Thursday, April 26, 2012

Co-op Science Week 29

What can we explore that takes only one hour?  Because that's about all the time we have left for this school year.

Aha, Bernoulli effect.  It's an interesting idea, and we can mess around with some fun stuff.

After I explained what the Bernoulli effect was, we tried blowing over the top of crepe paper streamers to raise them up.  We also blew between 2 streamers to bring them closer together.

We made long, long tubes of plastic from Diaper Genie refills and blew them up with our breath.

We floated a ping pong ball on top of the flow from a hair dryer.  This was the most popular event, by the way.  You can tilt the hair dryer from side to side, and it looks like the ping pong ball is defying gravity.

We blew out a candle that was hidden on the other side of a tall can (I used a can of Trader Joe's Peppermint Hot Chocolate, a short candle, and an adult to be in charge of re-lighting the candle).

Then, continuing the theme of messing around with air, we made rockets out of Kool-Aid Burst bottles.  We had emptied out a bunch of these over the weekend thanks to a backstage workday for my kids' theater group.  I'd tried making a rocket at home using a regular straw for the inner straw, and a milkshake straw for the outer straw, but, alas, it was a dud -- the outer straw was too big.  I rummaged around and discovered that we had 2 boxes of regular straws, but one set was just a tiny bit greater diameter than the other -- it worked perfectly that way!  Add in the clay left over from last weeks clay boats, and we had rockets!

Except as the kids were experimenting one lamented, "I wish I could put fins on this, because I could do something really cool then...."  Aha, I had brought scrap paper, scissors, card stock and tape just for the occasion.

We had various competitions.  And at one point a firing squad.  Then some of the kids decided they preferred to simply blow on the inner straw.  I think that was the original design of this type of rocket -- I've seen it in older books written back before Kool-Aid Burst existed.

One class period left to go!

Wednesday, April 25, 2012

Work in Progress Wednesday

The white crocheted cords that were too white have been dumped in a pan of tea

and hung out to dry.  

So now they look appropriately dirty.  And ready to be used in knapsacks for Von Trapp children to use while fleeing over the alps.

In the meantime, capes have been cut out.  I just messed with this lining pattern until it became the actual cape pattern.  Also, I didn't pin down the pattern -- just used various canned goods

and cut out a stack of capes for the Von Trapp children.  From various fabrics, which I think are all polyester.

I'm going to serge around the edges to give them more finish.  And I need to come up with some kind of fastener.  The director suggested a snap, but I think that will pull off almost instantly, or else rip out.

Elsa's ball gown is done.  If I take out the basting on the bodice folds they all fall out, so they'll stay basted. I really like this dress -- can't wait to get a picture of it on.

I'll be glad when this show is over.

Saturday, April 21, 2012

Co-op Science Week 28

Density, part 2

We once again headed down to the kitchen to work on our investigations with density, using the activities from chapter 7 of Inquiry in Action 

After a review of last week's work,  the kids broke into 4 groups.  Each group had 2 clear cups of room temperature water.  They also received a little cold water which was tinted blue, and hot water tinted red.  They used eye droppers to put this in the cups of room temperature water, and noted where the colored water tended to float (note:  I supplied white cardstock to set under the cups to make it easier to see the colored water).  Overall, this is a tough activity for kids -- some of them don't have the coordination to gently squeeze water out of an eyedropper, and it's also hard to see where the colors are tending to float.  On the other hand, it's an easy activity to set up, inexpensive, and really does show that cold water sinks and warm water rises.  And then kids asked if they could drink the colored water, sigh, since we must have a big fuss about eating or drinking just about anything quasi-consumable in this class.

To finish off that concept, I did the ever-popular jars-of-water demo.  I once again used my glass jars from Frontera guacamole mix (at this point I've decided these are one of my favorite science tools -- easy to clean, easy to remove the labels).  This time I made the hot water yellow and the cold water blue.  Photos are from practice at home.  I put the hot water on top of the cold water first, using a playing card to hold the water in the jar (I tried an index card, but when index cards get wet they get sticky -- the playing card had a slicker coating on it).  As you can see, the colors stayed separate for a while

while I tipped the cold blue water on top of the yellow.  Which, of course, instantly mixed.
  And the big question was, "How do you get rid of it once you've got them stacked?"  You just grab them by the middle and take them over to the sink.
 I would suggest having towels on hand, though.

