Gravitational force acting on your body at different places

Have you ever wondered what your weight is like on a different planet or place in earth?

This is what I am going to talk about today. Firstly, you need to know the difference between mass and weight. According to my Science teacher and some websites, weight is the amount of gravitational force acting on your body while mass is the amount of matter in your body. If you are on moon, your mass will be the same but your weight will change. That is because the amount of gravitational force on the moon is less that the earth. However, the amount of matter in you doesn't change so your mass will still be the same.

After looking at some interesting sites, I found out that we weigh heavier on the poles than on the equator. However, the difference is only less than 0.5%. If we are on mount everest, the force of gravity will be less. I couldn't find out why the force of gravity on mount everest is less but I think it is because we would be further away from the center of the earth. But, I did find out why we weigh heavier on the poles than on the equator. You weigh less at the equator because of a) greater distance from the center of gravity b) acceleration due to the rotation of the earth. The reason why you weigh more at either of the poles is because you are closer to the earth's center of gravity and there is no extreme rotation at the poles.

Using google to research, I found a fun website where you can type in your weight and get your weight on other planets. For example, if you weigh 40 kg on earth, you will weigh 15.1 kg on mercury, 36.2 kg on venus, 6.6kg on earth's moon and so on. This is the website: http://www.exploratorium.edu/ronh/weight/.

That is all. Bye.... :-) :0 :-D XD

Chilean Quake May Have Shortened Earth Days!

Chile earthquake

Earth's axis from outer space

This heading shocked me when I read this in the science daily on March 2.

Most of us know the chile earthquake that happened on the 27th of Feb 2010. It was an 8.8 magnitude earthquake. After reading this article, I found it quite interesting and so I decided to write a reflection again about this article as I did before in the post below.

Just to give you some information about the article: It talked about a research scientist Richard Gross. He computed how Earth's rotation should have changed as a result of the Chile Earthquake. After he used a complex model, he and his fellow scientists calculated that the quake should have shortened the length of an Earth day by 1.26 microseconds, which is a millionth of a second. Then, this article gave us another detail. It said that the quake should have shifted the Earth's axis by 8cm, which was more than the 2004 massive earthquake that shifted the Earth's axis by 7cm only.

After these details, the article told us the reasons why the Chile Earthquake shifted the Earth's axis more than the 2004 earthquake which was stronger. This is the url for the article: http://www.sciencedaily.com/releases/2010/03/100302084522.htm

After reading this article, I realised that earthquakes are very strong things. Before I even read this article, I did not even know that an earthquake could shift the earth's axis or shorten the length of each earth day. When they gave the explantion of why the 2004 earthquake did not shift the earth's axis as much as the chile earthquake even though it was weaker, I felt that science can also be a complicated thing. At the 2nd last line of the article, it said that Gross the scientist predicted that the chile's prediction of how much it shifted the earth's axis will change as data and the quake are further refined. Once I read this, I agreed because there is no real or confirmed answer in science. Just to give you an example: You cannot say that all living things need air. How would you know ? There could be a specie of an animal that has not been found yet and it may not need air the survive.

Written by: Ethan Teo

Warning: Those street sex drugs can kill

sildenafil
glibenclamide

I read this article a few days ago in the Straits Times and I decided to post some of my reflections about this article.

To give you a bit of background, I will tell you what the article talked about. It asked us to be beware of a kind of sex drugs that can be bought in the back lanes of red-light areas in Singapore. These sex drugs are already linked to ten men who died. According the the Health Sciences Authority, if these SEX DRUGS dont kill, they could still maim or leave a man with an erection so long that gangrene kicks in. It is very scary.

After reading this article, I felt that science is really an interesting and deadly thing. In those sex drugs, there are high levels of active ingredient in Viagra, glibenclamide ( a drug used to lower blood sugar levels in diabetics). Just because of these "ingredients" that made up the drugs, it lead to the deaths and injuries of people. Also because of these "ingredients", many people also fell into comas. This is why I feel science is deadly. Then, why do I feel that science is interesting? That is because there are many chemicals and drugs that can be quite interesting in terms of their uses. Some drugs may lead to problems with muscles and so on. Science is also part of our everyday life as I can see in this article.

These are some informations about the two ingredients that I researched on. The drug glibenclamide is an anti diabetic drug which was developed in 1966. This drug is used in the treatment of type ll diabetes. According to the straits times article, this drug is not even known to boast or help sex performance. The next ingredient is an active ingredient in viagra called sildenafil. The website I found said that it prevents the action of a chemical in the body called phosphodiesterase type 5.

Down here are some websites I used to find the information:

http://www.netdoctor.co.uk/medicines/100002749.html

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

Written by: Ethan Teo

Why and how did the density of water change when salt was added to it?

I think the density of the water changed when salt was added to it because salt has mass.

Density is equals to mass divide by volume. So if there is more mass, then density will increase.

Back to the experiment: So, when salt was added in, there was more mass in the glass beaker, making the density increase. Once density increases, things float. The tap water's density was lower than the eggs, so the egg floated. But, once salt was added in, the density increased, making the density of the water greater than the egg. Thus, the egg floated.

I went to this website too to find out more: http://www.reekoscience.com/Experiments/FloatEggInSaltwater.aspx :-D

Written by:Ethan Teo