A couple links that look very helpful.

100 excellent blogs for science teachers (which includes yours truly!)

Includes a bunch of teacher blogs (which seems like a great way to get some online mentorship if you’re all alone), and subject-area blogs (like physics or biology). A very useful list.

100 cheat sheets for K12 teachers

The sections on math and science include such helpful handouts as trig basics, basic principles of chemistry, how to add positive and negative numbers, from a variety of sources and websites (many from Clif Notes).

Here are a few collections of videos of science teaching and learning — useful for learning how to teach.

Annenberg:

http://www.learner.org/resources/series90.html

http://www.learner.org/resources/series126.html

TIMSS

http://nces.ed.gov/timss/video.asp

Ok, it probably wouldn’t be very yummy, but here’s another hands-on activity you can use that’s rather Halloween-like. Called “Make a ‘mummy’”, this Exploratorium activity is a great way to demonstrate how mummification works, by drying out the tissue in a fish using baking soda. Egyptians used a specific type of salt to do this, but baking soda will do the trick, giving you a tough leathery fish.

If you’d just left your fish out on a shelf, exposed to the air, bacteria and fungi would have begun to decay the fish, creating strong, unappetizing odors. Since all living things require water to survive, removing the water from the fish greatly inhibited the growth of these organisms, decreasing the unpleasant effects of rotting.

For an inquiry activity, try substituting salt for baking soda. Which one works best? (Hint: It’s not the salt).

Make him a little pyramid home. Imagine his little fishy afterlife. Bury some fishy mummy friends for him to play with.

Pyramid photo From Platonides on Flickr.

Originally posted on my sciencegeekgirl blog.

With halloween fast approaching, it’s time to take advantage of a frivolous holiday to do some fun science stuff.

No post about Halloween would be complete without a reference to the Grossology site. Scroll down for “lab activities”: This gets high marks from one teacher who says, “It has the simpliest of the slimey things, glue slime, and fake blood.”

In that vein, read the post on “how to make slime” over at Schooner of Science. The Schooner also has a recent post on zombies — an interesting story about the origin of zombies and a toxin-like powder which may, or may not, have put people into a zombie-like state.

The “whoosh bottle” is also somewhat spooky as a demonstration. And you get to talk about gas laws and combustion, too.

Fire is always fun. If you google Exploding Pumpkin Experiment or Flaming Pumpkin Experiment, you can find some great things to do with those leftover jack-o-lanterns after Halloween. Here is Steve Spangler’s version of an Exploding Pumpkin that carves itself. Most people just have the pumpkin shoot flame from its mouth. You can get lycopodium powder (from Flinn Scientific, for example), and use a syringe to spray it along candles at the bottom of a pumpkin’s mouth, creating a fireball coming out of the mouth. Obviously, t there are safety measures to consider. The video below has the best explanation of how to do this that I found.

And here are a few suggestions from veteran teacher Raleigh McElmore:

Slime: If you can score a magnetic stirring hot plate you can easily get Poly vinyl alcohol at a chemcial supply store and make up some great slime at 40 gr/L and mixing it with a bit of Sodium Borate (known as “Borax” and in many supermarkets detergent aisle) at 40 gr/L.

Your own grossology: In elementary school I always filled a big pyrex bowl with peeled grapes that had been soaked in red food coloring. This brings out the “veins” in the grapes and I announced that “eyeball soup” would be shared with the students. A chunk of dry ice, the grapes and fill the bowl with cheap fruit punch gives you a seething and bubbling drink with “eyeballs” floating around. Or you can, for realism, use sheep eyeballs. Give them to your star pupils. I’ll keep an eye out for you.

And to keep them on their toes:

A great magic trick that Penn and Teller invented is to bring two cans of sparkling soda (not anything else as this is messy). Give one can to a quiet student tell them to keep the can totally quiet. Give the other can to a hyperactive sort and tell them to “shake the can as hard as you can without touching anything”. Did I mention that this should be done outside, oh yeah, do it outside.

Take the highly shaken can, put it in plain sight and say that this is the season for strange things. Tell the students that you will change fizz in the shaken can to the quiet can. Gently touch the quiet can and touch the shaken can. Mumble incantations about AYP and other scary things. Waste at least 30 seconds in mindless babble and then take the “quiet can” and hold it high while you open it. Curve your fingers behind it and squeeze the can as you pop the lid. It will shoot fizz all over everybody as you have secretly crushed the can. After you have sprayed everyone dramatically throw the can into a nearby garbage can to avoid students seeing the crushed can.

Then quietly open the shaken can. The gas will have gone back into solution by then and it won’t do anything. Explain to the students that teachers are given these powers, but only to be used for the good. Drink the calm can and draw attention from the garbage can with the crushed evidence.

Need more ideas? Here are some links here and here and here.

Top image from Extremepumpkins.com

Originally posted on my sciencegeekgirl blog.

