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Warm Up, October 24 th , 2013. Why does water stick to itself? Why does water stick to most other things? What do you think the term ‘surface tension’ means (as it relates to water)? Write the molecular formula for water and draw a water molecule.
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Warm Up, October 24th, 2013 • Why does water stick to itself? Why does water stick to most other things? • What do you think the term ‘surface tension’ means (as it relates to water)? • Write the molecular formula for water and draw a water molecule. • Why is water special (other than ‘it supports life’)
Pre-Assessment – Water 2 Then Graphing old Pre and Post Water 1
The Strange and Wonderful Mr. Water Water is an interesting, very unique, and required material in your every day life. But what makes water so great, you ask?
The Strange and Wonderful Mr. Water • It DISSOLVES most stuff…eventually —UNIVERSAL SOLVENT
The Strange and Wonderful Mr. Water • It DISSOLVES most stuff…eventually —UNIVERSAL SOLVENT • It occurs NATURALLY in ALL 3 STATES of matter. liquid gas SOLID
The Strange and Wonderful Mr. Water • It DISSOLVES most stuff…eventually —UNIVERSAL SOLVENT • It occurs NATURALLY in ALL 3 STATES of matter. • It’s NECESSARY for LIFE!
The Strange and Wonderful Mr. Water It’s NECESSARY for LIFE!
The Strange and Wonderful Mr. Water • It DISSOLVES most stuff…eventually —UNIVERSAL SOLVENT • It occurs NATURALLY in ALL 3 STATES of matter. • It’s NECESSARY for LIFE! • Its SOLID form (ice) is LESS DENSE than its LIQUID form. Why? Yeah I know that, but why?
Short Chemistry Detour So here’s a standard water molecule H H O Whose molecular formula is H2O
Short Chemistry Detour This same water molecule had a positive side and a negative side. H H O
And if you remember anything from 6th or 7th grade…it should be magnets.
Short Chemistry Detour So based on that knowledge, how is water molecule 1 going to react to water molecule 2? 1 2
Short Chemistry Detour The negative end is going to attract the positive end and vice versa. THEY ACT LIKE TINY MAGNETS. 1 Because of this, we say water has polarity. 2
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. ADHESION COHESION Adhesion, from adhere, verb - meaning: ‘stick fast to (a surface or substance).’ Cohesion, containing prefix co, - meaning: ‘together or jointly’
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. ADHESION COHESION Water will stick to other stuff and defy gravity. Water will also stick to itself! (polarity)
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. ADHESION Water will stick to other stuff and defy gravity. Example? Capillary action in plants!
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. COHESION Water will also stick to itself! (polarity) Think people cooperating!
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. COHESION Water will also stick to itself! (polarity) Also think, surface tension!
Short Chemistry Detour Now, because water molecules act like tiny magnets, very unique situations occur. Do you even lift? This random bug can balance on water, can you do the same with an ordinary staple?
Short Chemistry Detour So when water freezes, what happens and why does water expand???