Definition: An object stays in the same form (at rest or moving) in the same speed and direction unless acted upon by a unbalanced force.
Have you ever wondered why your body moves forward when a bus brakes and why your body tends to lean back when the bus speeds up? This is because be it an object or a living thing, we tend to "keep on doing what we are doing", which means that we tend to want to stay in the position we are in. The force of the road on the locked wheels provides the unbalanced force to change the car's state of motion, however we have no unbalanced force to change our state of motion. Thus, when the car breaks, we continue in motion, making us lean forward. In this case, seat belt is invented which would provide the unbalanced force to bring us to a state of rest from a state of motion. However, what is unbalanced forces which was used throughout the explaination?
Unbalanced forces are two forces of equal magnitude and are in opposite directions balancing each other. An example is when a book is resting on a table. The two forces involved are the table which pushes the book upwards and the gravity pull which pulls the book downwards. The book is said to be at equilibrium. There is no unbalanced forces acting on the book, enabling it to maintain its state of motion (when all the forces acting on the book are balanced, there is no unbalanced force and thus the book maintains its state of motion).
However, if a person pushes the book and made it accelerate forward, the object is said to be acted upon as there is no other force with equal magnitude and in the opposite direction to balance the unbalanced force.
Reflections: I feel that this topic which have not been taught yet, is quite easy to understand and also very interesting. I chose this topic because I am very puzzled by the fact that when a bus accelerates, my body moves backwards instead of moving forward and vice versa. As I was searching on the internet for the answer, I found this interesting topic- law of inertia. I decided to research more on it and finally found the answer to it. I will continue to research on topics which are linked to our lives as I find them very captivating and I hope you will look forward to my next post!
Sources: http://www.physicsclassroom.com/class/newtlaws/u2l1d.cfm#balanced
http://www.physicsclassroom.com/class/newtlaws/u2l1a.cfm
Tuesday, March 29, 2011
Saturday, March 12, 2011
Term 1 Test 1 Reflections
Firstly, I am not very happy with my science results although I got 36/40. This was because I could have gotten first in class with a score of 39/40. There is 3 questions from the MCQ which I knew how to do but was careless. Nevertheless, I have already understood the whole test. This was what I feel is most important in learning-understanding and learning from your mistake. I would not make the same mistakes again after understanding them and I am quite confident in scoring full marks if I were to encounter the questions again.
Next, I would like to talk a little bit on my study method. I feel that this study method of now should be changed as it is just last minute revision by writing down all the notes on the textbook, powerpoint slides and worksheets. This gives me an opportunity to read through them thrice before them. 3 days before the test, I did not really understood the topic and could not even differentiate proton number with mass number etc. However, this method of mine is not bad if I were to start preparing before the test. I would not repeat this mistake again and look forward to the next test.
Next, I would like to talk a little bit on my study method. I feel that this study method of now should be changed as it is just last minute revision by writing down all the notes on the textbook, powerpoint slides and worksheets. This gives me an opportunity to read through them thrice before them. 3 days before the test, I did not really understood the topic and could not even differentiate proton number with mass number etc. However, this method of mine is not bad if I were to start preparing before the test. I would not repeat this mistake again and look forward to the next test.
Saturday, March 5, 2011
Sneezing Myths and Facts
Why do we sneeze?
Ans: The medical term for sneezing is “sternutatory reflex”. Sneezing places a lot of stress on the body and air pressure is also place on the eyes. Sneezing is stimulated by a tickle in the nose. It helps us to clear germs and bacteria in our nose, at the same time, take in oxygen. Sneezing is something we have no control over.
Myths and Facts of Sneezing
People believe that sneezing has so much pressure that it pops your eyes out and may be deadly while others think that it is just a reflex and some people can even sneeze with their eyes open. Others think that we close our eyes when we sneeze because our body wants to protect our eyes from the germs and bacteria released from our nose by the powerful sneeze.
So... which belief is true?
The website http://library.thinkquest.org/J0112390/sneezing.htm feels that sneezing is a reflex and so is our eyes and that we have no control on whether we can close our eyes or not when we sneeze.
It feels that people who do not have reflex can sneeze with their eyes open while others try to close their eyes to prevent their eyes from popping out.
It also feels that "Your eyes don't really pop out" when we sneeze.
This website disagrees with the fact that people close their eyes to prevent the germs and bacteria which is released from the nose after sneeze from affecting the eyes. It feels that our eyes is constantly in contact with germs and bacteria all the time.
The website http://www.answerbag.com/q_view/22468 has comments of many internet users.
One strong quote from this website is "It is unclear, but scientists theorize that we close our eyes to protect them. We may be protecting our eyes from microorganisms and particles from our sneezes," said Dr. Bonnie Henderson, director of comprehensive ophthalmology at the Massachusetts Eye and Ear Infirmary.
Others feel that it is a natural human instinct to prevent our eyes from popping out.
Another user feels that the air pressure our eyes experience is not strong enough to pop our eyes out.
In contrast, a different user states the evidence of Adolf Hitler making use of sneezing as a torture tactic by forcing his prisoners' eyes to open with toothpicks and sprinkling pepper under their noses to make them sneeze. This made their eyes partially pop out.
Many different people have many views and evidence for the fact of closing our eyes when we sneeze. However, which do you think is true? A warning to readers: Please do not try sneezing with your eyes open as it may really just pop your eyes out.