Got a unit on circular motion? You may want to use an activity with a centrifuge, to show how it separates substances of different densities. Even if you’ve got a commercial centrifuge, how might you instead do a hands-on activity to show the same thing?

Try mixing red colored sugar in cooking oil in a syringe (10 ml). You can use the holiday colored sugar, or dye your own with food coloring. Attach string to the syringe (very securely!) and swing it around your head. This simulates a hematocrit test, which measures blood count, and the mixture looks a little bit like real blood. The sugar represents the packed cells, and the oil is the color of plasma.

Thanks to Karen Kalumuck of the Exploratorium for this idea. If you want a copy of her write-up of the activity, write me (stephanie at sciencegeekgirl dot com).

Another low-tech centrifuge is a salad spinner, which you can get at any thrift shop. Separating vegetables from water is not quite a density-driven process, as the vegetables are large and the water is driven to the outside because of its fluidity. Though, you will find that carrots end up on the outside and lettuce on the inside.

Originally posted on my sciencegeekgirl blog

Have you ever had this unusual occurrence in your freezer? This one observant science teacher says:

We had a single stalagtite form from one cube in an ice cube tray. It rose about an inch, no more than an eighth of an inch in diameter, and tapering to a sharp point. How did that form?

Paul Doherty (physicist extraordinaire) answered that this is called an ice spike.

The water in an ice cube freezes from the outside in. Once the outside is sealed the water inside freezes and expands.
So the interior water is pressurized.
If it freezes at just the right rate the pressure can push the liquid water out of a hole in the top surface and freeze it.

It helps if the water is clean and free of nucleation sites i.e. distilled

See this website here for a bunch more information and great pictures.

Originally posted on my sciencegeekgirl blog.

Here’s a provocative question about the atmosphere, from one of those most curious citizens of the world — 6th graders.

“At sea level you take a breath and fill a sandwich bag with it easily. On Mt Everest, not using bottled air, could you do the same thing? I guess the question is “How full are your lungs at 28,000 feet?” If you filled a sandwich bag on top of Mount Whitney, would it still be full when you brought it back down?”

When you fill your lungs at high elevation, the air has the same volume, but it’s less dense. That means that there are fewer air molecules in a breath of air at 28,000 feet. So your lungs feel just as “full” but there is actually less mass of air there. So, the answer to the question depends on what you mean by “full.” The air pressure on Mt. Whitney is ½ the pressure at sea level. So, says Paul Doherty (my old mentor), it’s like someone ripped out one lung. You’re only getting half the oxygen as you are at sea level.

The same is true of the air in the sandwich bag – it’s less dense. But the air outside the sandwich bag is also less dense than it was at sea level. The bag fills easily because the air outside the bag exerts less pressure. If you blow up a balloon underwater, using pressurized air, the same thing should be true.

But then when you bring that sandwich bag down from Mt. Whitney, since it’s only got about ½ the air molecules in it that it would have if you had filled it at sea level, it looks a little deflated. It will have half its original volume. This is why your water bottle crinkles in on itself when your airplane lands.

Underwater, it’s the same story. You fill a sandwich bag with air at 100 feet. The air in your lungs is compressed to ¼ of its original volume. So you fill the sandwich bag with this compressed, dense air. As you come up, the air expands to 4 times its original volume. Says Paul Doherty,

Bang, it explodes.

And, adds Paul:

On a free dive your lungs don’t explode on the way back up. They just expand to their original volume. However if you took a breath from a scuba tank at 100 feet and then held your breath on the way up , DON’T DO THIS! your lungs would do what the sandwich bag did…not good.

This has killed many divers before.

Picture of Mt. Whitney from user Ziemusu on Wikimedia commons.

If you’re looking to beautify your classroom, here are some links to some free science posters. No guarantees as to quality, but these links should be a helpful start!

http://www.johnny-lin.com/posters.html#powersoften
http://www.tufts.edu/as/wright_center/products/svl/posters/posts.html
http://www.mii.org/teacherhelpers.php
http://www.surfnetkids.com/games/Science_Games/
http://www.scattercreek.com/~zimba/freeforteachers.htm#posters

Originally posted on my sciencegeekgirl blog.

We see the darndest questions on teacher listservs. It seems that, at one school, there was a mystery to be solved. The boys’ urinals were often surrounded by a puddle of “liquid.” Were the urinals weeping water? Or were the boys purposely urinating on the floor (as the janitor believed)? And, most importantly, how can we use our good friend SCIENCE to solve this mystery, the teacher asked?

Is there a powder I can sprinkle on the floor that will turn a particular color?
A UV light to shine on the puddles that will fluoresce?

It turns out that, yes, there is such a device! Specifically created to detect pet urine stains, the Rug Doctor is here to help (and so are a plethora of other products). It’s a blacklight, and it turns out that certain molecules in urine (just like in semen and blood) will fluoresce. They use this at crime scenes too. “Fluorescent” means that a material absorbs light of one color, and then re-emits it in another color. Blacklight is ultraviolet, which is highly energetic light that is “too blue” for us to see. The fluorescent molecules absorb that light, which loses some energy in the process, and re-emit it in as light that’s lower energy (that we can see).

