Welcome to seventh grade science! This year we will be learning about life science, and with laboratory and scientific inquiry skills constantly in focus. I look forward to an exciting year!
It's tornado season! Tornadoes typically occur in Tornado Alley (Texas, Oklahoma, Kansas) during the spring and summer months. Warm humid air masses meet cold dry air masses, and sotrms form that often develop into tornadoes. Here is a video of a recent tornado that touched down in Oklahoma.
1. Winds occur because the earth is heated unequally. Warmer areas have low pressure and cooler areas have high pressure. Winds occur because air will always move from areas of high pressure (more dense)to low pressure (less dense).
2. We measure wind speed with an anemometer. We measure the direction the wind is coming from with an anemometer.
3. Local winds blow over short distances. Global winds blow over long distances.
4. Sea and land breeze occur due to unequal heating of the water and the land.
During the day, the land heats faster than the water. So, the high pressure cool air over the water blows to the land (low pressure) as a sea breeze.
At night, the land cools faster than the water. So, the high pressure cool air over he land blows to the water (low pressure) as a land breeze.
5. Global winds occur because the whole earth is not heated equally by the sun so pressure differences develop. Global winds curve due to the fact that the earth is rotation--this is called the Coriolis effect.
1. Temperature is the average energy of motion of a substance. Thermal energy is the total energy of motion of a substance. So even if a tea pot and a tea cup both have the same temperature, the larger amount of tea in the tea pot has a greater thermal energy.
2. Conduction does not heat the air well. Gases (air is a mixture of gases) do not conduct heat well.
3. The troposphere is heated when heat is transferred by radiation, conduction, and convection working together. First, heat is transferred from the sun to the earth by radiation. The ground absorbs this heat and then releases some of that heat by radiation and some by conduction. This heats only the air nearest to earth's surface. The convection currents occur when the heated air near earth's surface rises, and then cools and falls. The transfer of heat by convection is what heats most of the troposphere.
A magnitude 6.9 earthquake struck western China on April 14th. So far, the death toll is estimated to be about 600, and it is belived that 10,000 people may be injured. Many unstable buildings collapsed leaving people trapped under rubble. The area where the quake occurred is difficult to access, making rescue and aid more difficult.
Watch this video about the quake.
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