The Freezing Point Depression

In my Current Topics class recently, we have been preparing a demonstration of a scientific topic and a lab activity that can go along with it. My group’s topic is the freezing point depression. It may not sound that complicated, and it is actually is rather simple, although it took much discussion, arguing, and questioning to figure out exactly how the freezing point depression works. This has been a topic of interest for my group over the past couple of weeks and turned out to be quite fascinating.

Depressing the freezing point or melting point of a substance, since the temperature below which a substance freezes and above which a substance melts is the same, simply refers to the process of lowering the temperature at which a solid can melt into a liquid. This can be done with the addition of salt. We found a fun experiment to do, which was the “Ice Cream Lab”, which was supposed to demonstrate the freezing point depression. Although it took us a while to figure out how it was being exemplified in the experiment, eventually we came to a conclusion. Basically, the ice cream ingredients are put in a bag that is placed inside a larger bag containing a salt and ice mixture. The salt allows the ice to remain at its normal temperature (below 0°C), but melt into its liquid form. This salt and ice brine that surrounds the ice cream ingredients allows the cream to freeze properly and uniformly, therefore, helping in the process of making homemade ice cream.

Even though we liked this lab activity, we thought that it was very important to see if and how this principle could relate to the real world and be applied to our daily lives. We researched and discovered that salt is put on roads in the winter season for the same purpose, and based on the same principle. Since Winnipeg is very cold, snowy, and icy, for at least 4 months of the year, the use of salt on the roads in very significant to daily life in the city. When the salt is put on the ice in winter, it lowers the melting point of the ice, so that the ice is able to melt into liquid water and run off the roads. Because the roads in Winnipeg get so icy and slippery in the winter and create dangerous driving conditions, the principle of the freezing point depression is essential for keeping the people out of hazardous situations.

I think asking and being critical of why something is happening is important to growing and understanding how the world works. We decided that in order to continue with this lab, we needed to understand why salt was able to depress the freezing point of ice. The answer has to do with the structure of water at a molecular level. Water is made up of H₂O molecules, and the positively charged hydrogen atoms of the water molecules are attracted to the negatively charged oxygen atoms of other water molecules, in a process called hydrogen bonding. In liquid water, because there is more heat energy, the molecules are able to move faster and flow past each other more easily. Similarly, as the temperature of water decreases, the rate of movement of the H₂O molecules is slowed down. Because of this reduction in speed of the moving molecules, the positive hydrogen atoms and negative oxygen atoms bond more firmly to one another and create a crystallized structure (ice). In simpler words, when salt is added to ice water, the salt particles disrupt the bonding process of the water molecules, allowing the substance to remain in liquid form at a temperature where it would normally be a solid. Because of the addition of salt, the molecules that would normally attract each other and bond firmly together at temperatures below 0°C, are interrupted in the process, decreasing the number of bonds formed and therefore, keeping the liquid from entering into a solid state.

I hope you learned something new about how salt can be used to depress the melting point or freezing point of a substance. If you are looking for an experiment that deals with the freezing point depression, an ice cream lab is a fun way to learn about it! Here is a link to one possible ice cream lab you could perform to become more knowledgeable on the subject and see the freezing point depression in action: http://www2.waterforduhs.k12.wi.us/staffweb/smith/Nancy/chemistry/ice%20cream%20lab.htm

Thank you.

Gender Stereotypes: Effect on Performance?

I read an article that talked about gender stereotyping and the effects that it can have on people, particularly women. It is scientifically proven that women tend not to score as high as men on standard tests in some areas of science or mathematics. Women are also under-represented in science related professions, such as computer science and engineering.

Gender stereotyping, for example, “women are not good in science”, may actually interfere with the ability of women to perform well in science related examinations. For example, women might fear that the gender stereotype could be valid, and that it could possibly apply to them. This kind of negative thinking and the feeling of pressure associated with it could actually cause women to perform worse on science or math related tests.

This study that was described in the article used a psychological intervention called “values affirmation” to try to reduce the achievement gap between men and women in a college physics class. The values affirmation intervention involved having the students write about the importance of personally important values, such as friends and family, for fifteen minutes on two occasions during the course. The idea behind the intervention is that it helps women to more firmly establish a perception of personal integrity and worth, which in turn provides them with greater internal strength to cope effectively, including coping more effectively with the stresses of the course examination. The authors of the study found that the values affirmation intervention significantly improved the course performance of women who expressed a strong belief in the gender stereotype that men will do better in physics than women.