I used to study some fluorescent polymers that fluoresced in room light. They were beautiful. The liquid in the little vial seemed to glow (well, it did glow), this kind of chartreuse. The picture here isn’t from my research, but similar material.

Here are some common materials that glow under blacklight.

Anyway. Back to the problem at hand. We weren’t quite sure how these blacklight devices would work for detecting urine in tile grout (which probably holds all kinds of things). And how would one know if you were detecting backsplatter, or intentional misbehavior?

One teacher helpfully added:

A couple solutions I’ve seen to encourage boys to aim properly- in a bathroom at a truck stop in Alaska, there were the normal plastic filter things over the drain, but they had a little propellor thing labeled “Restroom Roulette” If you directed the stream at it, it would spin around until you stopped and point at various things like “You’re a Winner!” or “Sorry, try again” etc. Most kids would get a kick out of that. I’ve also seen urinals where the realistic image of a fly or a spider is etched/painted onto the urinal at the “sweet spot” where you get the least splashes. Males apparently can’t resist trying to nail the bug to try to wash it down the drain.

“Visualized whirled pees?” responded one.

Other suggestions included:

You could change the school water supply to include small amounts of the super absorbent stuff (sodium acrylate?).

The simple remedy is to issue each boy a pair of vice grips set to clamp to a small circumference. This will restrict flow, encourage returning to class and giving new meaning toclamping down on a problem. (Raleigh McLemore)

I had hoped to avoid stepping into this subject out of fear it may be too deep for me.

Some things are too serious to joke about.

One of our more prolific contributors (Al Sefl) shared:

A classic book has been written about the trajectory of droplets caused by a liquid stream impinging on the urinal receptacle surfaces. I believe The Bathroom by Alexander Kira was the first and most comprehensive study of both male and female urinals with backsplatter patterns. It pointed out that most of the bathroom appliances were poorly designed and kept that way out of some misdirected sense of traditional design. … He came to the conclusion that the clear majority of receptacles were not scientifically designed to minimize splash droplets. Other conclusions included were that the height of male urinals were often above the stream source so the end of the stream, as it peter’s out so to speak, often drops below the lower edge of the urinal. The book was a text used in a course for one of my master’s degrees, Industrial Design. It was very obvious that a complete redesign of the western lavatory in general was needed.

Al Self

Who thinks urinals should have a sign posted over them stating:

MIND THE GAP

I was recently reminded of this wonderful visualization of the processes inside the cell. As a physicist, I found this quite powerful in imagining this mysterious (and usually, to me, boring) microscopic world. It was created by a Harvard professor in conjunction with a scientific animation company. Here’s the video:

In my art and science visualization seminar we had quite an energetic discussion about this video, however. There seemed to be a lot of skepticism in the room about this visualization. “It’s not art,” claimed the artists in the room, and the scientists (who were not biologists) were suspicious of its scientific content. I’m here thinking this is the greatest thing since sliced bread, and they’re tearing it apart. What gives? Are we distrustful of something that looks slick and expensive, as opposed to something homegrown? I haven’t seen such resistance to people’s aesthetic garage experiments. Perhaps because the garage experiments are simply celebrating aesthetics, not trying to convey scientific content.

One aspect of this video, of course, is its emotional content, which can serve to motivate people to learn biology. It uses different camera angles, an movement, and music, to make the viewer feel that they are zooming around these dynamic views of the inside of the cell. In terms of how people learn information cognitively, this is also useful. Multiple representations of a phenomenon are very useful in helping people make sense of information. Most science content is presented quite abstractly. As our guest speaker Martin Kemp said, this isn’t the science lesson, it’s the teaser.

Certainly, this video doesn’t stand on its own — it needs verbal support. Presumably an instructor would use it before or after instruction where the content is more explicitly explained.

There is an emotional narrative here, said the seminar participants. How does that relate to the intellectual narrative. Does this compromise the science? One claimed that there is incredible intentionality depicted here. The processes we see aren’t random, it’s very cooperative, like a small city. These little things are working very hard to accomplish what they do. They’re not self-conscious, but still are active agents.

This is dangerous, several people argued. We don’t know if these objects have intentionality. It turns out that the Discovery Institute co-opted part of this video to illustrate that God exists in the cell.

But, I argued against this. The “intentionality” that people saw in this video, I think, was their own anthropomorphizing. There was no intentionality inherent in the video — only motion. Any intentionality is just a metaphor, just like the “selfish gene” is just a metaphor. It can help us to imagine these ideas by ascribing intentionality, perhaps, but we need to be very aware that it is just a metaphor.

So, I think that this video is great — it helps us imagine something we can’t usually see and relate to scientific content in a new way. Phooey on the naysayers. Does anyone agree with me?

Originally posted on my sciencegeekgirl blog.