Reflection/Feelings:
I feel that sneezing would really pop our eyes out as it is strongly supported by the torture tactic Adolf Hitler used on his prisoners. As this is most probably recorded in history, it is more truthful and reliable. Like what my primary school science teacher said, sneezing is a kind of reflex which is so strong that it may pop your eyes out. I did not believe her initially but believed her after researching. Although there are other views on the facts about sneezing, I feel that the most convincing one would be that if you open your eyes when sneezing, your eyes would pop out. It is actually up to individual's beliefs and no one really knows the fact behind it. Nevertheless, sneezing would definitely benefits our body.
Source:http://www.answerbag.com/q_view/22468
http://library.thinkquest.org/J0112390/sneezing.htm
Ans: The medical term for sneezing is “sternutatory reflex”. Sneezing places a lot of stress on the body and air pressure is also place on the eyes. Sneezing is stimulated by a tickle in the nose. It helps us to clear germs and bacteria in our nose, at the same time, take in oxygen. Sneezing is something we have no control over.
Myths and Facts of Sneezing
People believe that sneezing has so much pressure that it pops your eyes out and may be deadly while others think that it is just a reflex and some people can even sneeze with their eyes open. Others think that we close our eyes when we sneeze because our body wants to protect our eyes from the germs and bacteria released from our nose by the powerful sneeze.
So... which belief is true?
The website http://library.thinkquest.org/J0112390/sneezing.htm feels that sneezing is a reflex and so is our eyes and that we have no control on whether we can close our eyes or not when we sneeze.
It feels that people who do not have reflex can sneeze with their eyes open while others try to close their eyes to prevent their eyes from popping out.
It also feels that "Your eyes don't really pop out" when we sneeze.
This website disagrees with the fact that people close their eyes to prevent the germs and bacteria which is released from the nose after sneeze from affecting the eyes. It feels that our eyes is constantly in contact with germs and bacteria all the time.
The website http://www.answerbag.com/q_view/22468 has comments of many internet users.
One strong quote from this website is "It is unclear, but scientists theorize that we close our eyes to protect them. We may be protecting our eyes from microorganisms and particles from our sneezes," said Dr. Bonnie Henderson, director of comprehensive ophthalmology at the Massachusetts Eye and Ear Infirmary.
Others feel that it is a natural human instinct to prevent our eyes from popping out.
Another user feels that the air pressure our eyes experience is not strong enough to pop our eyes out.
In contrast, a different user states the evidence of Adolf Hitler making use of sneezing as a torture tactic by forcing his prisoners' eyes to open with toothpicks and sprinkling pepper under their noses to make them sneeze. This made their eyes partially pop out.
Many different people have many views and evidence for the fact of closing our eyes when we sneeze. However, which do you think is true? A warning to readers: Please do not try sneezing with your eyes open as it may really just pop your eyes out.
Reflection/Feelings:
I feel that sneezing would really pop our eyes out as it is strongly supported by the torture tactic Adolf Hitler used on his prisoners. As this is most probably recorded in history, it is more truthful and reliable. Like what my primary school science teacher said, sneezing is a kind of reflex which is so strong that it may pop your eyes out. I did not believe her initially but believed her after researching. Although there are other views on the facts about sneezing, I feel that the most convincing one would be that if you open your eyes when sneezing, your eyes would pop out. It is actually up to individual's beliefs and no one really knows the fact behind it. Nevertheless, sneezing would definitely benefits our body.
Source:http://www.answerbag.com/q_view/22468
http://library.thinkquest.org/J0112390/sneezing.htm
Tuesday, March 1, 2011
Osmosis & Diffusion Science Experiment
Materials needed:
Potato strip
Concentrated Salt Solution
Weighing Machine
Steps/Procedure:
Put the potato strip into the concentrated solution for 10 minutes, taking out the potato strip from the concentrated salt solution every 2 minutes to weigh the potato strip. The potato strip would shrink and the weight of the potato strip would decrease steadily.
Explaination:
Osmosis moves down a water potential gradient, with a partially permeable membrane (potato) in this case. The potato strip has higher water potential than the concentrated salt solution. Therefore, the water/moisture of the potato strip moves out of the potato strip to the concentrated salt solution until the water potential are about the same.
Reflections:
As I feel that this topic would be taught this year, I read up on the topic first and understood it. Next, to further understand the experiment, I did an experiment. By doing this, I could really remember the theory behind it as I have done hands-on and captured the theory into my brain. This experiment is truely enriching as it is not only fun, enjoyable, but helps to learn as well.
Potato strip
Concentrated Salt Solution
Weighing Machine
Steps/Procedure:
Put the potato strip into the concentrated solution for 10 minutes, taking out the potato strip from the concentrated salt solution every 2 minutes to weigh the potato strip. The potato strip would shrink and the weight of the potato strip would decrease steadily.
Explaination:
Osmosis moves down a water potential gradient, with a partially permeable membrane (potato) in this case. The potato strip has higher water potential than the concentrated salt solution. Therefore, the water/moisture of the potato strip moves out of the potato strip to the concentrated salt solution until the water potential are about the same.
Reflections:
As I feel that this topic would be taught this year, I read up on the topic first and understood it. Next, to further understand the experiment, I did an experiment. By doing this, I could really remember the theory behind it as I have done hands-on and captured the theory into my brain. This experiment is truely enriching as it is not only fun, enjoyable, but helps to learn as well.
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