Friday January 8, 2010 1.Objectives a.Students will understand three physical characteristics (polarity, surface tension, and molecular bonding) of water in order to understand how they influence the movement of energy in the hydrosphere. 2.Homework a.Moodle Pre-Assessment Test b.Moodle Lab Quiz c.Lab #1 Completion d.Print out the pre-lab worksheet for Monday 3.In-Class Activities a.Post –Lab Discussion b.How many water droplets can a penny hold?
Polarity Polar – A polar molecule is one that has opposite charges on opposite ends. Non-Polar – A non-polar molecule is one that does not have ends that are oppositely charged
Bonding Cohesive Bonding – Occurs between molecules that are the same. – In this case, the water molecules sticking to each other. Adhesive Bonding – Occurs between molecules that are different. – In this case, the bond between the plant and the water droplets
Surface Tension The cohesive bonding of water molecules that results from the polarity of the water molecule. Water has high a surface tension. – This is demonstrated as a drop of water falls from a spout. – The drop clings to the tap, stretches, and finally lets go – Check this out… Check this out…
How did we do? Our learning goal was to understand… – Polarity – Bonding – Surface tension The polarity of a water molecule leads to… …cohesive bonding…. …which means that water molecules form a sticky surface... …that will support things that should sink!