Avalanches and Ice Storms, and making freezing rain on a tile

One of the most interesting things we learned related to avalanches was about the invention of the "avalanche airbag." We did this demonstration with rice to show how lighter and bigger objects "float to the top" of an avalanche (it makes more sense to me to say that the smaller, denser objects sink to the bottom and push the bigger things up, but all our books described it as "floating," so maybe it is). These pictures don't really show what's going on here, but just put a bunch of toys and small objects into a jar full of rice and then shake the jar. The bigger things rise to the top and sit on top of the rice.

It's based on this principle that the avalanche airbags work. Here is one description, and here are a couple videos.

I think I mentioned earlier how I've never understood freezing rain and ice storms? Well, we learned that it's all about the right layers of air. We don't get them much here, but the pictures we've seen are so beautiful! Too bad they cause so much damage. 

Here's a good graphic explanation

Here's another diagram explaining the temperatures necessary for each type of precipitation.

One thing that's present in an ice storm is supercooled rain, which is basically rain that should be ice (it's at a temperature below 32 degrees F) but isn't, either because it has nothing to crystallize onto or because it hasn't had time to freeze. When this supercooled rain hits a cold surface, it freezes instantly onto the surface. We also learned about the types of ice, glaze (clear and smooth) and rime (bumpy and white because of tiny air pockets when it splashed up---it looks more like frost).

This demonstration uses supercooled water to make glaze on a ceramic tile. The instructions we had tried to make supercooled water by using distilled water (fewer dust/mineral particles in the water to provide a "hold" for ice crystallization) in a spray bottle and then removing the bottle from the fridge before it was totally frozen. We followed the instructions, but I'm not sure if our water actually became supercooled, or if it didn't but even water that is nearly supercooled works okay for this. Either way, it worked and it was cool!

To do this activity, you put a ceramic tile (or a smooth rock) into the freezer overnight. Pour distilled water into a spray bottle with the spray lid off. Let it sit, covered with a bit of saran wrap so dust doesn't get in, at room temperature for an hour or two. Then put the covered bottle in the freezer for another couple hours, until the edges are starting to freeze but the middle is still liquid. One of the times we did this, we let the bottle sit in the freezer too long and it froze all the way through. It worked fine to just let it sit on the counter for a little while, till it began to thaw, and then continue with the activity.

Insert the spray top into the liquid water in the bottle, and then remove your cold tile from the freezer and spray the water onto it. It should freeze into ice on the tile almost instantly!

The glaze formed by our "freezing rain"

You can see how we could slide this ice off in a thin, solid sheet. So interesting!

Wildfires and Lightning

Here are a few resources for wildfires and lightning:

In the past, we have had fun making "lightning" with balloons and light bulbs (as described here and here)

These videos here and here and here show a phenomenon called a pyronado or a fire tornado. We'd never heard of these before, but they are amazing! They are formed by convection currents, just like real tornadoes, but these currents are made by the fire itself rather by storm clouds. Really cool!

A video about volcanic lightning

Information on ball lightning (video quality here isn't that great, but we just don't have that many instances caught on video, I guess!)

The picture above is our little demonstration of how a firebreak works. You fill a pan with little pieces of crumpled-up toilet paper. Make a ditch in the middle. Then spray the toilet paper with food-colored water. You can watch the "fire" (red water) spread slowly through the toilet paper around it, but where there is no paper for it to spread through (the trench), it stops. This is the same way a firebreak (a ditch or other area cleared of trees and brush) stops a fire---if there is no fuel for it, the fire cannot spread.

Tsunamis (and other waves)

We quite enjoyed learning about tsunamis! Because of recent tsunamis in Japan and Thailand, there is a LOT of video footage of these huge waves. And as awful and terrifying as these events were/would be to experience, it is undeniably fascinating to see the pure power such enormous waves possess! Sam previewed the videos for us to make sure there was nothing too disturbing for the children to see. (In fact, if anything, they were a little TOO enthusiastic about the videos---I tried to impress upon them that real people are affected by these disasters, but it's hard to overlook the amazingness of those waves!) I said I hoped no one would have nightmares, and Malachi said it was going to give him goodmares. Hmm.

