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The two raw materials: baking soda and vinegar, used to make hot ice need to be free of impurities. Ensuring this is very difficult, which is why it is better to purchase ready-made sodium acetate. You can purchase it from online stores like eBay, Trade Me, etc. Sodium acetate is also available in warming pads, hand warmers, etc. Just cut open these pads or hand warmers with a knife and empty out the contents. However, sodium acetate obtained from these warming applications will appear like a gel. Nevertheless, it satisfies the purpose. Moreover, purchasing ready-made sodium acetate simplifies and speeds up the entire hot ice making process.

Requirements
•Sodium acetate powder (One cup)
•Water
•Steel saucepan
Preparation Procedure

Step 1
In a steel saucepan, add two cups of water and begin heating it. Now, gradually add a cup of sodium acetate into the water and stir, so that it dissolves. Do not add it all at once. Instead, add it gradually, ensuring all the crystals are getting dissolved.

Step 2
The solution should not be brought to a boil, instead must be heated on low heat. Do not overheat the solution, or else the solution will develop a yellowish or brownish tinge on solidifying. This will not look so appealing in a science fair, as it will not resemble ice.

Step 3
Keep stirring the solution, as you add sodium acetate crystals. Now, the key here is getting a supersaturated solution. This is because, if the solution is not supersaturated, when the solution is placed in the refrigerator, it will crystallize, thereby defeating the whole aim of the experiment.

Step 4
Since we are looking for a supersaturated solution, we need to make sure no more sodium acetate crystals dissolve into the water. You will know the solution is supersaturated, when some crystals remain at the bottom of the beaker or saucepan, even after stirring for quite a while. This indicates your supersaturated solution of sodium acetate is ready.

Step 5
You can also do it the other way round, wherein, you can first add sodium acetate into the beaker and then add water gradually. However, be careful not to add too much water. read more »

Argument 1: Economic progress is said to improve our standard of living. On the other hand, this very progress can lead to degradation of the environment. The differences between these conflicting views are discussed below.

The economy vs. environment debate started few decades ago and it has become quite a popular one in today’s world where economic growth is associated with environmental degradation. Points mentioned in the following and subsequent paragraphs should help us find some useful information on this topic.

There is a common belief in our society that preserving the environment is somehow linked with compromising on economic terms. This very belief has fueled the economy vs. environment debate. However, the truth is exactly opposite to this perception of ours. In reality, there is enough that the planet earth can provide us to satisfy our needs. Our economy can prosper and sustain in the long run without putting undue stress on the natural resources. It is the greed to possess and enjoy as many luxuries as possible that has led to the state in which we find ourselves, today. The use of green technologies and renewable sources of energy should solve the energy crisis to a great extent without putting any burden on the existing natural resources. It means the economic growth of the country/region in question doesn’t get hampered owing to environmental concerns. There is another misconception that conservation efforts require you to spend a lot of money to be successful. In reality, it is the awareness and a bit of effort on our part that can save many trees and animals on this planet. Even a simple act of planting and nurturing a sapling holds great importance in the process of environmental conservation. Such kind of efforts need to be concentrated in order to bring about a bigger and long-lasting change. The following paragraphs throw light on different aspects of the economy vs. environment debate through explanations about various subjects. Let us start with the topic of environmental ethics. Before getting into the details of environmental ethics, one must be aware about globalization and its impact on the environment to get a better idea of the subject of economy vs. environment.

Argument 2: Industrialists believe that economic progress gets hampered by putting restrictions on the way their operations are conducted. Environmentalists, on the other hand, demand for impractical rules and regulations to be put on working of industries. The details on these arguments can be found below. read more »

Despite numerous advantages of forensic science, there are some ethical, legal, and knowledge constraints involved in forensic analysis.

☛ DNA analysis of a person is believed to be against human ethics, as it reveals private information about an individual.
☛ Equipment used in forensic science is expensive.
☛ Scientific analysis in forensic science consumes lot of time because of which the verdict is delayed.
☛ Forensic science requires precise and accurate analysis. Even if a minor error occurs in the analysis, it may result in the wrong figure.
☛ The evidence cannot be accessible at all times.
☛ Evidence is prone to manipulation, which may end up in an unrighteous verdict.
☛ Interpretation of the analysis differs from one forensic scientist to another.
☛ Forensic analysis can be prevented by strong influences (political or financial factors).
☛ There is no particular standard to verify the result of the experiment. It requires wide knowledge and intensive study.
☛ Innovation is hindered as the approach is mostly the same.
☛ Misconceptions and ignorance can mislead the experimental analysis.
☛ Maintaining privacy and secrecy of the information gathered through forensic analysis is quite difficult.

