Reflections on Lab Sessoins

Since I was in Secondary 1, I have always loved science practical lessons. I find them very interesting as it gives us an opportunity to try out first hand what we had learned in the classroom. For example, we have been taught that to test for hydrogen gas, we can use a lighted wooden splint. If it goes out with a "pop", we can confirm that there is hydrogen gas. Just learning this on black and white would be ineffective in teaching us. With the lab session, we would be able do the experiment ourselves and see the wooden splint "pop".

Besides being more effective in teaching us, lab sessions are also fun and interesting. We can mix chemicals, heat substances and so on. It is very fun to me to watch chemicals change colour or even change state. It allows me to see the other side of science, unlike the boring primary school science where there is only memorise and memorise.

There were no science lab sessions during term 3 as we were focusing on biology where there weren't many experiments to do. There were also no science excursions organised so far. However, there will be a field trip to Macritchie in term 4 and I am looking forward to it. I hope that there would be more science lab lessons and more fun and interesting science experiments.

Term 3 Reflections

In term 3, we spent half a term learning physics and the rest of the term learning biology. Term 3, compared with term 2, was quite simple. We continued to study lenses and colours of light. Lenses was just a revision on refraction, as convex lenses converges light through refraction. Lenses was not very hard to me as I had already knew refraction well. I just had to memorize at which position of the object to the lens would cause the image to be produced at which position. It wasn't very hard but it took some time to memorise everything.

Next, we learned on colours of light. Just like lenses, we just had to memorise what colours would be produced when two colours are mixed together. For example, red and blue makes magenta while red and green makes yellow.

Following that, we moved onto biology. We learned ecology followed by sexual reproduction. Ecology was not really very difficult as it was just food chains and food webs. These diagrams are straight-forward and does not really involve much thinking. However, we need to understand why the food chain is a delicate balance and that the absence or addition of another animal might destroy the food chain. We also must know what abiotic and biotic factors mean. These are the 3 topics tested for the term 3 test.

After the test, we continued with biology and studied on sexual reproductions. It is a new topic to me and I think it involves a lot of memorising too, such as all the body parts and their uses. I have not really studied sexual reproductions yet, thus I an not really familiar with it. I often have to check the notes before I can do the worksheets.

In conclusion, term 3 was much easier than term 2 and I still scored a A1 for my test. :) However, I cannot feel too contented and I must always work hard to keep my good grades.

Term 2 Reflections

In term 2, we studied physics, reflection and refraction. Reflection was no problem as it was quite straight forward. However, it took me quite a while to get a hang of refraction. It was the first time I ever heard of refraction and it was quite complicated. Though the topics tested this term was hard, I still managed to get a A1 for science that term. I would try my best and do well for the subsequent tests. 

Reflection was no trouble for me as it was easy and straight-forward. There are two laws of reflection: 

     1) The incident ray, reflected ray and the normal to the reflecting surface all lie in the same plane. 

     2) The angle of incidence is equal to the angle of reflection. 

There are also two types of reflection, regular and diffuse. Regular reflection occurs on smooth surfaces such as mirrors and polished metals. For these surfaces, parallel incident rays are reflected in one direction only. All these rays would also have the same incident and reflected angles. Diffuse reflection occurs on rough surfaces such as sandpaper and clothing. Parallel incident rays are reflected in all directions, different from those of regular reflection. 

Refraction was a challenge to me. Refraction is the bending effect of light as it passes from one optical medium into another. Light travels at different speeds in different optical mediums. A sudden change in speed of light would cause the path of light to bend. Light refracts away from the normal when light passes into an optical less dense medium and refracts towards the normal when it passes through an optical denser medium. 

At first, I found it very confusing and could not understand why. But after a lot of practices and experiments, I finally got the hang of it and did well. After this term of science lessons, I noticed that physics involves and a lot of calculations and drawings. We have to be precise in our drawings and clearly draw how light travels. 

The Beneficial yet Hazardous Nuclear Energy

Nuclear potential energy is the potential energy inside of an atomic nucleus. The nuclear particles are bound together by a strong nuclear force. The uranium found in the nuclear power plant reactor core is used for heating up the water. The uranium is heated and it turns the water into steam which turns the turbine. The turbine then produces electricity. In the world, there are about 443 operating nuclear power plants, accounting for 14 percent of the world’s electricity and 6 percent of the world’s energy.

On March 11 2011, an earthquake and a tsunami caused 3 nuclear reactors in Fukushima, Japan, to be severely damaged, causing world-wide panic and chaos. This was not the first time a nuclear incident has happened and this accident has caused economic, political and biological problems. Many people have died during all of these accidents and even though 25 years has passed since the accident, Chernobyl, Ukraine is still restricted to the public. However, although nuclear power has many disadvantages, it still has its good points. Nuclear energy is still controversial and there is still an ongoing debate about the use of nuclear energy.

Nuclear energy is a sustainable energy source that also reduces carbon emissions. As nuclear power does not involve burning of coal or fossil fuel, no carbon dioxide is produced and released into the air. Only uranium is used in nuclear plants so it is said that nuclear energy is clean. Global warming is starting to become a bigger problem and many countries have already started planning on saving carbon emissions. Nuclear power may be one good way to cut down on carbon emissions.

However, after the fuel rod has been used and there is no more nuclear energy left in it, it cannot be used and must be disposed. However, even though it does not have any nuclear energy left in it, it is still very dangerous and radioactive. These fuel rods must be disposed of properly and carefully or else some of the nuclear radiation would leak out. The United States’ plan of disposing these fuel rods is by burying it under the ground and wait for it to decay off. However, it takes tens of thousands of years for these fuel rods to decay off and the number of fuel rods the United States have used can cover a football field, one metre in depth. This issue is still being debated about and it is very important that scientist find out how to dispose of them quickly.