We did an activity to compare the origins of waves---regular waves, which are caused by wind, and tsunamis, caused by earthquakes. We got the idea for the tsunami-maker from this book.

You can find more resources on waves here.

To make your tsunami model, you cut out the bottoms of two nested foil pans (you could use just one, but two is more stable). Then cover the hole with duct tape. I can't remember what happened here---maybe we ran out of duct tape? You can see we used packing tape for the bottom side and duct tape for the top, so ours wasn't totally watertight.

Fill the pan with water, and proceed to experiment! First we set our pan down and blew on it with straws, making wind waves. We got some pretty big ones.

Then, we held the pan up and hit the flexible bottom part (the tape) from underneath to create tsunamis. You can really see a difference in the size and type of wave created by a disturbance under the water (an earthquake) rather than a disturbance above the water (wind). The earthquake waves are much taller and stronger because of the sheer amount of water they displace! We were inside the house (with towels) so I didn't allow the tsunamis to get TOO enormous, but I imagine you could do even more with this activity outside on a warm day! :)

Here are some of the tsunami videos we watched:

This video is a longer one that shows some of the footage from these other links. It's an entire program so it discusses how tsunamis form, etc. 

http://video.pbs.org/video/1863101157/

Some description of what caused it in this one

http://www.youtube.com/watch?v=foxww-tMoNg

The bigger wave comes in near the 5:00 mark

http://www.youtube.com/watch?v=IAa8BmuPqh8

This one gets interesting around the 4:30 mark

http://www.youtube.com/watch?v=I-KiGboUuy4

Newscast that shows some helicopter shots

http://www.youtube.com/watch?v=J2hUwFo6Vpc

http://www.youtube.com/watch?v=X3CleAc_iQ8

This is interesting because it shows what the waves look like before they get to land.

http://www.youtube.com/watch?v=-VcWF8dIDj4

http://www.youtube.com/watch?v=WRvcBBGIWio

http://www.youtube.com/watch?v=2rAJOo_VBhk

This one really shows the power of the water, but it does show some little kids screaming and crying about halfway through (they're safe, just scared)

http://www.youtube.com/watch?v=TRDpTEjumdo&list=RD2rAJOo_VBhk

http://www.youtube.com/watch?v=5-zfCBCq-8I&list=RD2rAJOo_VBhk

http://www.youtube.com/watch?v=vzvZy1zY8U8&list=RD2rAJOo_VBhk

Showing the aftermath

http://www.youtube.com/watch?v=MyTTrj4wKMU&list=RD2rAJOo_VBhk

Making a seismograph

I'm not totally sure I'm clear about the difference between a seismograph and a seismometer---I think seismograph is the older term, referring to a machine that actually outputs the data on paper (a seismogram). Now, they're usually called seismometers because they record the data digitally. If I've got that right, that would make our machine a seismograph. This was a fun project suggested in one of the books we read. It's easy to make---you just poke a hole in a paper cup so that a marker tip will fit through, like this:

You suspend the cup and marker from a string inside a box. Thread a long strip of paper through slits on either side of the box, and then gently shake the box as another person pulls the paper through.

Here is the seismogram our seismograph made! I think we recorded some large earthquakes. :)

Tornadoes, Hurricanes, Convection Currents, and Making a Barometer

You know you can't resist doing the ol' tornado-in-a-bottle activity! We did a couple variations on this. There are millions of resources for it online. We did the two-bottle version (two 2-liter bottles taped together at their mouths) and the jar version (like this), and I will say that I think adding the food coloring makes the tornado harder to see, so I advise against it. If you add glitter or other "debris," you can see things being pulled up by the vacuum in the center, which is kind of interesting.