The remarkable thing about the study is that a very brief and pretty simple intervention, which was not even directly related to the course material, was able to a have a significant effect on women’s exam performance and subject mastery in physics. The results of the study also suggest that gender differences in performance in some science areas may reflect students’ expectations rather than their true underlying abilities.

I found this article and study particularly interesting because I am a strong believer in gender equality and breaking down stereotypes and generalizations. I find it fascinating that knowing how people think you will perform on an examination can affect the way your mind works, and the way in which you actually perform. I have always been an advocate for the equality of women and think stereotypes are not only offensive, but usually very inaccurate. Saying and believing things like “women are not as good at science and math” have actually been shown in this study to affect women’s performances, because they do not have full confidence in themselves that they can perform just as well as the men. I strongly believe that stereotyping is not only insulting and untrue for the most part, but that it actually can damage the way a person feels about themselves, and cause them to perform in the way they are expected to perform, rather than to the best of their ability.

The article is called “Reducing the Gender Achievement Gap in College Science: A Classroom Study of Values Affirmation”, and can be found at http://www.sciencemag.org.

Thank you!

Vaccinations: A Matter of Responsibility?

There has been a lot in the news lately about the H1N1 flu vaccines which are now combined with the seasonal flu vaccine.

            According to the Public Health Agency of Canada, any number of people between two and eight thousand die each year in Canada from the seasonal flu virus alone. Last year, less than half of the population was immunized for the seasonal flu virus, and the same goes for the H1N1 virus; but, health officials are hoping that combining the two influenza vaccinations will result in much larger turnout for immunizations this year. Many people may have been scared away from the vaccination due to a rare neurological disorder that some feared was associated with the H1N1 virus vaccine, called Guillian Barré Syndrome, which causes paralysis.

There has also been much talk about a new way for the vaccine to be taken. In Canada, there is now the option of FluMist, which is the same vaccination in the form of a nasal spray. This could be an effective alternative for people who do not want to get a needle, but who want to be vaccinated. FluMist has recently been approved by Health Canada, after being available in the United States for the past seven years. The vaccine is free from preservatives, which eliminates some of the public concern and suspicion, and is also latex free so is not a problem for those with latex allergies. The most common side effect is nasal congestion, but in the United States, FluMist has been shown to be a safe and effective vaccine. This new form of vaccination is available in Canada from anyone between the ages of two and fifty nine years old.

Reading some of this information really made me wonder why so few people get immunized. Is it because of a fear of complications? That is a likely possibility, although the risk of having severe side effects as a result of the vaccination is one in a million, whereas, the risk of getting very sick from the flu itself is over one in five. Is it because so many people do not like needles? This is another popular fear, but should not be a problem anymore with the FluMist option. Is it because people think that they will not get the virus, maybe because they are not in the highest risk group? This brings up another issue which is related to an interesting article I read. It was talking about our responsibilities as humans to get the vaccination, not only for ourselves, but so that others are protected against the influenza. It went on to say that it was selfish to not get vaccinated because of the people that may be negatively affected as a result. I agree that it would be ideal to be immunized and, in doing so, prevent others from being affected by the flu, but I tend to lean towards the importance of personal choice, and think everyone should be able to decide for themselves if they want to get vaccinated.

Here is the article that I read which talked about the importance of getting vaccinated to protect yourself and the people around you: http://www.theglobeandmail.com/news/opinions/refusing-to-get-vaccinated-is-selfish/article1339120/.

What do you think? Is it the responsibility of people to get the vaccine in order to prevent its spreading to others who may be negatively affected as a result? And, is it selfish if you do not get immunized? Thank you!

Is Alcohol Worse Than Crack Cocaine?

I recently read this article in the Winnipeg Free Press entitled “Alcohol worse than crack”. It talked about a new British study that assessed how destructive many substances, including alcohol, cocaine, heroin, crystal meth, LSD, ecstasy, and marijuana were to the individual and to society. Some of the criteria that the rankings of these substances were based on were how addictive it is and the damage it can cause to the human body, as well as many other criteria, including damage to the environment and to families around the world. The study concluded that heroine, crack cocaine, and crystal meth, were the most lethal to individuals, but that alcohol is overall more damaging, as it is much more widely used and causes not only harm to the individual, but to those around them as well. It also showed that drugs like marijuana, ecstasy, and LSD were much less harmful to the society as a whole. The study goes on to conclude that alcohol is connected to higher death rates and crime rates than any other drugs, and is therefore “worse” or more “dangerous” than these other lethal drugs.

