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Why is PURE fresh water so hard to find on Earth?

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Presentation on theme: "Why is PURE fresh water so hard to find on Earth?"— Presentation transcript:

1 Why is PURE fresh water so hard to find on Earth?

2 Of ALL the water that covers 70-75% of our planet, 97% is salty & ONLY _?_ is FRESH.

3 Of ALL the water that covers 70-75% of our planet, 97% is salty & ONLY 3% is FRESH.

4 Most FRESH water is FROZEN, the rest is MOSTLY UNDERGROUND

5 And how much of this 3% is AVAILABLE for us to use?

6 Less than 1/3rd of our fresh water is available mostly from ________.

7 Less than 1/3rd of this tiny bit of FRESH WATER is AVAILABLE mostly from UNDERGROUND.

8 Why is there even less than that?

9 Some of that 1% gets mixed up with chemical pollution…

10 …and minerals like Calcium (Ca) & Magnesium (Mg) can make water TOO HARD.

11 But we COULD have more!

12 ICE is freshwater. Most of our freshwater on Earth is what: SOLID
LIQUID GAS

13 ICE is freshwater. Most of our freshwater on Earth is what:
SOLID ICE (is locked FAR AWAY at the POLES.)

14 and if the GLACIERS keep MELTING like LONNIE sees…
That fresh water just becomes part of the salty ocean

15 Precipitation is…

16 Precipitation is freshwater.
RAIN, SLEET, SNOW, HAIL…

17 but MOST precipitation falls in the OCEAN and thus turns…________.

18 but MOST precipitation falls in the OCEAN and thus turns…SALTY.

19 What are the atoms found in a MOLECULE of SALT?
Ca & Mg Na & Cl Na & F Ca & Cl

20 What are the atoms found in a MOLECULE of SALT?
Ca & Mg Na & Cl Na & F Ca & Cl

21 Why can't our H2O STAY FRESH!?

22 Why can't our H2O stay fresh?
I am troubled by this.

23 Think I’ll make a cup of soothing tea.

24 Tea dissolves. It’s a SOLUTE!

25 Things that dissolve are SOLUTES!
“solute” the tea bag!

26 Things that dissolve are SOLUTES!

27 Things that dissolve are SOLUTES!
“solute” the alka seltzer

28 Things that dissolve are SOLUTES!

29 Things that dissolve are SOLUTES!
“solute” the soggy cereal

30 Things that dissolve are SOLUTES!
“solute” the kool-aid!

31 Things that dissolve are SOLUTES!
Sugar’s molecular formula is C6H12O6 “solute” the sugar!

32 Things that dissolve are SOLUTES!
Salt (NaCl) dissolves too. “solute” the SALT!

33 Things that dissolve are SOLUTES!
tea sugar cereal salt (NaCl)

34 on the other side….

35 SOLVENTS are the liquids that do the DISSOLVING.

36 SOLUTE SOLVENT

37 The LIQUIDS & GASES that DO the DISSOLVING are SOLVENTS.

38 Identify the solute and solvents here…

39 SOLUTE SOLVENTS

40 Identify the solute and solvents here…

41 SOLUTE SOLVENTS

42 SOLUTE SOLVENTS

43 SOLUTE dissolve in SOLVENTS or SOLVENTS dissolve in SOLUTES?

44 SOLUTE dissolve in SOLVENTS or SOLVENTS dissolve in SOLUTES?
solutes like this greasy ceiling solvents like these cleaners

45 We can measure the amount of solute dissolved in a certain amount of solvent.

46 This “dissolvability” is called SOLUBILITY!
The more SOLUBLE a solute is, the more it dissolves in a certain solvent.

47 Identify the solvent & solute here:

48 Identify the solvent & solute here:

49 Identify the solvent & solute here:

50 After everything dissolves, it is called a SOLUTION.

51 After everything dissolves, it is called a SOLUTION.

52 dissolve in…

53 Solutes dissolve in…

54 Solutes dissolve in _______

55 Solutes dissolve in solvents

56 Which is a better SOLVENT? (which can dissolve more stuff?)
STRONG ACID FRESH WATER

57 Which is a better SOLVENT? (which can dissolve more stuff?)
STRONG ACID FRESH WATER yep! show cans, rusted parts, soup

58 WATER is the UNIVERSAL SOLVENT.

59 Water is the UNIVERSAL solvent.
Why?

60 NOT because it’s all over the place

61 NOT because it’s all over the place

62 WATER is the UNIVERSAL SOLVENT.
Let’s see why.

63 Every group gets a styrofoam cup.
Fill ½ cup with our UNIVERSAL SOLVENT

64 Choose your SOLUTE!! Put just a small bit in your UNIVERSAL SOLVENT Stir if necessary

65 Did your solute dissolve in the UNIVERSAL SOLVENT?
Who said “no?” DOES STIRRING HELP? WHY?

66 Now, turn up the HEAT! adding some hot water…BE CAREFUL!!!

67 WATER is the UNIVERSAL SOLVENT because it DISSOLVES almost EVERYTHING!

68 THAT’S our answer our EQ!
Why is it so hard to find PURE fresh water on Earth?

69 THAT’S our answer our EQ!
Why is it so hard to find PURE fresh water on Earth? WATER DISSOLVES almost EVERYTHING!

70

71 Why did SOLUBILITY (dissolvability) increase with a stirring & heat?

72 Write this CORRECT conclusion in your notes!
Stirring and heat increase/decrease solubility (dissolvabilty) because atoms & molecules lose/gain energy and move faster/slower.

73 Write this CORRECT conclusion in your notes!
Stirring and heat INCREASE solubility (dissolvabilty) because atoms & molecules gain energy and move FASTER.

74 clean up.

75

76 extension tiered graphing

77 How do temperature & solubility relate?
LET’S MAKE A GRAPH!!!!!

78 How do temperature & solubility relate?
Let’s check it out!

79 Solubility = dissolvability
100% S O L U B I T Y 50% 10% COLD COOL WARM HOT TEMPERATURE

80 Solubility = dissolvability
100% S O L U B I T Y 50% 10% COLD COOL WARM HOT TEMPERATURE

81 Water dissolves EVERYTHING.
Well, almost everything.

82 Because water dissolves almost everything, we say H2O is the UNIVERSAL SOLVENT.

83 Water is the UNIVERSAL SOLVENT because it dissolves almost anything.

84 Water is the UNIVERSAL SOLVENT because it dissolves almost anything.
Show some more examples…

85 Why is pure water so rare on Earth?
Because water dissolves almost everything it coats!

86 Most precipitation falls into our Ocean & gets salty!

87 Some gets mixed up with chemical pollution…


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