forensic analysis of crime scene or accident remains    6.Medical applications (For example- nuclear medicine in hospitals to determine bone health, radiation therapy for cancer patients, chemotherapy for cancer patients)7.Sterilization of sensitive instruments.

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https://www.insidescience.org/video/smoke-alarm-distinguishes-actual-fire-burning-food

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A smoke detector can be used  in an industrial setting, usually their hooked up to a larger fire alarm system or as an independent device in your homes. There are two types of smoke detectors : the photoelectric detector, and the ionization detector.

Inside this circular device is an enclosed space where, on one end, a beam of infrared light (or light from a LED) travels unblocked toward the other end of the enclosure where a photodiode (a tiny, tubular component that turns light into electric current) is mounted. The light beam does not hit the photodiode; it is directed slightly away from it. However, when smoke is present in the area, it enters the smoke detector and gets into the space where the light beam and light detector (the photodiode) are mounted. Smoke particles scatter the previously straight light beam and cause some of it to hit the photodiode. The photodiode will then convert the light into an electrical pulse that sounds the alarm. This type of smoke detector is effective in detecting smoke coming from smouldering fires, but some reports show that it may need substantial amounts of smoke particles to disturb the light beam before the alarm mechanism is activated.

https://www.livescience.com/33788-smoke-detectors-work-llmmp.html

links:
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/radiation/radioisotopesrev3.shtml

http://www.gcsescience.com/prad26-radioactive-smoke-detector.htm

http://www.todayifoundout.com/index.php/2012/04/how-a-smoke-alarm-works/

video:
https://www.insidescience.org/video/smoke-alarm-distinguishes-actual-fire-burning-food

https://www.youtube.com/watch?v=pcn7MDpoZrY

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tracers (nuclear medicine):
Radioactive tracers are used to investigate a patient's body without the need for surgery. Gamma emitters and sometimes beta emitters are used. This is because gamma rays and beta particles can pass through skin, whereas alpha particles cannot.

A small amount of radioactive material is put into the patient's body. The radiographer puts a detector around the body to detect any gamma rays or beta particles that pass out of the patient's body.

treating cancer (MRI):

Gamma rays damage cells whether they are normal or cancerous, so gamma rays must be focused on the tumour. One way of doing this is to use a wide beam of gamma rays, but to rotate the beam around the patient, keeping the tumour at the centre. This concentrates the gamma rays on the cells that need to be killed.

cancer therapy (cobalt)

Radiation therapy works by damaging the DNA (genetic material) of cells. A radiation beam of photons, electrons, protons, or neutrons can be used to disrupt the growth of tumour cells by directly or indirectly ionizing the DNA (deoxyribonucleic acid). The cell with damaged DNA dies during cell division.

http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/radiation/treatmentrev4.shtml

https://www.britannica.com/story/how-radioactive-isotopes-are-used-in-medicine

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disadvantages

1. The major demerit of using radioisotopes in nuclear medicine is that it has a negative impact on health. Tissues are damaged, leading to skin burns, nausea,diseases such as leukemia and lung cancer, this eventually leads to death.

2. Radioisotopes are very expensive and not every hospital can pay the price for consuming them. They are also inevitably hard to store since they continuously omit radiation

3. Theres more work that has to go into using radioisotopes, as radioactive wastes from using radioisotopes can't be dumped into any place, they need disposals that are not going to have an effect on omitting radiation to people or to the ozone layer causing a green house effect.

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Advantages
It helps in determining the cause of death by examining the postmortem changes, blunt injuries, burns and scalds.
The alcohol content in a human can be determined by analyzing the blood and other body fluids like saliva and urine.

https://www.google.com.sg/search?q=Forensic+analysis+of+crime+advantages&oq=Forensic+analysis+of+crime+advantages&aqs=chrome..69i57.5230j0j7&sourceid=chrome&ie=UTF-8

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Working Conditions, Occupational Hazards,Emotional and Physical Effects,Public Image.
https://careertrend.com/disadvantages-forensic-scientists-25978.html

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Scientific method:
http://www.sfu.museum/forensics/eng/pg_media-media_pg/isotopes/

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less food spoilage.

extended shelf life of some products.

less need for pesticides.

lower risk of importing or exporting insect pests hidden inside food products.