I am fully aware of all the damage alcohol can cause to the organs of the human body and the negative social effects it can have; however, I feel as though the article’s title is misleading. Yes, I agree that this particular study showed that OVERALL, alcohol causes a larger number of consequences when looking at the effects on society rather than the individual; but, I think this article may be the cause of even more negative consequences. The majority of people do not think alcohol is all that bad, as it is a widely accepted part of our society. Even in the article it says that “alcohol is too embedded in our culture and it won’t go away”. If one of these people in the majority of the population read this article, that basically – as the title reads – says that it is worse to drink alcohol than to take illegal drugs like crack cocaine and crystal meth, they will be inclined to think that if alcohol is okay, and alcohol is WORSE than crack, then crack is okay too. In this way, I think it is important to distinguish the difference between the effects a substance can have on the individual and the effects a substance can have on society, instead of just making a general and, in my opinion, misleading statement, like “alcohol is worse than crack”.

While it is true that alcohol can cause many negative affects on not only the body of the individual, but on society as well (for example, traffic accidents and deaths related to driving while intoxicated), it IS possible to drink alcohol at a safe and responsible level; whereas, it is NOT possible to consume illegal drugs like crack cocaine and crystal meth at a safe and responsible level.

Here is the article that I read in the newspaper, called “Alcohol worse than crack”: http://www.winnipegfreepress.com/world/alcohol-worse-than-crack-106469568.html. What are your thoughts on this article? Does the article make a fair statement in comparing the negative effects of alcohol and other drugs?

Airport Full-Body Scanners: Safety of Public or Personal Privacy?

There has been a lot in the news recently about full-body scanners at airports. The Transportation Security Administration has begun to use technologically advanced full-body scanners at airports for security purposes, and it is expected that much talk will ensue on the topic of these body scanners in 2010. These scanners have the ability to see beneath a person’s clothing in order to fully search a person for weapons. There are two types of full-body scanners. The first is the Millimeter Wave Scanner which looks like a very large cylindrical phone booth. The machine emits very high frequency radio waves that are able to pass through clothing and therefore, show a three-dimensional image of the body underneath. Anything that is not human skin that shows up on the image is a cause for concern. The other type of scanner is the Backscatter Scanner which looks like two large boxes for a person to stand between with their arms out. Backscatter X-Ray machines, in contrast to Millimeter Wave machines, create a detailed two-dimensional image taken from two sides of the body. It works on the principle of the Compton Scattering Effect, which refers to the type of scattering x-rays and gamma rays undergo when coming in contact with matter. In this way, the scanner emits high-energy waves that are able to penetrate clothing, but not human skin, therefore, detecting the radiation that reflects back from an object on the body to form an image showing only the unclothed human body and any weaponry or explosives that one may happen to have on them.

The idea that over the next ten years, these scanners are expected to increase dramatically scares many people. Though this is obviously a way to effectively and efficiently search people for any harmful objects or weapons that they may be carrying, many people believe it to be a violation of personal privacy. It has been called a “Virtual Strip Search”, in the way that it allows screeners to see a detailed image of a person’s essentially nude body, even though the person viewing the image is in an isolated room away from the security section, and the face of the person is blurred. The person viewing the image may also be able to access personal information about the person from the image; for example, they would be able to see if the person has a colostomy bag, a missing or prosthetic limb, or is transsexual. It is also questioned as to whether or not these body scanners break child pornography laws, and whether or not there are health risks associated with their use.

This subject became of interest to me because when I was coming back from Chicago, I had to use a Backscatter Scanner. At the time, I was not aware of what was actually being done, but once I researched the subject, I felt very uncomfortable and kind of violated. Though I do think it is a violation of privacy, and essentially, a strip search, I know that the purpose of the scanners is to more efficiently diminish the number of people allowed to board an airplane that are holding dangerous weapons, which is also extremely important. In this way, it is hard for me to say if the potential risks that can arise because of security checks that are not thorough enough outweighs the invasion of my privacy. I tend to think that the safety of all the people is the most important, and so I understand why full-body scanners would seem to be necessary and the most effective way to search people of any dangerous objects that they may be carrying with them; however, violation of privacy is also an important issue. What do you think about full-body scanners? Is being virtually strip searched acceptable if it can more easily increase the safety of the general public?