I always wondered who on earth would buy these tornado tubes when you can just use tape---but our bottles leaked like crazy, so now I get it. If I were doing this repeatedly or with a whole class of students I'd invest in the tubes.

We've looked at water convection currents before, and air convection currents as well, but we did a quick review to precede our discussion on how tornadoes are formed. We also reviewed what we'd learned about vortices from our air vortex cannon. High- and low-pressure weather systems seem like they'd be simple to understand, and they ARE when you think in terms of air density and temperature, but I always have to talk myself very methodically through it to make sure I'm not mixing anything up.

Here's a good article about something that doesn't feel very intuitive---the fact that humid air (air with water in it) is actually lighter than air with less humidity. That means it doesn't push down as hard on the mercury or other fluid in your barometer, so the barometric pressure is lower. Again, this is easier if you actually picture a barometer. Lots of pushing from the air=barometer high, less pressure from the air=barometer low. Making our own barometer helped us keep this straight in our minds. It also helps me to think this: if the air is full of water, the actual air molecules have to be farther apart to fit the water between them, and therefore they exert less pressure on each other. More humidity=lower air pressure.

Here are two kinds of homemade barometers.

General idea for the water barometer here and the air barometer here. Our water barometer froze soon after this picture was taken, so I'd recommend the air one for colder weather! :)

Our friend Jena had the awful, but very interesting, experience of being IN a tornado! She was kind enough to send us some pictures, which were really fascinating to look at. There is something about seeing pictures from a real person instead of news reports---it makes the event seem so much more personal and real.

And here are some tornado pictures we liked from National Geographic.

Natural Disasters Unit Schedule and Lesson Plan

The children kept asking for a Natural Disasters Unit, but we'd already talked about several of these things (volcanoes in our volcano unit, floods and clouds and lightning and convection currents in our water unit, earthquakes and tsunamis in our rocks unit, etc) so I planned this unit to be a little less in-depth than it otherwise might have been. It's always fun to review things like volcanoes, though!

We also learned about several new things, one of the most interesting (to me) being ice storms and frozen rain---I've never understood why, if it's cold out, the "frozen rain" isn't just snow! Now I get it. We also made a barometer, which we've never done before and which we've found very fun to watch the past few weeks.

Natural History Museum

Sebby is SO HAPPY about this huge quartz crystal!

We went to the Natural History museum especially for their "special exhibit" on Natural Disasters, since we were about to start our Natural Disasters Unit. I'll try not to dwell with too much bitterness on the fact that the museum closed a half-hour before I thought they closed, so we got kicked out of the exhibit just as we were starting it by a zealous docent (although, as I pointed out to her, there were still 5 minutes left---"But we need everyone OUT by closing time," she replied implacably). As I said to Sam later, I've been kicked out of museums at closing time all over the world, so you think I'd be used to it by now, but I still get annoyed by that smug, not-my-problem attitude the docents always show as they sweep you toward the exit. It WAS my own fault for mis-remembering the closing time, as I thought I'd allotted plenty of time for the last exhibit. Still . . . what if a restaurant served you a lovely meal, then whisked it away mid-bite as the clock struck closing time? It was maddening.

Luckily (or not, I guess), the natural disasters exhibit wasn't that great anyway, as we saw while we were herded madly along through it to the exit. It was only a couple rooms, and had just a few rather basic "interactive" areas ("Feel this pumice!" "This slinky makes P-waves!") along with the usual tired Climate Change canards. So, no great loss.

The rest of the museum, which I had wisely (ahem) allotted most of our afternoon to, was great. We especially loved the minerals section, which had a great variety of specimens, many from Utah.

Erosion Table, always fun

Daisy making waves on the seismometer

Earthquake simulator (this "building" has cross-bracing and a tuned-mass damper on top to help stabilize it)

Beautiful topaz! We wish we'd found this!

