Thursday, 7 November 2013

Wind blows from high to low

This was our agenda for today:
Nov 6th and Nov 7th - Lesson 8
Content: Students will
Energy, light and heat
  • Explain how solar energy affects Earth’s atmosphere and surface (land and water).
    • light → heat
  • Describe the role atmosphere (e.g., clouds, ozone) plays in precipitation, reflecting and filtering light from the Sun, and trapping heat energy emitted from the Earth’s surface.
  • Explain how convection affects weather patterns and climate.
    • light → heat and onshore and offshore winds
    • reflection vs absorption
    • Explain the relationship between differential heating/ convection and the production of winds.
    • Analyze global patterns of atmospheric movements to explain effects on weather.
Today we did two investigations that have to do with heat and pressure:

The first experiment had to do with two jars with a paper bag on top of both of them.

  1. Try to pull the bag out of the jar.
  2. Try to push the bag out of the jar.
Here is a video and a picture:


We learned that..

Why doesn’t the bag come out of the jar?

As you pull the bag out, the pressure inside the jar becomes less.  The atmospheric pressure is higher, so it pushes the bag back into the jar

Why doesn’t the bag go into the jar?
When we push the bag into the jar, the air inside the jar becomes higher pressure.  The air inside the jar pushes out on the bag to the lower pressure atmosphere.
Than we did another experiment with a jar again. Than there was water and we lit the the top of the water on fire. We put the jar on top of the water

Here is a video:


We learned that...

Higher temperatures cause lower pressure.
Temperature is the average kinetic energy of particles, so if particles are moving faster, they spread apart and occupy less space.
So if the temperature increases, the pressure decreases.  
So the air inside the jar becomes lower pressure.  The air outside the jar is higher pressure and it pushes the water into the jar.

Than we watched a Brainpop video about Winds
We watched another video about Global Winds too help us even more
There is even a text to help you even more.

Mr. Pro did a diagram to help you more

If you are still confused the whole class drew a drawing :

This is what happens in Daytime at the beach:

This is what happens in the late evening at the beach:

A rhyme to help you remember is: Wind blows from high to low (pressure). 

Things we learned...

“What Causes Weather?

Where does most of the energy of the atmosphere come from?
It comes from solar energy (sunlight and UV rays).  
What happens to the solar energy in the atmosphere?
In the ozone layer, the UV rays are absorbed (changes to heat) so the upper stratosphere is hotter than the lower stratosphere.  
But most of the light goes through the ozone layer.
It could hit clouds or hit the surface of the earth.
If it hits clouds, the light will be absorbed or reflected.  Clouds tend to reflect light back into space.
If hits the surface of the earth, it hits either land or water.
icecaps: light is mostly reflected
brown/yellow: desert, grassland: light is both absorbed and reflected
green/grey/black: absorb a lot of light and reflect some (warm up)
absorbed and reflected, but water is special because it tends to stay a more constant temperature than land

Than the class had to answer questions in their task book. Here are the questions and answers:
High Pressure Regions:
Write down the weather associated with high pressure areas.
clear skies, sunny and dry
Low Pressure Regions:
Write down the weather associated with low pressure areas.
rain, cloudy skies

  1. What’s the relationship between temperature and pressure?
The higher the temperature, the lower the pressure (in an open system).  
  1. What’s the relationship between density and pressure?
If density is high, pressure tends to be high.  
  1. What causes wind?
Differences in pressure causes wind.  Winds blow from high to low (pressure).  
(Differences in pressure are usually caused by differential heating of the earth’s surface.)
  1. What causes differences in pressure?
Differential heating of the surface of the earth by sunlight causes difference in pressure.  Higher temperature air above hot land tends to be low pressure.  Cooler air tends to be higher pressure.  
  1. When light or UV rays hit something, what can happen to the light or UV rays?
They either reflect and/or absorb.  Lighter coloured things tend to reflect more light than they absorb.  Darker coloured things tend to absorb more light than they reflect.

1 comment:

  1. Sophia, overall, I think this post is perfect in information and videos, but you have a few spelling mistakes. The bag was made of plastic not paper, and we did not push the bag out we pushed it in. Also, check that you put the right *then instead of than. For the most part, great job!


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