Wonders of water day 2 and 3

Friday we had our daily question quiz and then started into more water labs.

First you filled your jars ALL the way to the top with water

Then you added enough water so that the level was slightly higher
than the rim of the jar.

Then we started adding pennies!!

One at a time you added pennies to your already full jar of water to see how many you could get in there before it overflowed.

Many of you were able to get quite a few pennies in there before it started to actually over flow!!!

Now to see what all of this means... we started into how water binds with other water molecules.

 

Using the models in your cups – make 5 water molecules then place how you think one would bond with 4 others.

 

What type of bond holds two water molecules together?
Hydrogen Bonds
 

Today we continued with notes and activities on Water.  First refreshing our knowledge of the structure of water and how it bonds with others using two slides from Friday (See above).  Then we moved on into Cohesion.

 

 
Next demo was to show cohesion and surface tension using pennies.


Using a Pipette, we added as many drops of water onto our pennies until it overflowed.  This was to show a couple things, first was Cohesion which is waters attraction to other water molecules.  The second was to show surface tension.  Because water is in love with itself, it wants desperately to be bound to 4 other water molecules.  Those water molecules at the surface of water have to hold on extra tight to the molecules beside and below it that it develops a sort of "film" at the surface.



Eventually the pressure would be too much and it would overflow, but the water molecules still are holding on to each other!!!!

Next we looked at surface tension with a different demo.......

We balanced a pin on the side of
the jar, let go and saw if we could get the pin to
float on the water



If you look very carefully, you can see how the water slightly "dips" in at where the pin is laying.  This is showing the how the  hydrogen bonds will "bend" a bit, but it takes a while to break

 Finally you started into Adhesion as we finished up the class period.