From there we progressed to the Diet Coke vs. regular Coke in a tub of water.  The Diet Coke floats because it's actually less dense.  Which worked just great at home BUT when I got to co-op I asked someone else to fill the tub I was using, a clear plastic file box, and leave it on the counter.  What I didn't realize is that she filled it with ice cold water.  Which, of course, was more dense.  So both Cokes  sank.  But, hey, we had just done a demo about hot vs. cold water, so hopefully the kids realized why it was sinking.  Frankly, they were mostly going on and on and on about wanting to drink the Coke.

Anyway, we forged ahead -- I asked how we could get the cans, particularly the regular Coke, to float. Someone suggested salting the water, which was a great idea.  But I had brought bubble wrap, which I stuck around the can.  I explained that we had increased the volume of the object without increasing the mass by much, and thereby changed the density -- sort of the same way life jackets worked.  Then I pulled out 4 clear plastic shoeboxes, which we filled half way with water, a bunch of plastic toys from home (insects, animals, and cars), along with some corks (I got those from the wine cork recycle bin at Whole Foods), some styrofoam (I couldn't find any packing peanuts at home that wouldn't melt in water, so I cut up a styrofoam box that we were throwing out -- this is extremely messy, by the way), some snack size zipper-style storage bags, tape, and rubber bands, and asked them to make "water wings" for their chosen objects.  They had a great time with this.

After we dried up from that, and collected some of the models to save, I brought up the idea that metal usually sinks in water but we have metal boats.  Our hands-on activity was using modeling clay to make a boat.  This involved handing out waxed paper for a work surface, and plenty of paper towels to blot up the water (when clay is wet it gets nasty to model).  Sometimes we just threw out the clay and started with fresh.  A couple of the kids were obsessed with needing to use waxed paper as part of their design to help waterproof the hull.

Some students did a great job with this, some couldn't get a floatable boat.  I was in the latter category.  I told them that there are mathematical equations to help with this, but we didn't delve into them.  Mostly I wanted them to get the idea that they could change the volume by shaping, and thereby change the density.

Overall, an incredibly messy lesson, but very satisfying.

I would high recommend the Inquiry in Action curriculum to anyone looking for ideas for a grade school science co-op.  For that matter, it would be outstanding to do at home with a single child.  Annabeth and I have discussed going through either this or the ACS middle school curriculum this summer here at home.  It's great stuff.

Wednesday, April 18, 2012

Work in Progress Wednesday

Simplicity 2252 en route to being Elsa Schraeder's ballgown.

As you can (maybe) see, we're adding straps to it.  Also, if I take out the basting on those midriff folds, they all fall out due to the extreme drape-ability of the satin , so that's a little awkward; I guess if I cared deeply I'd put some interfacing in it.  But, hey, it's only worn in one scene in a 2-performance musical, so not worth getting too excited about.

Still to come:  the bodice lining (we've decided to not bother with the boning -- again, it's not like it's a "real" dress) and some sort of hem (probably just narrow serging).  And, obviously, ironing, since hung up like this you can see all sorts of wrinkles.  And some sort of blob of tulle up at the neckline, like the movie version.

Overall, this is a fun pattern.

Wednesday, April 11, 2012

Work in Progress Wednesday

Seven knapsacks for the Von Trapp children to carry as they prepare to flee across the Alps.

 The director wanted them all out of burlap, but we only had enough burlap for 2 -- the lighter 2 in the middle -- thank goodness.  Burlap is really crappy to work with.  The rest are some weird textured knit that will never ravel or tear for the next several centuries.  The pattern is the same one we used for the Junior Girl Scout sewing badge.  The cords are crocheted from some yarn I found in the basement -- they're too bright white, but I plan to soak them in tea.

Also, the prototype for the cloaks the children will wear.

