Thursday, April 30, 2009

Crystallisation

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

Tuesday, April 21, 2009

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

Saturday, April 18, 2009

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.

Tuesday, April 7, 2009

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

Friday, April 3, 2009

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