Week of 2/22/10

This week, we learned about heat transfer. There are three types of heat transfer: conduction, convection, and radiation. Conduction is when heat molecules vibrate to heat other molecules. In convection, heat rises, then cools down, then goes up again. Convection is a flow of matter. It occurs in our oceans, our atmosphere, adn Earth's mantle. Radiation is when the sun gives us heat in rays. There are endothermic reactions and exothermic reactions. In endothermic reactions, heat is absorbed, so heat is a reactant. In exothermic reactions, heat is released so heat is a product. We learned how to calculate heat energy. Q= mc (deltaT) Heat energy is measured in calories or Joules. M is the mass measured in grams. C is the specific heat of the substance (cal/g degrees C or J/g degrees C). Delta T is the change in temperature (degrees C) = T final minus T initial. the equation Q=mc (delta T) describes the heating or cooling of a specific physical object. Each variable must refer to that specific object.

Week of 2/15/10

Last week, we had a test on reactions and stoichiometry. I understand reactions and I know how to do stoichiometry problems. I did not need to use my compostition book to take my test. We did a lab. We mixed 3M of hydrochloric acid and and 3g of sodium carbonate. We boiled this solution and salt was left in the beaker. We had a very small percent error. I think my balance was not a zero before I found the mass of the items. My group's balance was different from the other groups. There was some popping noise when the water was all boiled out and dry. Some white stuff came out of the beaker. I thought the popping noise was interesting.

Week of 2/7/10

In chemistry, we learned about stoichiometry. At first, it seemed complex. Later, I got used to conversion factors. I could solve prblems easily because I used the same format every time. I only used different numbers and substance. We did a lab about the oxidation of magnesium. For the pre-lab, we used stociometry to figure out how much magnesium we would need to use for th combustion. Our experimental error was about 5.56%. I thought that was pretty close. We formed Magnesium oxide from oxgyen and magnesium. While the magnesium burned, I thought it looked pretty cool because the metal was glowing a brigth orange color. The product was in the form of white powder. Next week, we have the stoichiometry test.

2/11/10

This weekend is going to be Chinese New Year and Presidents Day. I can't wait till Chinese New Year because of all the good food that I will be able to eat. This year, I can go buy flowers for Chinese New Year. During the previous years, I was unable to go to the flower shop, so I never experienced it. During the previous years, I always got sick and could not make it. I think one year I had a swim meet or something. This weekend I think I will have a lot of homework to do. I can't decide if I want to go swimming on Saturday. I feel lazy, but I want to improve. It will be a very busy weekend for me, but I hope I will have a great time. I know the weekend will fly by very quickly because of all the events that are happening.

Weekend of 2/6/10 and 2/7/10

We had a three day weekend because we had Friday off. We got to sleep in. On Saturday and Sunday, I had a swim meet. It was at my home pool. It was a distance meet. I swam the 200 breast and 200 back. I was in a relay race with two eleven year olds and a fourteen year old. I was the oldest one, but I was about the same height as the eleven years old. I had to do the 100 butterfly. It was so hard. Also, I made my team lose because of the fly. I slowed down my whole team ): For my 200 Breast, I made JO time, so happy! I was satisfied with my 200 Back time because it was my first time anyway. I got an A time.