Reflection

Recently, Singapore is debating on whether it should build a nuclear power plant to provide energy for the country. After the disastrous nuclear accident in Japan, I feel that the answer is quite clear. Singapore is such a small country. Imagine the amount of nuclear radiation the locals would experience. Also, if there were a similar accident in Singapore, the whole country would become a wasteland and all the locals would contact a lot of harmful radiation. Singapore is such a small country compared to Japan, and their country is in ruins now. Imagine what would happen to Singapore. In conclusion, building a nuclear power plant in Singapore is too risky and dangerous.   

Electromagnetic Spectrum

The electromagnetic spectrum is basically the range of all possible frequencies that exhibit wave-like behavior as it travels, such as light. The electromagnetic spectrum extends from very low frequencies such as modern radio to very high frequencies, such as gamma radiation. The wavelength of modern radio covers thousands of kilometres while the wavelength of gamma radiation is a fraction of an atom.

James Clerk Maxwell was the first person to discover electromagnetic waves. He calculated the speed of electromagnetic waves using the wave equation and found out that the speed of light coincided with the speed he found, thus he concluded that light was an electromagnetic wave as well. Other electromagnetic waves include, in order of lowest frequency to highest frequency: radio frequency, microwave, far infrared, mid-infrared, near infrared, visible radiation (light), ultraviolet light, X-rays and gamma rays.

Visible light, or visible radiation, has a wavelength of between approximately 400 nanometers to 700 nanometers and it can be directly perceived by the human eye. Other wavelengths, such as nearby infrared (longer than 700 nanometers) and ultraviolet (shorter than 400 nanometers), cannot be seen with the naked eye.

Radio waves are used to transmit data or information. It is usually used by antennas, such as the ones on cars or on radios. Microwaves are super high frequency or extremely high frequency.

Microwaves use volumetric heating which transfers energy through the material electromagnetically, unlike the normal heating, thermal heat flux. The benefit of this is that it is a more uniform heating method and it also reduced heating time.

Terahertz radiation is a region of the spectrum between far infrared and microwaves. This range has rarely been studied as it is at the high end of the band. However, scientists hope to apply terahertz radiation in the armed forces, where the high frequency waves may be able incapacitate the enemies’ equipment.

Infrared light has a wavelength longer than that of visible light and it is most commonly used in infrared cameras. Infrared is used in night vision when there is insufficient visible to see. The infrared night vision devices increase in-the-dark visibility without actually using a light source. Infrared radiation can also determine the temperature of objects. Different temperatures display different colours on a infrared camera, an example would be that thermographic image of a dog.

            Ultraviolet light have wavelengths shorter than visible light but longer than X-ray. UV light is very “energetic” and can easily break chemical bonds, making molecules unusually active or ionizing them. Sunburn is a cause of UV radiation. UV radiation causes disruptive effects on skin cells, which could cause skin cancer. The sun emits a large amount of UV radiation, and it could turn the earth into a barren desert; but the Earth’s ozone layer absorbs it before it reaches Earth.

           

            X-rays are also ionizing, but their higher energies can also allow them to interact with matter. As X-rays can pass through most objects, they can be used to “see through” objects, which can be used in medicine.

           

            Lastly, gamma rays are the most energetic photons, having no defined lower limit to their wavelengths. Not many scientists have research on this topic but they are most used to astronomers in the study of high energy objects or regions. Gamma rays are also used for the irrational of food and seed for sterilisation.

            

            In conclusion, I have learnt a lot from this assignment. I learned more about the electromagnetic spectrum and all the frequencies that fall under it. I have also learned more about the different types of light such as visible light and infrared light. 

Medical Breakthroughs 2011

Recently, I read an article on Reader's Digest on some of the biggest health news of the past year. Reader's Digest went out and asked many leading doctors and researchers around the world what discoveries, drugs and medical devices made them more excited. The answers they got were surprising and even I could hardly believe my eyes as I read through the article. Now, let me share with you some really interesting and astounding breakthroughs we made this year.

Recently, doctors invented an artificial heart to replace hearts of patients. It is the first ever total artificial heart that totally replaces the entire heart. Before this, ventricular assist devices were placed into the heart to help kick-start it. Now, the entire heart can be removed and can be fitted with the device. Over a thousand people had been implanted with this device and survived. At first, I did not believe it. Taking out the entire heart, and putting in an artificial one? This is totally absurd. But after reading on, I found out that many people have been treated this way and they have a "new" life. Clearly, technology has greatly advanced and people may now have an artificial heart.

Secondly, after ten years of work, a group of optometrist finally succeeded in in creating a cornea from yeast. Corneal scarring or clouding is a major cause of blindness around the world, and in many countries there is such a shortage of donated corneas that people have to wait two to three years for a transplant. In order to tackle that problem, this group of optometrists went out and invented an artificial cornea from yeast. After a clinical trial, ten patients underwent surgery and six out of ten patients' vision was comparable to conventional corneal transplantation.

Reflection
The article also mentioned many other discoveries such as using cockroaches brain to kill bacteria and virtually "printing new skin".  However, I wonder: Are all these new inventions and discoveries morally correct? We humans have invented artificial corneas and hearts and are even able to heal burns faster by using a printer to "print" new skin cells. I think that is this goes on, we would soon turn ourselves into robots, with a artificial heart and other artificial body parts. We were born and made with a real heart, and yet humans are trying to act god and replace our natural heart with artificial hearts. Is that morally correct?