The pattern needs some more tweaking.  I'll serge around all the edges for a more finished look, and add some sort of fastener at the top front.  This one is out of some hideous knit.  I also have some pieces of wool, and some brown polyester.  The basis of the pattern was a free download from the Burda website. 

Elsa Schraeder's ball gown hasn't made much progress this week.  Oops.

Co-op Science Week 27

Density, part 1

I think the activities in Inquiry in Action for this subject are great, but absolutely dreaded carrying them out in a carpeted second floor classroom far from any sinks.  So my brilliant idea this week was to announce to the Co-op Powers That Be that we would be holding class in the kitchen.

The kitchen has a big island counter that all the kids could group around.  I started by discussing what happened when you skipped stones on a pond (the stone eventually sinks) versus what happens when you throw a stick on a pond (the stick, no matter the size, tends to float).  Why is that?  Some of the kids answered with confidence, "Because the wood has more air in it."  Which is pretty much on target.

I stuck a giant sticky note paper on the refrigerator door and wrote out that density is a function of volume and mass/weight (explaining as I went that I was going to be using the term "weight" instead of "mass" a lot of the time -- our in-home vote was that kids this age need to be aware of the difference, but we don't need to grind it down in this situation).

I filled a plastic container with water, and threw a stone in it.  Then I floated a block of wood on it.  I took both of them out and put them in a bucket balance to show that the wood was heavier than the rock.

Next we compared the density of the wood and rock to the density of water.  To accomplish this we used displacement to come up with a volume of water equivalent to the wood -- I filled a container to the brim with water, then pushed the wood down into the container, collecting the overflow in yet another container.  I poured the overflow water into a cup, which I set in the bucket balance to compare to the piece of wood.  The water was heavier, of course.  We repeated for the rock, although it was almost impossible to get a good displacement volume of water for the rock -- the surface tension of the water made it difficult to find the exact spot at which we could get a good displacement reading PLUS trying to get the rock-plus-container out of the outer overflow container without slopping water all over was pretty much impossible.  But I think the kids got the point of how it worked.  And could see that the rock was heavier than an equivalent-ish volume of water.

Bonus discussion while setting up and doing all of this -- Archimedes.  I asked if anyone remembered that story, and one of the kids did, although he'd apparently forgotten about Archimedes running naked down the street yelling "Eureka!" Or perhaps his parents had left that little gem out of the discussion -- who knows.

I passed out copies of worksheet 7.2 and we went over it verbally (some of these kids still blanch when they see a worksheet, afraid of ridicule).  We also cleared up the misconception that ice floats on water because it has air bubbles in it (in a way it's true, but not in the way that person was thinking).

Then, the ever-popular activity of pouring corn syrup, water, and oil into a cylinder, and seeing what happened.  I used the glass jars from Frontera guacomole mix, which were perfect for this.  Plus at our house we go through that stuff like it's water, so it was easy to collect several glass jars.  The kids worked in groups, figuring out the order in which they'd like to pour their liquids.  All liquids settled the same way, regardless.  Then we tossed in pieces of dry pasta -- spaghetti and macaroni -- pieces of popsicle stick, paper clips (which tended to whack into the pasta on the way down), and broken crayon.  I hadn't seen this variation of throwing in other random bits and seeing where they hovered in the liquids -- it's pretty fun.  We discussed relative density.  And, of course, several kids asked if they could drink the mix (they always ask that -- very predictable), and then someone asked if they could stir it up with the coffee stirrers that were on the counter.  Sure, why not stir it up and see what happens.

Finally, we filled cups halfway with water, then threw in pieces of carrot, which promptly sank (during which various kids asked if they could eat the carrots, sigh ... sheesh, this gets old fast).  We passed out small containers of salt and plastic spoons, and suggested trying to make the carrots float midway in the water.  While working on this we discussed floating in salt water, the ocean, and the Dead Sea.

Clean up was So. Much. Easier. because we were in the kitchen.  Again, I think this would've been a much more tedious lesson to plan in a classroom without a sink available.  But teaching in a room set up for this type of thing made it a fun, easy lesson in density.

Tuesday, April 10, 2012

Easter 2012

Good Friday -- Cantata at church.  Thalia was in it.  Some of it was good, some of it I tried to ignore.

