Water Properties

When my group and I experimented with the properties of water with the lab part B (wax paper) we learned and discovered something interesting. We discovered the drop of water didn't cut in half with a toothpick. It simply just slides across the paper where ever you move the toothpick. Why does this happen you may ask?...

--What is happening? Water is not attracted to wax paper (there is no adhesion between the drop and the wax paper). Each molecule in the water drop is attracted to the other water molecules in the drop. This causes the water to pull itself into a shape with the smallest amount of surface area, a sphere. All the water molecules on the surface of the sphere are 'holding' each other together or creating surface tension.

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We then moved on to the next project or experiment with part A (pennies). At first though it was crazy, like could multiple drops of water stay on a penny? I soon came to discover that YES its very possible even though we didn't get many drops of water we got quite a bit. These are the results we had;

Me: 38 drops

Taylor: 35 drops

James: 30

So now I wonder how can a little penny hold so many drops of water ?! Thats when I decided to find out how science or water properties make this happen...

 

--The reason the water stays on the penny is due to surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. Surface tension is like a flim that holds the water molecules together.

adhesion: The attractive force between molecules in one phase and different molecules in another phase.

 

Why does ice float?

--Ice simple floats because it is less dense then water. 

 

 

Important key words to know;

*cohesion: The attractive force between similar molecules in the same phase.
*hydrogen bond: A weak to moderate attractive force between a hydrogen atom bonded to oxygen, nitrogen, or fluorine, and an oxygen, nitrogen, or fluorine atom on another molecule.
*hydrophilic: Water-loving; a hydrophilic substance readily dissolves water.
*hydrophobic: Water fearing; a hydrophobic substance does not dissolve in water.
*polar covalent bond: Having an uneven distribution of electron density.
*solvent: A liquid which dissolves another substance without any change in its chemical composition.
*specific heat: The amount of heat needed to raise the temperature of a 1-gram sample of a substance by 1 degree Celsius.
*surface tension: The energy needed to increase the surface area of a liquid by a given amount.
*density: The ratio of a substance's mass to its volume.
*electronegativity: The tendency of an atom in a bond to attract shared bonding electrons.