Our first demo is trying to make wind more visible:
In one jar the bag is inside the jar. It was difficult to take the bag out because of air pressure. This happens because when we try to pull it out, air tries to go inside. In the jar there is low pressure and outside of the jar is high pressure. In the second jar the bag is outside and when we try to push it into the jar it is difficult. The same thing has the first jar, the air is trying to go from high pressure to low pressure..
The next demo:
In this demo we tried to figure out how heat affects air pressure. We lit up the alcohol burner and then we put the jar upside down, on top of the alcohol burner. If the pressure was higher inside the jar, it would push the water out. If the pressure was lower outside, it would try to get it and it would push the water.
In this experiment the flame went out because of the oxygen, but the amount of gas didn't change. What happened was that the water was pushed into the jar. It was pushed by air pressure.
Some fun fact:
- Higher temperature causes lower pressure
Let's imagine that the projector is the sun. The sun heats the planet, but, the heating up is not the same everywhere. This affects the wind because where higher temperature is lower the pressure.
After we talked about who we could apply it to the world. What makes the Earth's temperature change is the ozone layer that absorbs sunlight and heats up the Earth.
Then we looked at how the atmosphere changes, and they key was sunlight. The sunlight is absorbed or reflected, (more is absorbed in the equator, that is why it is hotter.) At the colder areas there is a higher pressure. Pressure moves from high to low. We saw that higher pressure has higher density and lower pressure has lower density.
Brainpop on Global Wind: http://www.brainpop.com/science/weather/wind/
Three facts I thought was interesting from the video:
- Wind is caused by the sun
- Energy goes through the atmosphere, and that energy is transferred to the ground, and the ground eats up the air above it. As it heats up it tends to raise. The atmosphere does not absorb it
- The world is connected through the atmosphere. We depend on atmosphere to breath. Now humans are ruining the atmosphere
Last class we talked about the ozone layer. Mr. Pro reminder us that the ozone layer is important because it absorbs the UV rays. When they touch you they cause sun burns and skin cancer.
Scientist makes climate graphs to tell weathers in different areas. In São Paulo in November, December and in January it rains a lot and is super hot. In June and July it is cold and it doesn't rain.
Question: Why when temperature drops, rain drops?
- Next unit is water
- Next class is review and on Wednesday is test