Outside the museum

Leonardo Museum (the rest of it)

Here's what else was at the Leonardo Museum (besides the "Hylozoic Veil")---first, a room with screens and cameras set up to do stop-motion animation. You'd set up your pictures or your figures in a little room (or on the mat Seb is using above) and then push a button to take a picture, move your figures, take another picture, and so forth. You could press a different button to see your entire sequence when you were done. It was pretty fun, especially for the older boys, but it takes a loooong time to set up any sequence that tells a story or anything like that. Some people apparently have the patience for it, because there was a film reel playing in the room of sequences other people had animated with the same materials, and some of them were really good. But we got tired of it before creating anything too exciting.

Then there was a motion-capture room, where you stood in the middle of the floor and when you moved, a figure on the screen moved with you. It didn't work well, even for the big kids, and for the little kids it didn't work at all. Sam thought it might have been just an Xbox Kinect rather than the real motion capture setup they'd use for movies, etc. Maybe that's why it was so weak.

It didn't stop Daisy from enjoying jumping around in there, though. :)

There was a green screen you could stand in front of and a "weather broadcast" program playing in a loop on a screen, so you could pretend to be the weather forecaster. Fun, for a short time.

After that there was a room where you could use a touch-screen computer paint program. It was hard to use and the children have access to a better one (Sam's) at home so we didn't spend much time there.

Then there was the most fun part, which they called the "Tinkering Lab," where there was just a bunch of stuff out for the children to tinker with. Seb went right to the circuits. You could hook up lights or buzzers to circuits and switches and find ways to make them work. Seb really enjoyed doing that. There was a facilitator there who just let the children explore, but came out with gentle suggestions at just the right times ("Have you tried using two batteries?" "What happens if you attach it at both ends?") so nobody ever got too frustrated. She was awesome.

Ky and Abraham both worked hard building marble tracks on the pegboard. It took quite a lot of trial-and-error to get a result they were happy with! They had a lot of fun.

Honestly, if it hadn't been for this Tinkering Lab at the end, I would have thought the museum was pretty terrible. For our price (free with a pass we had) it was a fun afternoon, but for the regular price ($9 adults, $7 children) I wouldn't go again until they've beefed up their exhibits a bit. It would have been fun to see the Dead Sea Scrolls exhibit, but that seemed even more overpriced ($24 and $10) for only a couple of rooms full of stuff.

Shape-memory alloys, postmodernism, and the Leonardo Museum

We quite enjoyed learning about all the strange new materials invented in the last half-century, and the structures that these materials have enabled us to create. We watched some videos about strange, postmodern buildings that have fun breaking all the "rules" of architectural eras before them. We also saw some beautiful examples of Organic architecture (I love that house!).

One of the most interesting materials we learned about was something called Shape-Memory Alloy. Basically, it's a metal whose molecules arrange themselves into a crystalline structure at a certain temperature---and then, after being disarranged, they re-assemble themselves into the same structure when they return to that temperature. I'm not sure I explained that very well, but it becomes clear when demonstrated in this video. Amazing, right?

Here's something kind of cool you can do with SMA wire in paper.

Or bigger sculptures like this.

But for architecture, these materials have really interesting potential. They can be useful in modeling and CAD of unconventionally-shaped buildings, as shown here.

Or they could be used in the structure of the building itself, for example to open and close window shades when room temperature reaches a certain threshold, as demonstrated here. I know that materials touted as "materials of the future" don't always end up being as useful as predicted, but these are such interesting uses, I hope they do actually become integrated into architecture someday!

This brings us to our field trip, which was to the relatively new Leonardo Museum in SLC, to see a sculpture called the "Hylozoic Veil." It uses these SMAs to respond to the environment around it, providing a commentary on our shared and fragile humanity---or some such thing---fill in the art-jargon catchphrase yourself---but I thought it would be interesting to see, and it was. [I enjoy having a good laugh at the pretentiousness of the Art World, but I enjoy much Modern Art, with its sometimes-inane commentary, just the same. And it often does make me think. :)]

