Earth Hour 2012

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Let's do our share 

official video from earthhour.org

for the Earth, for us.

For the love of Eating: The Digestive System

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I did not major in biology but this one is my fave, I guess because I love to eat! Aside from that I was assigned to report this when I was in elementary (grade 5 or 6) and you know what I still remember every single word.

photo credit: teachpe.com

The digestive system starts with the food we take into our mouth. Food is then broken down to tiny pieces by chewing and salivary enzymes. Once it is small enough, it will pass through esophagus a long tube connected to the stomach by muscle contraction. At the stomach, the food is mixed with gastric acid and then travels to the small intestine. Here food is further digested with the help of bile, pancreatic and other digestive enzymes. On the inner surface of small intestine is called the villi where it absorbs the nutrients from the digested food and into the bloodstream. The remaining food will then be transferred to large intestine where the remaining liquid (mostly water) will be sucked out, while the solid will become feces stored in the rectum and discharged at the anus.

Imagine the tedious job our digestive system has to undergo just to process the food we eat. And we mostly eat junk foods or foods with not much nutritional content! What a waste! It all goes to waste or become feces.

Fats are not easily broken down therefore are stored as is and can be blamed for the bulges we have in our stomach, thighs, arms, etc

That’s why some recommends eating fruits and veggies since it is easier to digest with lots of nutrients. Others say it is better to eat unprocessed alternatives like brown rice, whole wheat products, etc. It will take longer time to process it making us feel full longer. I am confused too but I know that I have to be mindful of what I eat.

What’s the matter?

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Matter is anything that occupies space and has weight. It means everything!

Is air a matter? Yes it is, though you don’t see it but it occupies space and it has molecular mass of 29 g/mol. The air we breathe is composed of 21% Oxygen, 78% Nitrogen and 1% other gases.

Basically there are three states of matter and they are solid, liquid and gas. The other two are quite complex to understand and cannot occur in normal conditions, Plasma is the fourth one and Bose-Einstein condensate as the fifth state.

So let’s focus on Solid, Liquid and Gaseous states.

Solid has definite shape and volume. Examples are stone and steel.

Liquid has a definite volume but takes the shape of the container. Examples are water and oil.

Gas has neither definite volume nor a definite shape. Examples are oxygen and helium.

Some matters can exist not only on one state, a perfect example is water. Water is naturally in liquid state but once it is subjected to an increase in temperature can be converted to water vapor or when subjected to a decrease in temperature turn into ice.

from Chem4Kids

The change from one state to another, in water's case from ice to liquid, then from liquid to gas are called physical changes because it only changes the appearance but the composition will still be of water or H2O.