DO NOW
• HOW DO WE USE WATER IN OUR EVERY DAY LIVES?
• WHY IS WATER ESSENTIAL TO LIFE?
• PLEASE TURN IN YOUR OUTLINE IN THE BIN ON MY DESK.
OBJECTIVES
• TO OBSERVE THE DIFFERENT PROPERTIES OF WATER AND ATTEMPT TO EXPLAIN WHY AND
HOW THESE PROPERTIES OCCUR.
WATER PROPERTIES LAB
• GET WITH YOUR ASSIGNED LAB PARTNER.
• FOLLOW THE DIRECTIONS CAREFULLY FOR EACH PART OF THE LAB. BE SURE TO ANSWER ALL
QUESTIONS.
• THE COMPLETED LAB WILL BE DUE NEXT LAB DAY AND YOU WILL ALSO HAVE A SHORT QUIZ
ON THE LAB.
• *YOU WILL HAVE A SHORT SAFETY QUIZ TOMORROW AT THE START OF CLASS.
DO NOW
• WHAT IS THE CHEMICAL FORMULA FOR WATER?
• WHAT DOES A MOLECULE OF WATER LOOK LIKE?
• WHAT ARE SOME OF THE PROPERTIES OF WATER?
OBJECTIVES
• TO IDENTIFY WAYS IN WHICH THE STRUCTURE OF WATER
CONTRIBUTES TO ITS FUNCTION.
• TO EXPLAIN THE VARIOUS PROPERTIES OF WATER AND
GIVE EXAMPLES OF HOW THEY ARE SHOWN IN LIVING
THINGS.
WATER AND IT’S
PROPERTIES
2.1- 2.18
LET’S REFRESH…
• EVERYTHING AROUND US IS MADE UP OF ATOMS OF DIFFERENT ELEMENTS.
• ATOMS CONSIST OF 3 SUBATOMIC PARTICLES
• PROTONS +
• NEUTRONS
• ELECTRONS -
• THE ELECTRON ARRANGEMENT OF AN ATOM DETERMINES IT’S CHEMICAL PROPERTIES
• ATOMS OF DIFFERENT ELEMENTS BONDED TOGETHER CAN FORM COMPOUNDS
• EX: H20, NACL
THE WATER MOLECULE
• CHEMICAL FORMULA= H2O
• WHAT DOES IT LOOK LIKE?
H
H
O
THE WATER MOLECULE
• HYDROGEN AND OXYGEN ARE COVALENTLY
BONDED AND SHARE THEIR OUTER ELECTRONS.
• 2 ATOMS THAT SHARE ELECTRONS EQUALLY ARE
SAID TO BE NONPOLAR.
• CERTAIN ELEMENTS HAVE A BIGGER “PULL”
(HIGHER ELECTRONEGATIVITY) ON ELECTRONS
AND CAUSE AN UNEQUAL SHARING OF THE
ELECTRONS MAKING THEM POLAR.
HYDROGEN BONDS
• DUE TO THE PARTIAL +CHARGE OF THE
HYDROGEN ATOMS, WATER IS ABLE TO
HYDROGEN BOND TO OTHER ATOMS
THAT ARE SLIGHTLY NEGATIVE, LIKE
ITSELF.
• HYDROGEN BONDS ARE WEAK BUT VERY
IMPORTANT!
SO HOW IS THIS POSSIBLE?
THE DROP…
• COHESION: CAUSES WATER TO FORM DROPS
• SURFACE TENSION: CAUSES THE DROP TO BE SPHERICAL
• ADHESION: KEEPS THE DROP ON THE LEAF
COHESION
• WATER MOLECULES ARE ABLE TO “STICK” TO
EACH OTHER
• THIS PROPERTY HELPS PLANTS TRANSPORT
WATER.
ADHESION
• A SUBSTANCE’S ABILITY TO ADHERE OR
“CLING” TO ANOTHER SUBSTANCE.
• ADHESION OF WATER TO THE WALLS OF THE
PLANT’S VEINS HELP COUNTER GRAVITY!
ADHESION
• WHY DID THE WATER DRIP RIGHT OFF THE WAX PAPER?
ADHESION
• WATER IS POLAR AND WILL ONLY ADHERE TO OTHER POLAR MOLECULES.
• WAX PAPER IS NONPOLAR SO IT DOESN’T “STICK” TO IT. IF YOU PUT A NONPOLAR
SUBSTANCE ON IT LIKE VEGETABLE OIL, IT WILL STICK!
ADHESION +COHESION
• THE PROPERTIES OF BOTH ADHESION AND COHESION GIVE US CAPILLARY ACTION.
• WATER “CLIMBS UP” THE SIDES OF TUBES BY ADHESION AND COHESION PULLS ALONG THE REST OF
THE MOLECULES.
CAPILLARY ACTION
• TEARS ARE PRODUCED CONSTANTLY
TO PROTECT YOUR EYE BUT YOU ARE
NOT ALWAYS CRYING AND
EXPELLING THESE TEARS (YOUR EYES
WATER ALL OF THE TIME WITHOUT
DROPPING TEARS DOWN YOUR
CHEEK!). BASED ON THE PICTURE TO
THE LEFT, EXPLAIN HOW THIS IS
POSSIBLE?
SURFACE TENSION
• HYDROGEN BONDS GIVE WATER A HIGH SURFACE TENSION. (MEASURE OF HOW DIFFICULT IT
IS TO STRETCH OR BREAK THE SURFACE OF A LIQUID).
SURFACE TENSION
• WHAT DID THE SOAP DO TO THE WATER ON THE PENNY?
• WHAT CAN YOU CONCLUDE ABOUT THE MOLECULAR STRUCTURE OF THE SOAP?
• WHY DO WE USE SOAP AND WATER TO CLEAN THINGS?
EXIT SLIP
• WHY DOES THE WATER DROPLET TO THE
RIGHT GROW BEFORE DROPPING INTO
THE GRASS? WHY DOESN’T IT JUST ROLL
OFF OF THE LEAF? EXPLAIN USING ALL OF
THE TERMS WE HAVE JUST GONE OVER.
DO NOW