Because museum admission was free with our passes, we went into the museum as well, rather than just looking at the sculpture (which was in the lobby). It was pretty fun, though not worth the normal steep admission price, in my opinion (this seems to be a pattern for new museums around here, and I guess I understand it---open up a museum with not a ton of exhibits, try to get some word-of-mouth going, and expand as you go. I'm happy to have lots of museums to go to, so I don't mind patronizing them when they're new, but I can't help rolling my eyes a bit when I read their effusive ad copy, e.g. "The Leonardo seeks to reflect and respond to this new world by creating an innovative, dynamic space that builds fluency and knowledge, ignites the creative imagination of visitors of all ages, and inspires them to see and act in new and powerful ways." Hmm. Really?). I'll share pictures of the other exhibits in a different post. They have some of the Dead Sea Scrolls there too, which would have been cool to see, but that exhibit wasn't included with our admission so we didn't see it.

Nice rainbow lights in the entryway

More of the hylozoic veil---the beakers contain carbon dioxide so the thing actually exhales, or something like that.

It is really quite lacy and delicate looking. Beautiful.

We made mosaics in the "Art Lab" after going through the museum, and Malachi made his own depiction of the Hylozoic Veil. It's quite a good likeness, I think. :)

Building a Geodesic Dome

Geodesic Domes are cool. They were kind of claimed by hippies for awhile, but they're cool anyway. :) We loved learning about Buckminster Fuller and all his quirky ways (such as referring to downstairs as "instairs" and upstairs as "outstairs," to more accurately reflect our position in 3D space---awesome).

To understand geodesic domes, I first turned, as I often do, to my brother Karl. He told me what a "geodesic" is---it's the arc of a Great Circle that divides a sphere into hemispheres. But, I asked him, how is a geodesic dome made up of great circles when it looks like it's made of a bunch of triangles? He suggested I dip string in sugar water to make it stiff, and then wrap it around a balloon in several great circles. Then pop the balloon to see how it forms triangles when flattened.

Hmm. That didn't work. But we got the point anyway---the triangles form from the intersection of many great circles around a sphere!

We already know how strong triangles are, and when they are combined to approximate a sphere or hemisphere, they become stronger still! They are also lightweight and have the lowest ratio of building material to area covered of any structure. You can see why ol' Bucky (I'm not being disrespectful; he preferred to be called that!) liked them.

There's a really interesting discussion of perhaps the most famous geodesic dome (which looks like a geodesic sphere!), Spaceship Earth at Epcot Center in Disneyworld. The link includes pictures of the building process of that ride, which are fascinating to look at.

I have a soft spot in my heart for geodesic domes, as my dad loved them. When I was young he built us a huge geodesic dome in the backyard, out of lengths of pipe. We covered it with a tarp and it was the coolest playhouse ever. I'm not sure why we ever dismantled it. But it left a deep impression on me. So when I saw this plan for building our own geodesic dome, out of rolled newspapers, I jumped right on it.

I was pleasantly surprised at how easy this project was. You roll up a bunch of newspapers, cut them into two lengths, and then just attach them in a prescribed way. The hardest part for us was figuring out the intersections. We attached with tape, but our joints were sometimes unstable and there were weak spots. We had skimped a bit on the newspaper rolls (they say to roll three-thick, and some of ours were only two, and on the short side also) so the weaknesses may have been exacerbated by that. We are going to build another dome as soon as we have enough newspapers saved (my mom saves them, actually; we don't get the paper) and we'll try to be more precise and careful in our rolling.

The astounding thing, to me, was just how big the structure was. Just like one of those jungle-gyms we had at my elementary school playground! Except you couldn't hang from it, of course.

It was even more fun to play in once we covered it up with sheets. It was strong enough to support them, though heavier blankets seemed to stress it unduly, so we used our lightest sheets. Again, maybe it would have been better with thicker newspaper tubes.

Marigold was brought in to play more than once, much to her . . . dismay? I'm not sure what she was thinking.

A lot of giggling and crawling around in circles ensued.

So fun! We can't wait to do this project again.