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Water…. What are the Properties of Water?. How do bugs walk on water?. What is happening?. How does a paper towel “slurp up” liquid?. Why the curve?. What is weird about water?. Do you know how magnets work? Opposite magnets attract each Water acts like a magnet…
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What is happening? • How does a paper towel “slurp up” liquid?
What is weird about water? Do you know how magnets work? Opposite magnets attract each Water acts like a magnet… Water has opposite charges at opposite ends This is called Polarity
Water molecules act like magnetsPolarity causes: Cohesion & Adhesion & Surface Tension
Cohesion • Attraction between particles of the same substance (why water is attracted to itself) • Think “co-operate” (work together) • Results in Surface tension • Produces a surface “film” on water that allows insects to walk on the surface of water
Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND
Surface Tension • The “membrane” at the surface of the water is called “Surface Tension”
Bugs and more! - Cohesion • Jesus Christ Lizard and this too!
Water acts like a magnet • Water molecules have a positively charged side and a negatively charged side • When molecules come together, they stick like metal to a magnet
Adhesion • Attraction between particles of water and other substances • Think “adhesive tape” (sticks to other stuff) • Results in water droplets sticking to things despite gravity • Results in Capillary Action • Water “climbing” against gravity • Produces a curved surface called a Meniscus • Water molecules are attracted to the molecules in a graduated cylinder
Adhesion Causes Capillary Action Adhesion gives water the ability to “climb” structures... That's how the paper towel seems to “slurp-up” liquids!
Adhesion Also Causes Water to … Attach to a silken spider web Form spheres & hold onto plant leaves
High Specific Heat • Water is able to absorb a lot of heat before it gets hot enough to boil
High Heat of Vaporization • What is vaporization? • Water requires a lot of energy to change a molecule of liquid water into a molecule of water vapor (gas)
Less Dense as a Solid • Why do ice cubes float on water? • In liquids and gases, the molecules are moving... • When frozen, water molecules are “locked” in place... and the polarity causes water to attract and repel at the same time!
When water freezes... Ice actually has a very different structure than liquid water The molecules align themselves in a regular lattice pattern with “air pockets” between the molecules So, liquid water is more dense than frozen! Which is why ice floats on water!