Hydrogen, Plutonium and Uranium Bombs

1. Hydrogen bomb

These bombs are made from the isotopes of hydrogen. However, unlike what I originally thought, the hydrogen bomb was NOT used to end World War 2. In fact, the first hydrogen bomb was only detonated on November 1 1952, several years AFTER the end of World War 2. Oops!

2. Uranium bomb

A uranium bomb is created by a slow and complicated process. First, you need to obtain uranium which is highly enriched with over 90% U-235. This poses a problem as most uranium contains 0.7% U-235 at most. This is fortunate as it has helped to control the development and usage of nuclear weapons so far.

Once the required mass is obtained, it must be kept in at least 2 separate pieces until the moment of detonation, the pieces are then forced together quickly, causing an almost instantaneous and powerful explosion.

The first uranium bomb, nicknamed "Little Boy", was dropped on Hiroshima on August 6 1945.

3. Plutonium Bomb

Plutonium-239 is used to make plutonium bombs. This type of bomb is similar to a uranium bomb. However, very little plutonium-239 exists in nature. Unfortunately, plutonium-239 is easily produced by breeder reactors, which generate manmade plutonium-239.

The first plutonium bomb, nicknamed "Fat Man", was dropped on Nagasaki on August 9 1945, leading to the end of World War 2.

Sources:

http://hyperphysics.phy-astr.gsu.edu/HBASE/nucene/bomb.html

Crystallisation

Here is an interesting video explaining crystallisation. It is a silent video but the images speak for it.

Separating Mixtures

Here are some ways to separate the following mixtures:



1) A mixture of non-magnetic materials and iron



Method: Use a magnet



2)A mixture of water, a solid that can dissolve in water and a solid that cannot (eg. water, salt and sand)



Method: filter the mixture to remove the sand, then use distillation to separate the salt and the water



3) 2 liquids that do not mix (eg. water and oil)



Method: Slightly more complicated. There is a special machine built to do so. It is called the API oil-water separator. You can find out about it in Wikipedia at this site: http://en.wikipedia.org/wiki/API_oil-water_separator



4) Air and petroleum

This is definitely more difficult... There is a special type of machine that is used. It is big, bulky and complicated. You can see it at these sites:

http://www.onyxnet.co.uk/clients/mastrad/bub.htm

http://www.geneq.com/catalog/en/air_release_petro.html

The aftermath of coke and mentos

Hi people, these are some choice pics from the coke and mentos experiment. Also, here is the wrap-up of our group's experiment.

Group members: Sarah Tay, Rachel Seah, Stella (who, by the way, took all the photos, thanks!) and me

Objective: To find out how the number of Mentos affects the height of the fountain.

Hypothesis: The more mentos put in, the higher the fountain will go.

Items used: Several tubes of mentos, three bottles of 1.5 litre coke, two meter rulers, two measuring cylinders, one of which got jammed, and one poncho that made me look like Little Red Riding Hood.

Procedure: We were supposed to drop in 10, 20 and 30 mentos respectively into each bottle of coke, but for the first one, Sarah only managed to unjam 2 mentos, so the rest were stuck when the explosion occurred.

Secondly, Sarah managed to fit 16 mentos into the measuring cylinder and pour it all in at once. Stella expertly captured a shot of the coke in mid-air.

Finally, we put in 10 mentos at once. Of course, being me, I put the stupid ruler crooked so the reading was inaccurate.

Our final conclusion was that we were correct, but up to a certain point the coke would stop dissolving the mentos and we would need to add more coke instead.

Here are explosion pics of other groups.

Separation of mixtures

How to separate mixtures:

1. Hand Separation

Example: Separating salt and sand

2. Filtration

Example: Sand and Water

3. Distillation

Example: Alcohol and Water

4. Chromatography, for separating different substances to determine whether they are banned substances

5. Etc. There are a whole lot of other techniques but they are too complicated and not required at this level.


http://www.chemteam.info/Matter/SeparationOfMixtures.html

The Elements

The periodic table of elements was thought up in 1869 by the Russian Chemist, Dmitri Mendeleev. They are in this order: 1. Hydrogen 2. Helium 3. Lithium 4. Beryllium 5. Boron 6. Carbon 7. Nitrogen 8. Oxygen 9. Fluorine 10. Neon 11. Sodium 12. Magnesium 13. Aluminium 14. Silicon 15. Phosphorus 16. Sulfur 17. Chlorine 18. Argon 19. Potassium 20. Calcium


















Also, for those who enjoyed Miss Liang's elements song in class today, I am posting a video, probably by the same makers of Li Shan's Newton video as both use Lego.

Bibliography



http://www.flickr.com/photos/dullhunk/2053007240/



http://en.wikipedia.org/wiki/Periodic_table_%28large_version%29



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

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