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A photoelectric smoke alarm employs a light beam to detect smoke particles in the air. When particles are present, they block the beam and the alarm sounds. However, a false alarm can occur by issues that have nothing to do with smoke or fire. A alarm may go off by e.g. Humidity, dust and insects, strong chemical odours, your detector’s location, and power issues.

The alarm may detect the dust or humidity as smoke particles, causing the alarm to go off.

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Addvantages

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The equipment is placed in an air tight bag which is placed in a field of gamma radiation. Gamma radiation has enough energy to ionize atoms and molecules. After the cells are ionized they make free radicals. These free radicals damage the nucleus of the cell so that it cannot function properly. After this the cells/ molecules will die, which causes the equipment to be sterile.

http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/radiation/treatmentrev2.shtml

https://prezi.com/uyfeeqq59acl/radioactivity-used-to-sterilize-medical-equipment/

https://hps.org/publicinformation/ate/q4004.html

https://www.youtube.com/watch?v=of7-jrmP_Ok

https://www.youtube.com/watch?v=of7-jrmP_Ok

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A Smoke detector that is part of a fully integrated Smart Home is always safer, smarter and more efficient than a standalone fire/smoke detector, particularly when it comes to taking action in an emergency.

Video:
https://www.youtube.com/watch?v=DHPXSYZRjAg

Website: http://www.haramiselectric.com/blog/advantagesdisadvantages-smart-smoke-detectors/

https://servicefireequip.com/the-benefits-of-smoke-detectors-for-homes/

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advantages:

Nuclear medicine uses radiation to provide diagnostic information about the functioning of a person's specific organs, or to treat them. Diagnostic procedures using radioisotopes are now routine.

Radiotherapy can be used to treat some medical conditions, especially cancer, using radiation to weaken or destroy particular targeted cells.

Over 40 million nuclear medicine procedures are performed each year, and demand for radioisotopes is increasing at up to 5% annually.

Sterilization of medical equipment is also an important use of radioisotopes.

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Isotopic labelling is a method that tracks the passage of an isotope or a cell

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Disadvantages: The

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Radioactive or radiometric dating means determining the age of certain archaeological artifacts (fossils, minerals) with the help of radioactive isotopes.
Isotopes are found in most substances. Some types of isotopes don't change over time, and are classified as stable. The unstable ones (radioactive isotopes) break down by radioactive decay to form different isotopes.
The nucleus of radioactive isotopes give off  radioactive particles, changing into another isotope at a constant rate. The original isotope is known as the "parent" element, and it decays into a stable "daughter" element at a constant rate.
The rate of decay is how much of the parent atoms decay in a set period of time, which for geological purposes is usually a year. Another way of expressing this is by finding the time it takes for half of the parent atom to decay, which is known as the half-time.

Many different radioactive isotopes and techniques are used for dating. All rely on the fact that certain elements (particularly uranium and potassium) contain a number of different isotopes whose half-life is exactly known and therefore the relative concentrations of these isotopes within a rock or mineral can measure the age. For an element to be useful for geochronology (measuring geological time), the isotope must be reasonably abundant and produce daughter isotopes at a good rate.

Either a whole rock or a single mineral grain can be dated. Some techniques place the sample in a nuclear reactor first to excite the isotopes present, then measure these isotopes using a mass spectrometer (such as in the argon-argon scheme). Others place mineral grains under a special microscope, firing a laser beam at the grains which ionises the mineral and releases the isotopes. The isotopes are then measured within the same machine by an attached mass spectrometer (an example of this is SIMS analysis).

