Acceleration

I share share a bit about acceleration and how to calculate distances/acceleration/velocity. Acceleration is the rate of change of velocity in time(can both be positive and negative in magnitude i.e retardation). Note: Acceleration is a vector which means having a magnitude and a direction.

Some things that are good to know for speed problems:

v = v0 + at

x= x0 + v0t + at²/2

v²=v0² + 2a(x-x0)

avg v = v + v0 / 2

v= velocity x = distance a = acceleration t= time where y0 denotes the initial y(for x,v)

For this case Acceleration is constant and the movement of the object must be in a straight line. Acceleration from gravity: 9.81m/s towards the center of the Earth.

Acceleration for an object moving in a circular motion:

v^2/r where v is the velocity and r is the radius of the circle the object is moving around.

Science Center

I went to the science center on 2th May. It was indeed a fun and enriching trip. We went around the exhibitions first. What interest me the most was the maths room where there were lots of interesting formulas such as e=mc2 and e^(i*pi) + 1 = 0 which I have no idea why. Besides going to the usual exhibitions that everyone have seen before, we also went to a science show which was about liquid nitrogen. Liquid nitrogen is a liquid colder than dry ice which boils at -196 degrees Celsius, so its actually boiling in room temperature. When we pour it on the floor, it instantly vaporizes. The experimenters also made a soft banana into a hammer by pouring liquid nitrogen on it, as the banana contains water which turn into ice, it becomes as hard as a hammer and successfully hammered a nail into a chair. But when they tried pouring liquid nitrogen on a flower, although it became hard, when we tried to hammer a nail into a chair, the flower shattered into pieces. This was because that the frozen flower was like a thin layer of ice, it is hard but brittle. Then, they poured liquid nitrogen on a rubber balloon, they used it as a nail and hammered it in. This was possible even though it did not contain water due to the properties of rubber, when rubber contracts, it loses its flexibility and becomes stiff. Next, they tried to contain liquid nitrogen, they poured some into a plastic container and capped it with a lid tightly but the lid still popped out. Then they poured some into a glass flask and covered the mouth with a balloon. The balloon inflated and finally burst. This was because when liquid nitrogen vaporizes, its volume increases by about 600 times. After that, they tried to squeeze in a lot of balloons into a small box by pouring liquid nitrogen on it, this was possible as the air contracts when it is cool and the balloon's volume becomes smaller. Then, they took out the contracted balloons and the air inside expanded and the balloon had a bigger volume. However, some of the balloons burst as the air inside expanded faster than the rubber becoming flexible. Finally, they created a giant cloud by pouring lots of liquid nitrogen into a big unsealed container and adding hot water to it, the liquid nitrogen vaporizes faster and created a gigantic cloud. As I was seating in the first row, I could feel the nitrogen vapor, it was very cooling and I could not see the thing in all of that cloud. In total, the trip was very fun and enriching, I hope to come here again.

Colour Blindness

When people are colour blind, they cannot distinguish between certain colours, especially red and green. Bus drivers, taxi drivers, pilots are dangerous jobs if you are colour blind as you can't differentiate green light and red lights and might crash into something. Being a member of anti-bomb squad is also dangerous as you can't differentiate the wires and when you cut the wrong one the bomb might explode. Furthermore, some types of engineering are unsuitable as you might put the wrong wire in the wrong plug which may cause a short circuit and a fire may break out.

Recommendation to test whether if you are colour blind:

http://www.toledo-bend.com/colorblind/Ishihara.asp is a fast and simple way to test if you are colour-blind. It only takes about a few seconds. The test is just to see a number in the pattern of dots. Best of all, it is completely free! Try it now!

Science Documentary

A few weeks ago, I watched a science documentary called Today I Died which is about the possibility of the brain living on and remaining conscious even after clinical death. There was a lot of case studies on people who had experienced near-death situations. Most of the patients described that they saw a tunnel of bright light approaching them which why it happens is explained in the documentary scientifically. Furthermore, the patients feel very happy and peaceful, which is because large amounts of brain morphine is produced when the patient is under lots of stress when they are dying thus, they feel happy. Another common sight was that the patient could remain conscious and see what is happening around them when they were under anesthetics and were supposed to be unconscious. Even though it was not mentioned in the documentary, I believe that the patients were conscious as the anesthetics only reached the other parts of the body besides the eyes and the brain or were not enough there. I have personally experienced this, when I fractured my arm and went to the hospital, I was put under anesthetics and became unconscious. However, after a while, I could see what was happening, the nurses were twisting my arm but I could not feel any pain and was unable to move my body. Lastly, about the case where a blind person could see when she was in a near-death situation, I believe she just imagined everything, as she has never seen how the world actually looked like and can only assume that to be the world when it is really not the case. However, humans still do not know much about the afterlife, thus everything has a possibility of happening. In conclusion, I have learnt a lot from this documentary and hope there comes a day where humans fully understand the afterlife.

Link to video: http://www.youtube.com/watch?v=IMGskL_bujE&feature=related

Term 3

This term, we finished up our physics and started on ecology. Ecology is quite easy for me as I have studied it in primary school and because the answers are very predictable. The only things you need to remember is the terms(predators,prey,producer,consumer,etc) and others is based on common sense. We also learnt about the carbon cycle and energy cycle. I got another A1 for my test :D

Term 2 Reflections

We have finally moved on to optics! Physics suit me better as it is more of a working out on the spot than remembering stuff, requiring more skill and less contextual knowledge. We learnt about converging lenses, reflection, refraction, total internal reflection though only reflection(there's only one thing to remember)was tested. Thus, I did pretty well and I got a A1.

Term 1 Reflections

Term 1 has been a decent term. We studied a lot about chemistry(chemical bonding, pH, atomic structure and the periodic table). I found the periodic table the hardest as you have to remember the atomic number, group, number of neutrons, electrons, etc. I found the lab experiments pretty cool and hope there will be more in the future. I have gotten a A1 in term 1's science test. Yay!

Introduction

This will be my LSS e-portfolio from now on! Although I have been inactive and only start to post now, I will try to remember the things that have happened from January till now. So, forgive me if I miss out anything!