Forensic science analysis is not an easy task to accomplish. It involves a lot of hindrances and challenges. Forensic science is not a single independent subject. It is a combination of various subjects like engineering, pathology, linguistics, forensic seismology, forensic toxicology, forensic anthropology, microchemistry, criminalistics etc. The law enforcement agencies are highly dependent upon forensic science to establish justice.

A peak voltage of 50kV (50,000 volts) is generated inside the gun, however, it delivers lesser power because of some resistance that is offered by the target medium. When a circuit that produces electrical signals (Taser waves or T-waves) is established, a series of pulses 100 micro-seconds wide are generated inside the gun. The gun generates 19 such pulses per second. By making a simple calculation using these parameters, we can get the average current emitted from the Taser gun, which is 1.9 milliamperes.

The electrical signals from a Taser gun affect the human body by exploiting its skeletal and heart muscles.

Heart Muscles: The heart muscles are made up of interconnected fibers, which are made up of cells. The cell-to-cell resistance is very low and any electrical impulse that strikes a cell can quickly pass to the other cell in very little time. The conduction tissue of the heart is designed to enable smooth functioning of the four chambers of the heart. When a jolt of current at the right frequency hits the heart, a situation known as ventricular fibrillation (uncoordinated contraction of the ventricles of the heart) is created in the heart. Tasers cause this situation inside the human heart.

Skeletal Muscles: When a human brain orders a muscle tissue to contract, an electrical impulse travels down through the motor nerve and terminates at the middle of a muscle fiber. Here, the Taser pulses exploit the skeletal muscle fibers by directly jolting the motor nerves with electricity. The electrical signal from the Taser is converted into acetylcholine and binds with gated-ion channels when it comes in contact with the muscle fibers. The receptors (gated-ion channels) open up, allowing the sodium ions from the surrounding salty fluids to flow into the muscle. We know that movement of electric ions produce voltage. Likewise, this movement of sodium ions into the cells of the muscles, increases the inner cell voltage and also triggers the nearby ion-channels. Thus, a wave of voltage runs between the ends of the muscles which make them contract.

The pulses that are emitted from the Taser gun are designed considering the chronaxie (minimum time required to cause stimulation of a muscle fiber or nerve cell) of the heart and the skeletal muscles. The electric current (1.9 mA) from the Taser gun is far below the danger zone of a healthy human body. read more »

Mobile Phone as a Credit Card?
Radio Frequency Identification (RFID) is a very fast growing technology, which uses radio waves to transmit information from a device or a tag. One of the important applications of RFID is near-field communication (NFC) which allows money transactions, and information exchange between devices which have NFC chips embedded in them. A smart phone could be used as a credit card and an ID card, if it has the NFC radio frequency chip, enabled with NFC standards.

4G Mobile Technology
4G (fourth generation) technology is an initiative that aims to move beyond the limitations and problems in the present 3G technology. Some of the enhancement features projected in 4G technology are:
•Higher data rate
•Broader bandwidth
•Smoother and quicker handoff
•Seamless service
•High quality voice communication
•high-definition video
3G technology mobile phones can deliver a data rate of 384Kbps to 2Mbps. 4G aims to reach a limit of 100Mbps for mobile phone users and 1Gbps for stationary users. 4G implementation is quite expensive and is not available in all mobile phones now. It is expected that soon 4G will spread and will be widely used by all mobile phone users.

Mobile Commerce
Mobile phones enabled with Internet services are used by business analysts for mobile commerce. Mobile commerce is defined as “Mobile commerce is any transaction, involving the transfer of ownership or rights to use goods and services, which is initiated and/or completed by using mobile access to computer-mediated networks with the help of an electronic device.” Business-to-business (B2B) and business-to-customer (B2C) are the two important applications of mobile commerce. Mobile commerce technology started to grow rapidly from the year 2000 onwards. Some of the mobile commerce services are mobile banking, mobile marketing and advertising, mobile brokerage, auctions, etc. read more »