Sunday, September 4, 2011

Atomic Structure

We all know that everything is made of atoms right? Atoms come form the Greek word atomos, which means uncuttable, indivisible, or something that cannot be divided further. However, we all know that atoms are not the smallest things in existence. There are subatomic particles, namely electrons, protons, and neutrons. Electrons in an atom orbit a central nucleus, made up of protons and neutrons. The number of protons, neutrons, and electrons depends on the element in question. Most of the atom is actually empty space, which kind of makes us all made up of...empty space?? But that's not all. Within all those electrons, protons, and neutrons, there are even more sub-subatomic particles! They are called quarks. currently there are only 6 types of quarks found - up, down, strange, charmed, top, and bottom quarks. Scientists believe that there are particles even smaller than quarks, but that has not been proven. 

So now you know, the building blocks of everything in the universe, and how we are all technically made up of empty space :)

Saturday, September 3, 2011

Acids & Bases

To the layman, an acid is a corrosive liquid that dissolves everything it makes contact with, and is extremely dangerous and scary. However, acids and bases are not as scary as Hollywood makes it out to be. In fact, we are surrounded by acids and bases. That said, in a laboratory, acids and bases, like anything else, must be treated with caution.

An acid is a substance that ionises in water to produce hydrogen ions ( H+ ).

A base is any metal oxide or metal metal hydroxide. Alkalis are soluble bases. Alkalis ionise when they dissolve in water to form hydroxide ions ( OHˉ )

There are also various reactions with acids and bases:
1. Acid + Metal  → Metal Salt + hydrogen gas.
Eg. Hydrochloric acid + Magnesium → Magnesium Chloride + Hydrogen gas.

2. Acid + Base → Salt + Water
Eg. Sulfuric acid + copper (II) oxide → Copper (II) Sulfate + Water

3. Acid + Carbonate compounds → Salt + Carbon dioxide gas + Water
Eg. Hydrochloric acid + Sodium bicarbonate → Sodium Chloride + Carbon dioxide gas + Water

4. Alkali + Ammonium compound → Salt + Ammonia gas + Water
Eg. Sodium hydroxide + Ammonium chloride → Sodium chloride + Ammonia gas + Water

And there you go, the 4 types of reactions involving acids and bases.

Acids and Alkali are actually more common that you think. Common examples of acids include:
ethanoic acid, found in vinegar
citric acid, found in citrus fruits like oranges, lemons, and grapefruit.
lactic acid, found in sour milk and yogurt
tannic acid, found in tea
and finally tartaric acid, found in grapes.

As you can see, not all acids are dangerous. Some acids are actually harmless to us. So next time you think of an acid, think of your very harmless citrus fruit ;)

Friday, September 2, 2011

Carbon Cycle

The is one of the most important cycles of the earth and allows for carbon to be recycled and reused throughout the biosphere and all of its organisms. Carbon in the air in the form of carbon dioxide is taken in by plants for photosynthesis. The carbon is then converted into glucose. When these plants are eaten, the glucose is transferred to them. When the plants and animals die, their bodies decay, bringing carbon to the ground. Some of it becomes buried deep underground and become fossil fuels after millions of years. Also, every time an organism respires, they release carbon dioxide into the atmosphere, restarting the carbon cycle
This topic is one that I had no idea at all. I never knew that there was such a thing as a carbon cycle, so this topic showed me just how much about science I do not know.

Wednesday, August 31, 2011

Properties of Light

Properties of Light includes reflection and refraction of light, as well as lenses. Although light travels in a straight line, reflection and refraction are able to change the direction of light. Reflection is when a ray of light is hits a medium and is "thrown back" in the direction of its source. Refraction is when the ray of light goes through a denser medium and bends. The study of lenses is just a more specific study of refraction. All these are new to me, as I never imagined that light could change direction. It is a really interesting topic and was a real eye-opener to me

Term 3 Science Test

This term, I got 30.5/40 for my test. The topics were Ecology and properties of Light. actually I am quite satisfied with this mark, as I thought the test was quite difficult and I could not get an A1. Also, not as many people in my class got an A1, which translates into an improvement in terms of class ranking. So now I am feeling very happy with myself, although I can still improve more...

Term 2 Science Test

This term, i got 34/40 for my science test. Better than last term, but still not as good as many of my classmates.Although i studied for all my topics for this test, this test I still did not manage to do as well as others due to more carelessness on my part. I failed to check my test because I barely completed my paper in time, and hence I had no time to check my answers. After this test I realised that I need to manage my time better and not spend my time pondering too much on difficult questions.

Tuesday, August 30, 2011

Term 1 Science Test

In my term 1 science test, i got 32/40, or an A1. however, most of my class also got an A1, and most of them got higher than me. That is saddening. I realised that I did not study the topic acids & bases, and therefore lost many marks on that topic, while those who got higher than me studied that topic, and as a result did better than me in this test. I thought that acids & bases would not be tested, and hence I did not study for them. I learnt that I should revise on all that I learnt in class, regardless of whether or not they would be tested in the test. I focused too much on the test and not on the learning itself.

I also realised that i am very careless in the test. Of all my mistakes during the test, most if not all of them were because i was careless during my test. when i saw them, I thought " why did i put that? i knew the answer yet i wrote something else". i need to be more careful durign my test and check my answers again and look out for errors in my test.