Today, I completed the Air Pressure lab. I placed a plastic bag over the top of a jar and secured it with a rubber band to the top of the jar. I tried pushing the plastic bag into the jar but the air pressure in the bag made it difficult to do this. The air pressure inside the bag was higher than the air pressure on the outside of the bag. As I pushed down the plastic bag I felt the air pressure in the bag pushing back preventing me from pushing the plastic bag into the jar.
In the second part of the experiment, I put the plastic bag into the jar and secured it to the top of the jar with the rubber band. Then I tried to pull the plastic bag out of the jar. When the bag is inside the jar, the air pressure inside the bag is higher. Air pressure was pushing the bag down into the jar and there wasn’t enough air pressure between the bottom of the bag and the jar to allow the bag to be pulled up.
Sunday, April 18, 2010
Interactive Temperature Game
I played the Interactive Temperature Game. The purpose of the game was to match the temperatures of certain icons to their actual temperature. I was given the choice of playing the game using the Celsius, Fahrenheit or Kelvin temperature scales. On the Fahrenheit scale, water at sea level freezes at 32 degrees Fahrenheit and boils at 212 degrees Fahrenheit. The Fahrenheit scale is mainly used in the United States. On the Celsius scale, water at sea level freezes at 0 degrees Celsius and boils at 100 degrees Celsius. The Celsius scale is used by most other countries to report temperature. On the Kelvin scale, water freezes at 273.15 Kelvin and boils at 373.15 Kelvin. The Kelvin scale is the international standard for scientific measurement of temperature and is used mainly by scientists. When we measure temperature, we are measuring how fast the molecules or atoms, in a substance, are moving.
Green House Effect
Article Title: 2 More Glaciers Gone From National Park
The melting of glaciers around the world has accelerated in recent years. More than 90 percent of the worldwide glaciers are melting. Scientists believe increasing temperatures brought about by higher atmospheric concentrations of greenhouse gases are the cause of this melting. Glacier National Park is one of the places experiencing this accelerated melting. There were once 150 glaciers in Glacier National Park. A glacier needs to be 25 acres in order to receive a name. Thirty-seven of the glaciers in the park were large enough to be given names. Glacier National Park has recently lost two more named glaciers, Shepard Glacier and Miche Waburn Glacier, to melting. Of the 37 named glaciers only 25 remain. Geological evidence shows that these glaciers have existed for seven thousand years. Unfortunately, scientists predict that several of the park’s largest glaciers will disappear by 2020.
It’s sad to read that glaciers that have existed for thousand of years are melting away. In my opinion, the glaciers in Glacier National Park as well as the glaciers in the Himalayas, the Alps and all around the world will start to disappear due to global warming and the greenhouse effect. Studies have shown that an increase of greenhouse gases, such as carbon dioxide, in the atmosphere has caused the Earth’s temperature to rise at a faster rate than in the past. This temperature rise is melting the glaciers of the world. I hope this article will make people more aware of the effects of greenhouse gases and its effect on world’s glaciers. It is not too late to save the glaciers. Hopefully, people as well as the world governments will do something to decrease greenhouses gases so that the glaciers will not disappear.
The melting of glaciers around the world has accelerated in recent years. More than 90 percent of the worldwide glaciers are melting. Scientists believe increasing temperatures brought about by higher atmospheric concentrations of greenhouse gases are the cause of this melting. Glacier National Park is one of the places experiencing this accelerated melting. There were once 150 glaciers in Glacier National Park. A glacier needs to be 25 acres in order to receive a name. Thirty-seven of the glaciers in the park were large enough to be given names. Glacier National Park has recently lost two more named glaciers, Shepard Glacier and Miche Waburn Glacier, to melting. Of the 37 named glaciers only 25 remain. Geological evidence shows that these glaciers have existed for seven thousand years. Unfortunately, scientists predict that several of the park’s largest glaciers will disappear by 2020.
It’s sad to read that glaciers that have existed for thousand of years are melting away. In my opinion, the glaciers in Glacier National Park as well as the glaciers in the Himalayas, the Alps and all around the world will start to disappear due to global warming and the greenhouse effect. Studies have shown that an increase of greenhouse gases, such as carbon dioxide, in the atmosphere has caused the Earth’s temperature to rise at a faster rate than in the past. This temperature rise is melting the glaciers of the world. I hope this article will make people more aware of the effects of greenhouse gases and its effect on world’s glaciers. It is not too late to save the glaciers. Hopefully, people as well as the world governments will do something to decrease greenhouses gases so that the glaciers will not disappear.
