Z and I had a conversation about 911 earlier today - what it used for, why it is a short number, what types of situations she might need to call 911 for and what she should say if she did, and "how much" someone would be bleeding if they cut themselves so bad that an ambulance would be necessary. Thus the amount of blood in the human body arose as a significant question.

We did a quick web search and came up with a figure of six quarts of blood in an average adult. (Later, and perhaps better figures would knock this down closer to five quarts, but I have no regrets.) This means very little to a five-year-old; even showing a one-quart liquid measuring cup and saying "six of these" doesn't help much, because kids that young can't really visualize and estimate volumes. So we decided to make six quarts of "blood," to get a sense of just how much that was.

It all went down in the bathroom, where knew we could clean up any mess we made without much hassle.


We used this hair clip board to count quarts as we went. With each quart we poured into the larger container, Z "opened the doors" in one of the hair clip slots.


The red food coloring was the master stroke that made certain Z would both remember and understand what we were doing. Above, Z contemplates the volume of blood that is supposedly coursing through my body.

The next step was a discussion of the fact that she undoubtedly had considerably less blood. We did some quick math and guessed that although she was about 1/4 of my weight, she might have up to 1/3 of the amount of blood in her body that I had in mine. We really had no reason to think that, but it seemed like a decent guess, and I didn't want to slow down our progress by looking for more facts.

That's when things got really interesting, though, because after calculating how much blood we were going to measure back out of the container, we decided we'd take pictures of each of us with the quantity of blood that was in our bodies. In other words, it meant Z was going to get her hands on our Nikon D40. She's a pretty careful kid, but that camera is pretty heavy for a five-year-old.






In a way it seems like a lot of blood to have in your body... doesn't it?

When we removed the blood from the container to "draw down" to Z's level, she "closed doors" back up in our counting card and was able to tell me when we had removed enough.


This seems like a shockingly small quantity of blood for anyone to have, especially since we were probably overestimating. It's realizations like this that make kids' toughness in the face of great vulnerability so shocking, and so inspiring.


This photo is a few months old, from the time Z ran out of a restaurant more or less straight into a pole. There was a lot of blood at the time, and it didn't help that her tears mixed with it, reopening it several times as it healed. Clearly, though, there was plenty of blood left over.

Jeremiah and Z have been saving up a variety of items for another "Nature Box," and spent a couple of hours this weekend putting it together. It's more varied than their previous nature boxes, and includes:

• A real or concrete-generated fossil of a small clamshell Z found in our driveway


• A tuft of animal fur from the road, probably rabbit


• Half of a geode purchased at a museum and smashed in our driveway with a hammer


• A painted shell Z bought in on a trip to Galveston with her grandmother


• A dragonfly found in our yard


• Two moths, one found on our porch and the other in our garden


• An inch-long thorny leaf tip from a century plant (large agave) from our driveway


• A dead ladybug and a dead cranefly, both from our home office


• Part of a bird's egg found on a walk in a local park

One of the most interesting developments for this project, though, was the "map" they created in the box lid to identify specimens. Jeremiah drew circles to indicate each object, and then Z labeled them, and learned in the process how the "map" (a legend, really) can show a viewer what is in the box, without directly labeling the objects themselves. We've been working a lot on maps lately - a topic we'll discuss in another post soon on Punnybop, as it all started with a couple of great kids' books - and this plays into that learning well. As Z is busy learning to write, we are also very keen to use applications that are highly purposeful and meaningful to her, and labeling something she can refer to later offers tangible evidence of the value of writing things down!

The New York Times has an interesting piece on a new miniature golf course at the New York Hall Hall of Science that helps teach kids astrophysics:

At the geosynchronous-orbit hole, where the ball swirls around a large bowl before dropping into an opening, Dr. Shara showed the boys how the ball was following parabolic arcs that kept abruptly changing, or precessing.

“This happens in real space time, too,” Dr. Shara said, explaining how objects would follow similar paths down into a black hole, and how Mercury’s parabolic orbit precesses. “The Sun’s gravity is warping the space around it, so Mercury does the same crazy kind of thing that the golf ball just did.” [Link]

This isn't the first time a science museum has used mini golf to teach science. Ithaca's Sciencenter has a similar astrophysics "course" and The Science Museum of Minnesota has an intriguing "Earthscapes" miniature golf course that "provides a fun - and challenging - way to learn how water moves from mountains to oceans and shapes the landscape along the way. With water hazards like you've never seen before, this 30,000 square-foot course demonstrates that rivers and streams are alive and ever-changing!"

Z and I love digging into old toys, taking out useful parts, and repurposing them. Regular readers may recall our homemade robots, which I'll pull up from the archives this weekend and post here on our new site. But we have a harder time learning about the inner workings of toys we don't want to break.

Artist and medical student Satre Stuelke has found a way. He uses "an older four-slice CT scanner" to capture radiological scans of children's toys, presenting them both as objects satisfying our tinkerers' curiosity and as art.


Barbie, as it turns out, has amazing bone structure.


This toy rocket's simplicity is satisfying on a number of levels.

You can find larger views, dozens more examples, and 360-degree scan videos on Stuelke's Radiology Art website. Stuelke will also hear you out if you have an object you think he should scan. He also sells limited-edition prints - I didn't dare ask the price.

[Via NYT]

If you haven't yet read Fast Company's article about the history of the chemical industry's efforts to resist BPA regulation, you should check it out. It's a long piece, so I just got around to reading it. But it offers great detail on the conflicts of interest and fudged studies that have plagued the industry side of this issue. It's also great at giving you a sense of how carefully studies must be scrutinized for their validity, and why repeatable results are so important in scientific research. Here's just one example from the article:

The largest and most influential industry studies have been conducted by Rochelle Tyl of the Research Triangle Institute, a private lab in North Carolina. Tyl's first BPA study, published in 2002 at a cost that Tyl puts at around $2 million (also funded by the Society of the Plastics Industry), examined three generations of rats and found no adverse effects at low doses. Yet here, too, there are questions of protocol. The study used a rat strain called the CD Sprague-Dawley, which has been shown to be insensitive to synthetic estrogens like BPA. (A Japanese study found that the CD Sprague-Dawley rat can withstand a dose of synthetic estrogen more than 100 times greater than what a female human can tolerate.) As of early 2007, of the 29 studies that have shown no harm due to BPA, 13 have used the CD Sprague-Dawley rat. Nonetheless, when the FDA declared BPA "safe" this fall, it relied almost exclusively on Tyl's work -- a shortcoming that the agency's science board publicly criticized in October.

It's cases like this that are worth keeping in mind whenever you hear about a single, groundbreaking study that poses an emergency for everyone. Sometimes the worrying results of a single study are enough to change our behavior, particularly if it is published in a rigorously peer-reviewed and highly respected journal, but an accumulation of evidence validated by other researchers is what good science really demands.

Read the full story here.

A "visible man" is about the best substitute I know of for having an actual cadaver in your home, and saves on freezer space. This one, by SmartLab, comes with a 32-page book featuring information about organs and the body systems covered (skeletal, vascular, and muscular) and, crucially, tells you how to put the organs back into the body after pulling them all out. Of course, you can also just stuff them in there, and you can jam the tweezers in the body cavity, too!


At four, I have to admit Z is far more interested in torturing this poor mini-man by making him wear his diaphragm as a hat. I'm looking forward to getting some seriously productive use out of this model in the next year or so. The book walks through the process of food digestion, which any ravenous kid should be able to relate to once their attention span catches up with their mental capacity.


The man comes with a stand so he can be displayed when not in use. Available for $27 on Amazon.com.