There are a few different types of radioactive dating such as:
* radiocarbon dating - this is the most common technique
*  Rubidium-Strontium dating
* Potassium-Argon dating
* Samarium-Neodymium

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Food irradiation is the application of ionizing radiation to food this makes food more durable and safer to eat by eliminating microorganisms and insects from inside or outside of the product, it is the same concept of pasteurizing milk and canning fruits and vegetables it makes it safer to consume the food. The FDA (Food and Drug Administration) is the administration responsible of regulating the radiation used on foods and will only do so if determined that irradiating the food is safe.

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- high cost
- Higher temperatures required -> harmful to some materials
- With the use of gamma radiation, Limited applicability to kits.
- slow and uneven penetration -> longer time required.

https://www.slideshare.net/MaziyatulkarimahMasrur/sterilization-of-medical-instruments-radiation

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https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/production-and-inspection/irradiation-and-food-safety/irradiation-food-safety-faq

https://www.betterhealth.vic.gov.au/health/healthyliving/food-irradiation

https://www.fda.gov/food/resourcesforyou/consumers/ucm261680.htm

http://www.foodstandards.gov.au/consumer/foodtech/irradiation/Pages/default.aspx

https://connectusfund.org/7-advantages-and-disadvantages-of-food-irradiation

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1. Expensive, because you have to determine the isotope of very trace quantities of radioelements, and not just the concentration of the element in a mass spectrometer
2. Requires highly skilled specialists
3. Will not work for fossils or sedimentary rocks
4. Possible sources of error such as a contamination of a sample
5. Possible errors in determining isochron
6. Not all samples are suitable for radiometric dating
7. The isotope must be abundant and change into the next isotope at a good rate

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- Effective operation at low temperatures
- Fast and efficient
- With the use of gamma radiation, sterilisation can be done on equipments with smaller, more complicated parts which cannot be disassembled
- No pollution of toxic fumes are distributed
- Non corrosive, no rust

https://study.com/academy/lesson/advantages-disadvantages-of-dry-heat-sterilization.html

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List of Disadvantages of Food Irradiation1. No PromisesOne of the problems with food irradiation is that there is no definitive way of killing all of the organisms that can come into contact with our foods. Some organisms are in fact resistant to the mild radiation that is utilized.2. AnimalsStudies going back several decades come to the same conclusion over and over again. Irradiated foods can cause health problems with a variety of animals. Rare cancers, chromosome abnormalities, and even premature deaths can occur.3. Colors and TexturesBoth vitamins and minerals are at risk through irradiation. Worse yet, the textures and flavors can also be altered through this process. For many people, these changes are unpleasant. The smell of beef after irradiation is one example.

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List of Disadvantages of Food Irradiation1. No PromisesOne of the problems with food irradiation is that there is no definitive way of killing all of the organisms that can come into contact with our foods. Some organisms are in fact resistant to the mild radiation that is utilized.2. AnimalsStudies going back several decades come to the same conclusion over and over again. Irradiated foods can cause health problems with a variety of animals. Rare cancers, chromosome abnormalities, and even premature deaths can occur.3. Colors and TexturesBoth vitamins and minerals are at risk through irradiation. Worse yet, the textures and flavors can also be altered through this process. For many people, these changes are unpleasant. The smell of beef after irradiation is one example.

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Advantages:
- Identification
- Normalization (easier to compare between experiments at different times)
- Finding Photosynthesis rate

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1. It is a reliable process
2. A vast variety of radioisotopes can be used, so almost any age of material can be dated
3. Archaeological dating is very accurate, usually to within 1%

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https://www.youtube.com/watch?v=pe6AKh_tLys

https://www.youtube.com/watch?v=_9vwS3_s1b4

https://www.youtube.com/watch?v=2MJc_WNl7ME

https://www.youtube.com/watch?v=087JTrlRUfk

https://www.youtube.com/watch?v=ETx-cZ01kXE

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https://www.youtube.com/watch?v=mk9bUAD4dS8

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https://www.youtube.com/watch?v=phZeE7Att_s

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https://australianmuseum.net.au/radioactive-dating
https://www.crowcanyon.org/index.php/radiocarbondating