Convection Popcorn Lab
Today, I completed the Convection Popcorn lab. My teacher used a popcorn popper to make popcorn. She placed the kernels in the popper. She turned on the popper. Hot air created by the popper transferred heat to the kernels, making the kernels expand and pop. There are three ways to heat something: conduction, convection and radiation. In this experiment, the popcorn was heated by convection. Convection heating occurs when heat is transferred by the movement of a gas or a liquid. In this lab, the movement of the hot air (a gas) transferred heat to the kernels. When heat was added to the kernels, the water in the kernel’s soft starchy insides turned to steam. The steam expanded so rapidly that it broke the hulls of the corn kernels and the starchy insides of the kernels expanded with air.
Layers of the Atmosphere
1. What is the basis for dividing the atmosphere into four layers?
The atmosphere can be divided into four layers based on temperature variations.
2. Does the temperature increase or decrease with altitude in the:
Troposphere - decreases
Stratosphere - increases
Mesosphere - decreases
Thermosphere – increases
3. What is the approximate height and temperature of the:
Tropopause - approximate height = 12 km, approximate temperature = -5 degrees Celsius
Stratopause - approximate height = 50 km, approximate temperature = -2 degrees Celsius
Mesopause - approximate height = 80 km, approximate temperature = -79 degrees Celsius
4. What causes the temperature to increase with height through the stratosphere and decrease with the height through the mesosphere?
Ozone absorbing ultraviolet radiation from the sun causes the temperature to increase with height in the stratosphere.
The mesosphere does not absorb solar heat, so the temperature decreases with height.
5. What causes the temperature to decrease with height in the troposphere?
The troposphere is heated by the transfer of energy from the surface of the Earth. The lowest part of the troposphere is the warmest and the temperature decreases with height.
The atmosphere can be divided into four layers based on temperature variations.
2. Does the temperature increase or decrease with altitude in the:
Troposphere - decreases
Stratosphere - increases
Mesosphere - decreases
Thermosphere – increases
3. What is the approximate height and temperature of the:
Tropopause - approximate height = 12 km, approximate temperature = -5 degrees Celsius
Stratopause - approximate height = 50 km, approximate temperature = -2 degrees Celsius
Mesopause - approximate height = 80 km, approximate temperature = -79 degrees Celsius
4. What causes the temperature to increase with height through the stratosphere and decrease with the height through the mesosphere?
Ozone absorbing ultraviolet radiation from the sun causes the temperature to increase with height in the stratosphere.
The mesosphere does not absorb solar heat, so the temperature decreases with height.
5. What causes the temperature to decrease with height in the troposphere?
The troposphere is heated by the transfer of energy from the surface of the Earth. The lowest part of the troposphere is the warmest and the temperature decreases with height.
Wednesday, April 7, 2010
Sunday, March 21, 2010
Frog Dissection
Well, we finally did it today. We got to dissect a frog. Not everyone has the guts to slice open a frog. Some queasy students just dread the thought of cutting open something that was alive. But what’s the big deal? We’re in science class. Aren’t we supposed to dissect animals in science class? Besides, the frog was dead already. I was kind of hesitant about dissecting a frog. I guess I was listening to all those queasy complainers. But it wasn’t as bad as I thought it would be. In fact, it was really interesting. There were four people in my group. We each took turns cutting out different parts of the frog. The first parts I saw were the liver and the fat bodies. Once I removed the liver, I saw the other organs such as the stomach, large intestine and the small intestine. I don’t think I need to list all the internal organs of a frog. I think most of you should know them. As for my group, during the dissection we were given permission to remove an eyeball from the frog. As we were trying to remove the eyeball, we learned an important lesson. Eyeballs are very delicate (because we popped it before we could get it out). During this dissection, I learned a lot. Since a frog is a vertebrate, I learned how a frog’s internal organs are similar to humans. I also learned that taking out a frog’s eyeball requires skill and a delicate hand.
In my opinion, dissection of frogs really helps you learn about the anatomy of the animal. Sure you can look at pictures and drawing, but seeing the real thing is much more interesting than pictures. I, like most students, learn best by seeing, touching and feeling objects. Dissecting a frog or any animal can be messy and gross, but they are very good learning experiences.
By:
greendragon
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