Monday, February 25, 2008

Co-op Week Three

I am so behind on my blogging again!!  I have let two weeks go by without putting co-op plans up and it's almost time for Week Six!  

Weather Unit - Lesson Three

1.  Review what we've learned so far (weather vs climate, water cycle)

2.  Ocean Currents - how do they affect weather?

  • we discussed how warm and cold currents are present in the oceans and how they can affect the weather and climates at coastlines especially, and the effects of sea and land breezes.

  • warm currents bring higher temperatures and more precipitation, while cold currents bring lower temperatures and a shorter growing season

  • ocean currents are driven by winds and affected by the Coriolis effect - we talked a little about how the water drains in a spiral in a sink or toilet as an example of how the Coriolis effect is seen in the oceans.

3.  To demonstrate deep-water currents, we set up a little experiment.  Deep slow-moving currents of cold water flow from the poles towards the equator.  The colder, denser water (because it is not saline) sinks near the poles and is replaced by warmer surface water that cools, desalinates, and in turn sinks as well.  We wrapped up a bunch of ice cubes in aluminum foil and set that at one end of a clear pan of warm water.  (Make sure to wait until the warm water is completely still before putting in the pack of ice - and make sure the ice is well-wrapped so it won't easily leak as it melts)  We waited until the water was completely still after putting in the pack of ice, then I dripped some red food coloring on the aluminum foil, so it would run down into the water.  Then we observed what happened.

The colored water slowly drifted straight across the bottom of the pan away from the ice.  This is what happens in the oceans as well.  As the deep cold current nears the equator, it warms and starts to rise.  Each of the kids received a handout showing the major warm and cold currents in the world's oceans.

4.  We talked about El Nino and how it works. I did have a handout to give them as well, but I don't know where the link is for that.


CrossView said...

Looks like a great study! =D

Post a Comment

I love comments! It's like visiting over a virtual cup of coffee.