Saturday -- decorating eggs.

"The Tardis is entering the time vortex."

Sunday morning -- church at 8am.  But we had to be there at 7:20 so Thalia could sing.  

Then home for the egg hunt,

 the Easter baskets,

goofing around in front of the camera

and trying to set the timer without laughing too hard.

Then over to the relative's house for Peep Cake,

playing ladder ball and also washers,

and general goofing around (that's the scarf that was in her Easter basket draped over bunny ears).

Friday, April 6, 2012

Co-op Science Week 26

Week 25 ended up not happening as a science class -- a couple of people wanted to test a 4th and 5th grade VBS curriculum they were writing, and asked if they could use one of our co-op's class periods for that.  Since science is the biggest group of 4th and 5th graders we had them use that class hour for their field testing.

On week 26, then, we took a look at states of matter.  I really diverged from the Inquiry in Action curriculum that we've been using this week.  Part of the reason was that I just couldn't face an hour of making condensation appear on glasses.  Another part was that Easter is approaching, so I decided to come up with a couple of Easter-centric demonstrations.

We began the class by discussing the states of matter, particularly solid, liquid, gas, and plasma.  I mentioned that there are lots of others such as Einstein-Bose condensate, but that by the time they would need to know those (say, college) there would probably be even more, so don't worry about them now.

We discussed how the molecules become more energized and further apart in solid, liquid, and gas.  I did the demonstration in the curriculum of using a glass of cold water and a glass of hot water to show the rate of mixing for a drop of food coloring -- the hot water molecules seemed to be moving around more quickly since the food coloring mixed in hot water much more quickly.

We also discussed how water moves from solid to liquid to gas (melting, evaporation) and from gas to liquid to solid (condensation, freezing).  I also explained sublimation and deposition, and gave example of each -- ice cube in the freezer becoming smaller, frost forming.  The kids then kept going off on tangents about dry ice, which is an excellent example of sublimation, but, yoohoo, IS NOT ICE MADE FROM WATER (so, for example, saying that the ice in your freezer was so cold that it was "dry ice" is incorrect ... unless your freezer is somehow putting carbon dioxide under enough pressure to liquify it and then freeze it.

Anyway, forward with the lesson, after yet more digressions to discuss ice on lakes in northern states (yes, you can drive on it).  To show how gas contracts when it cools, and also demonstrate a handy use for all of those hardboiled eggs leftover from dying Easter eggs, we did the ever popular egg in a bottle trick.  A couple of the kids had seen it before.  I used a glass bottle from Santa Cruz juice -- I'd taken in 2 bottles and 2 eggs in case we had a flop the first time.

And to show how gas expands when heated, what could be better than blowing up Peeps in the microwave?  This was accompanied by much discussion of the relative likability of Peeps, including some among us who've never tried them.  The leftover Peeps were handed out to those who wanted to eat one, which turned out to be a really small segment of the class.  By the way, although the church that hosts our co-op meetings has a couple of microwaves in their kitchen, I opted to take in a small, cheap microwave we have in the basement so I could use it in our classroom rather than trooping down to the kitchen.

Finally, thus far we'd been talking about changes in states of matter due to temperature change.  Matter also changes due to change in pressure.  As a reminder of the change in pressure, I also brought in everything needed to make Oobleck -- cornstarch and water.  Oobleck, of course, seems solid when pressure is applied, and liquid when it isn't under pressure. To make Oobleck for 14 kids without making a gigantic mess, I put a 1/2 cup of cornstarch in small ziploc-type bag2 (one for each child).  Each child then got a plastic cup and a plastic spoon.  I had water in plastic bottles.  The kids dumped their cornstarch into the plastic cup, and my assistant and I added about 3 tablespoons (plus a bit) of water to each cup.  The kids then stirred with spoons, and used their hands to mix it up.  We also had pitchers of water and paper towels on hand for clean ups.  And, most importantly, we had all gone outside before we started this particular adventure, so cleaning up spills consisted of dumping water on the sidewalk.

The entire lesson took less than our hour classtime, so the rest of the hour was spent enjoying the incredible weather -- sunny and in the 80s at the beginning of April.