This article from The Globe and Mail talks about the airport body scanners in New York City, more specifically, the ones at the Kennedy International Airport. It brings up some of the concerns that I have talked about and explains how the scanners work: http://www.theglobeandmail.com/news/world/americas/nyc-airport-rolls-out-detailed-full-body-x-ray-scanner/article1769550/

Thank you!

Euthanasia: Science and Ethics Meet

Hello! So, I recently read a book called “Breathless” by Lurlene McDaniel that I found very interesting. It was centered around the topic of Euthanasia, which is a very controversial subject. First I will talk about the basics of the novel, and then about some of the research I did afterwards surrounding the subject. The story is basically about this boy named Travis, who is a champion athlete and seems to have all the opportunities in the world. One day when Travis, his sister Emily, his best friend Cooper, and his girlfriend Darla, all go to the lake for the afternoon, Travis notices a sharp pain in his upper leg, but still decides to show off by diving off of a huge cliff. He hears his leg crack and it is soon found out that he has bone cancer and a tumor in his upper thigh that will make it necessary for his leg to be taken off. All four of the main characters get a chance to tell the story from their point of view at different points in the novel, which is very interesting. Travis journeys through a dark time in his life, as his body no longer allows him to do what he loves most, or follow his dream of being a professional diver. As his situation worsens, many questions of morality and ethical matters are brought up, including and most predominantly, the idea of Euthanasia, or “mercy killing”. Everyone has beliefs, whether they be religious or moral, and everyone thinks they know the difference between right and wrong; but, I do not think anyone knows how they would feel about Euthanasia if it was being considered for themselves or for someone they love. In the novel, Travis’s situation gets so awful that he WANTS to be killed painlessly; but, because he is only 16, his parents are the ones with the final say on his life and death. It really made me think about what I would do if I was in Travis’s position, or the position of his family or friends. Would you let someone you love give up on life, if the only way they could live was to suffer? Or would you do anything to keep them alive, even if they would rather die? If the novel does not make a person lean one way or the other, it definitely makes you contemplate your thoughts on life, death, and morality.

After researching the topic of Euthanasia to find out a bit more about the scientific aspect of it, I came across something called Palliative Care which, opposed to Euthanasia, focuses on giving a person with a life threatening illness comfort and relief from suffering in order to improve their quality of living and dying. Usually, Palliative Care has positive connotations and Euthanasia has negative connotations. Palliative Care is a branch of medicine that focuses on end of life care. Its purpose is to keep the patient comfortable and pain free, despite their illness, and to improve the quality of life of the patient and their family. Some of the approaches used in Palliative Care include medication management of pain and other distressing symptoms, providing social, emotional, practical, and spiritual support, and helping caregivers. Scientific studies of Palliative Care treatment have shown that it can improve quality of life, reduce time spent in the hospital, preserve feelings of dignity, and possibly even prolong life. Unfortunately, good quality Palliative Care is not consistently available to people with terminal illnesses.

It is believed by MOST people that Euthanasia is murder, and therefore is not legal in all places; however, I tend to think that sometimes Euthanasia is the best way to quickly relieve someone from pain who is already on the path towards death, or who decides that they want to end their life. It is said that Palliative Care leaves the dying person with a higher sense of dignity, but in my opinion, in some cases it could be more dignified to die painlessly than to be hooked up to respiratory tubes, feeding tubes, or other forms of life support.

Euthanasia is a provocative subject through which science and ethics meet. This is merely MY opinion on the subject and some of the science behind it, so I will let YOU be the judge of whether it is right or wrong. What are your thoughts on Euthanasia and Palliative Care?

If anyone is interested in the novel, here is a link that shows the cover, a brief description of the novel, as well as an option to purchase the book from a bookstore of your choice: http://www.goodreads.com/book/show/5599045-breathless

Thank you!

Welcome!

Hello! I am a grade 11 student in Canada who will be posting blogs about world issues for my Current Topics in Science class. I plan on exploring and examining current issues that I may not necessarily be familiar with, so that I can become more aware of what is actually happening in the world, and more importantly, WHY it is happening. Hopefully I will be able to provide insightful thoughts and opinions about relevant subjects that can help myself and others better understand the world we live in. Thank you!