Kid Stuff: Water Labs 4.6-8

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Photos (top to bottom): photo1: Ethan using a plastic pipette to place drops of water on a 200 CFA coin; photo2: Alice, Emilie, Tori and Rosa; photo3: Ali creating a meniscus in a vial of water; photo 4, 18, 19: floating a paperclip on water's skin; photos 5, 8, 12, 15: water beading on the surface of a coin, a consequence of the cohesive properties of the sticky, polar water molecules; photos 6&13: soap weakens the hydrogen bonds between water molecules, and alcohol, a non-polar liquid, lacks cohesion and so does not bead; photo7: Luciana, Dalia & Goundo; photo9: Kosuke; photo10: Catherina; photos 11&14: Margret; photo16: Gabriel at floor-eye view; photo17: Aleah.

Five labs on surface tension (all common surface tension-related experiments widely documented on the web):

LAB1: Floating Paperclip/Needle

• Fill the bowl with water

• Try to make the paper clip float...not much luck, huh?

• Tear a piece of tissue paper about half the size of a CFA bill

• GENTLY drop the tissue flat onto the surface of the water

• GENTLY place a dry paper clip flat onto the tissue (try not to touch

the water or the tissue). Use the eraser end of the pencil to carefully

poke the tissue (not the paper clip) until the tissue sinks. With some

luck, the tissue will sink and leave the paper clip floating!

• Add a drop of liquid soap to the water. Observe what happens.

LAB2: Run-Away Pepper

Put water in your container. Sprinkle some pepper into the bowl until

you have an even layer of pepper floating on top of the water. Carefully squeeze a drop of liquid soap into the middle of the bowl. Observe and record what happens!

LAB3: Motorized Paper Fish

Needed materials:

• paper fish

• scissors

• liquid soap

• a large bowl or loaf cake pan full of water

Once you have your paper fish pattern cut out, place it on the water container so it floats on the surface. Put a drop of the oil or detergent in the hole in the middle of the fish.

The detergent or oil will cause the surface tension in that hole to drop. This will cause the fish to propel forward, leaving a trail of the oil as it moves across the water, not stopping until the oil has lowered the surface tension of the entire bowl.

LAB4: Over-The-Top

Fill a glass with water just past the rim without spilling. Place a soapy finger on the surface of the water. Can you guess what will happen?

LAB5: Knotty string

Knot a piece of string into a loop and allow it to float in a bowl of water. If you dip a match into the middle of the irregularly shaped loop, it immediately becomes circular.

The match has this magic power because it was previously dabbed with a little washing-up liquid. This spreads in all directions when the match is dipped into the water and penetrates between the water particles, which were held together like a skin by surface tension. This ‘water skin’ breaks in a flash from the place where the match is dipped in outwards. The liquid particles, which are made to move, push against the loop and make it rigid.

Kid Stuff: Exploring Probability 4.5

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Posted without commentary.

Weekend Dives 4.2-3

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Photos (top to bottom): photo1: frogfish (see frogfish); photo2: Aymeric takes defensive measures against the deadly, man-eating baby rockfish; photo3: nutibranch.

Wind-ing Down: Changes In The Air

Change is in the air, literally. The wind has stopped, it’s a little warmer, and a little more humid, or so it feels.

My large bath towel has not been drying in the 24 hours between morning swims. I’ve been turning on the classroom air conditioner just after lunch, the room beginning to warm up. The pool temperature has been rising, gradually. Clues.

The slowing of the wind is a mixed blessing. On the plus side, the sea will begin warming when the upwelling engine slows, which is driven by the prevailing off-shore winds. It is also a clear sign that spring has arrived and the school year cycle is gradually winding down. On the minus side, warmer weather means stickier weather.

Change is in the air.

I’ve begun collecting, sorting and packing my personal belongings in the classroom for transfer home, in preparation for shipping to Monterey in May. The skull set is wrapped and packaged in a hardshell suitcase, the same one that it arrived in three years ago. While I’m leaving a substantial number of ROV parts and electronics with Tom and Ali, the higher end components are headed home. At a glance, the classroom remains unchanged. Only a keen, inspecting eye would notice the rearrangement of boxes and newly available shelf space.

A Polar Molecule: Bending Water

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Photos (top to bottom): photo1: Mourtada; photo2: Brittany; photo3: Sheila; photo 4&5: Kosuke, Tori, Anais; photo6: Charne; photo7: Marietou, Devyani, Malick; photo8: Alphadi; photo9: Devyani; photo10: Bella; photo12: Catherina; photo13: Alice, Abel, Rosa, Tori, Anais; photo14: Rosa, Emilie, Tori, Anais.

What's happening around class?

We've begun a unit investigating the nature of water, opening with a look at its physical and chemical properties. Here the kids explore the polar nature of the water molecule, as demonstrated by our ability to bend it, or to use a charged object to attract the more positive side of the molecule.

Photos 12-15 show 6S playing two Everyday Math inspired math games, the first exploring probability, the second practicing finding solutions to simple equations.

Hit Me With Your Best Shot: Co-Habitating With a Boxer

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Chaussettes' back for a three-week stay, while Philippe joins Hilda in some exotic, South Pacific dive locale.

I had anticipated a honeymoon, when she'd cower under the bed, terrified by the sudden change of scene. Not so. She was on the prowl in minutes. Obviously, she has an excellent memory.

Some pets amuse themselves. Like kids, you can kind of wave them off, as if to say, go find something to do. Unfortunately, for Chaussettes, attacking me is that something to do.

For Chaussettes, a visit with Tod is an all-inclusion resort: food, lodging, and sports activities. Here's what's on the sports' agenda for today:

laptop hand batting

across the apartment ankle ambush

grooming

trash upturning bone search

laptop hiking

bug chase

arm wrestling (talons retracted, love bites)

napping

arm wrestling (talons not retracted, shark bites)

cuddling

toilet roll unraveling

Strange. It's quiet at the moment. Hmm. I'd better investigate . . .

I've shot some video in the past few days. Enjoy:

Meow1

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