In Class today, we covered the basic principles of water and its special characteristics by reviewing objectives 8-11.
Objectives:
8.) covered in last post
9.) Cohesion- ability to bond with other water molecules, Adhesion- ability to bond with other things
10.) The concepts we had to explain:
-why coastal areas have milder climates than inland areas
Because water has a high heat capacity it takes a while to heat up and the gas in the air does not have a very high heat capacity and heats up easily
-why ocean temperatures fluctuate much less than air temperatures on land
Because water takes longer to heat up and air is a gas which doesn't take long to heat up. (same idea as the last question)
-why water forms a convex surface above a glass
Because water has a bent shape; therefore, creating this convex shape over whatever container the water is in
-why water will travel up a paper towel
Because of adhesion and cohesion- water bonds together, forming a string of water molecules. Then those water molecules bond with the paper towel molecules and climb upward
-why ice floats
Because when ice freezes, it forms a crystalline shape that creates more space between the bonds. This also lowers the density.
- why humans sweat and dogs pant
Humans sweat because we need to cool off by releasing water outside of our body using sweat glands
Dogs pant because they need to cool off the blood in their tongues in order to cool off. To do so, the heat transfers from the blood to the water on the tongue, then the water evaporates, taking the heat with it.
- why a water strider can walk on water
Because its feet have little hairs on them, creating more surface area which allows it to walk on the water molecules
We also used pennies to observe the different properties of water. Here are some pictures and video:
We can see the convex shape here
This is how water responds to a toothpick and shows us the surface tension
This is a video of me testing out the surface tension with a toothpick that had some soap on it
This is a video of me testing out the surface tension
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