National Vertical Marathon 2009

This year's national vertical marathon was held on 8 Feb 2009, Sunday, at Republic Plaza. Republic Plaza is 280 metres tall with 66 floors and 1 basement. It has 15 double-decker vertical lifts and is one of the three tallest skyscrapers in Singapore.

Links:

http://en.wikipedia.org/wiki/Republic_Plaza,_Singapore

Tallest buildings

There is a three-building tie for the tallest building in Singapore. They are:

1.OUB Centre 280 m, 63 floors

2.UOB Plaza 1, 280 m, 66 floors

3. Republic Plaza, 280 m, 66 floors


As for the world's tallest buildings, here they are!

1. Burj Dubai, Dubai, The United Arab Emirates
Built in 2009
162 floors, 818 m

2.Taipei 101, Taipei, Taiwan
Built in 2004
101 floors, 508m

3. World Financial Center, Shanghai, China
Built in 2008
101 floors, 492m

Bibliography:

http://en.wikipedia.org/wiki/List_of_tallest_buildings_in_Singapore

http://www.infoplease.com/ipa/A0001338.html

Volcanic eruption 5 times in a row

Alaska's volcano, Mount Redoubt, erupted 5 times over night after being extinct for at least 20 years. It sent ash up into the air at a height of more than 9 miles high into the air. It sent light dustings of ash down, This ash can cause irritation to eyes, injure skin and block breathing passages.

Lab Symbols Video

Hello, this is a funny lab symbols video from Youtube. The wording may be a bit faint though, so you might have to pause and rewind to see some parts clearly. Enjoy!

Between Physics and Chemistry

Most people know about the famous coke and mentos issue. However, do you know why? This Mythbusters video explains in detail. Unfortunately, I could not embed it here due to company policies of Discovery Channel.

http://www.youtube.com/watch?v=kMXPOqovSBs

Basically, this is what happens:

The ingredients required to create the sensational explosion is as follows.

1. CO2 gas found in soft drinks

2. Artificial Sweetener (which is why diet coke is better than normal coke)

3. Gum Arabic

4. Gelatin

5. The process of Nucleation. Mentos surface is full of tiny craters, and during this process the aforementioned ingredients interact with each other, causing the CO2 to escape to the surface. This is evident from the fact that non-mint mentos, with a waxed surface, reacts very slowly or not at all as the wax covers the craters.

This is also linked to Ms. Liang's post on the discussion forum. Ms. Liang posted on the discussion forum about a Pepsi and Necco wafer experiment. According to the video, Necco wafers release the hydrogen component from hydrogen hydroxide, which is a fancy name for water. Hydrogen is highly flammable, thus fire can form on the surface of the glass.

Necco wafers consist of: sugar, corn syrup, gelatin, gum, colorings and flavorings. From the ingredients, you can tell that Necco wafers are more of powdery candy than wafers as there is no flour in it. I think this would be an interesting experiment to try. However, Necco wafers are manufactured in the USA, so it would be hard to obtain them here in Singapore. Thus, to try this experiment, one could just add gum and gelatin to Pepsi as the other ingredients are redundant. These are pics of necco wafers below.

I think I will try this when I have the time an post more about it.

Links:

http://www.necco.com/OurBrands/Default.asp?BrandID=7

http://www.youtube.com/watch?v=kMXPOqovSBs

http://www.maniacworld.com/pepsi-and-necco-wafers.html

Convection currents

Today Mr. Lim talked about convection currents in class. He posed two questions for us: 1. Since warm air rises and and cold air sinks, will a taller person feel colder than a short person? 2. based on the same concept, will people on the 40th floor feel warmer than on the 15th floor? If yes, why do people claim to feel "cooler" on the uppermost floors?

I think that a tall person would probably feel warmer. This is because they are higher up and the warm air will circle around them. Surprisingly, I have also observed this very often: My taller friends would be sweating profusely, while my shorter friends are huddling together trying to get warm!

As for the second question, I don't think it makes a difference since every level has air-conditioning! As for people feeling "cooler" on the top levels, it is because that is where the cooling unit for the entire building is.

Ice, Water, salt and Ice cream

I have mentioned this very briefly in one of my earlier posts, entitled Measurements and Density. This time, I shall post more about it. Firstly, the density of ice is less than that of water. This is obvious as ice cubes float in a glass of water when you put them in. Simple right? But why is this so? Well, the answer is simple: When water freezes to form ice, it traps air in it. Air is less dense than water, so it causes the ice to float.

Secondly, if a glass is filled with water and ice cubes are placed in the glass, when the ice cubes melt will the water level rise? The answer is no, the water level will NOT rise. At first, I also thought that the water level would rise. However, once I read the explanation, it made perfect sense. The reason is that when ice melts, its volume is still the same so it will take up the same amount of space that it took up when it had not melted yet.

Lastly, we were asked to research on the effects of impurities on water. Well, this is what I know: In cold countries, salt, an impurity, is thrown on the roads to melt the snow and ice. This is because impurities lower the melting point of ice. This same concept is applied to make ice cream. You can just pour sugar and milk into a freezer bag and seal it, then place it into a larger bag, already filled with crushed salt. Make sure both bags are tightly sealed, and then shake the bags vigorously(but not so vigorously that they split open or smash!) After some time, the contents should solidify and turn into delicious homemade ice cream!

I found a video on Youtube summarising the above instructions in a 1min 18 sec clip. Enjoy!

http://www.elmhurst.edu/~chm/vchembook/122densityice.html

http://sg.answers.yahoo.com/question/index;_ylt=AqAdCXkAnMkY8xceJjXqoAQh4wt.;_ylv=3?qid=20080208133726AAWySCd

http://www.wikihow.com/Make-Ice-Cream

Challenger disaster

I read about this and decided to post it, not just because it is related to thermal physics, it also shows how ignorant Man is.

On January 28, 1986, the Challenger was supposed to conduct the TISP (Teacher in Space Program). In other words, for the very first time, a teacher would be boarding the Challenger to visit space. However, the temperature was too cold (29 degrees F). The engineers who made the Challenger told the NASA managers that they should wait until the temperature reached 58 degrees F. This is because the low temperatures might cause the O-rings to not seal properly. The O-rings kept hot gases, preventing them from escaping.

However, NASA really wanted to launch the flight, so the managers decided to give the go-ahead anyway. Just as Challenger was pulling away from Earth, one of the O-rings failed to seal, causing the hot gas to escape. Flames shot out from one slide of the rocket and licked at the hydrogen tank. Seconds later, the tank exploded, and all seven crew members, including the teacher, died on the spot.

This shows how important it is to consider the safety facts instead of rushing into things. Due to the cold weather, the O-ring had contracted and became too stiff to seal properly. This caused 7 innocent people to be killed.

This is a video showing the live recording of the Challenger explosion.