“That’s too watery…too thin,” said Daegan. So we tried some other red liquids, like paint and ketchup. We thought they looked closer to blood, but I told them boys there was a problem with all 3 models: blood was more complicated than this, and not quite a ‘simple red liquid’.

I then posed a different question, and got out 4 empty bowls and blank labels: What is blood made up of? Gareth quickly said, “red blood cells”, so he got to measure out 1/2 c. of ‘red blood cells’ (red hot candies).

Daegan then added “white blood cells”, and put 5 of them (dry lima beans) in a bowl:

Gareth: “Those things…you know…those things that stop you from bleeding when you get a cut. I just can’t remember their name.” Platelets, I reminded him. One Tbsp of platelets (dry lentils), please!

So we got to this point, but the boys were stumped as to what the missing component of blood was:

I told that that if my blood was like they modelled so far, it would have a hard time moving around in my body—all the parts we have so far are solids. “Water!” exclaimed Gareth. “There’s a watery part to blood!” “Oh, plasma!” added Daegan, finishing the thought. He poured out 1/2 c of plasma (light corn syrup). (Note: I kept all the ingredients hidden in the kitchen until the boys came up with the corresponding blood component. I was curious to see how much they had learned from our readings and DVDs):

So now we had a pretty good answer to my earlier question:

And all that was left to do was combine them. After explaining to Gareth that no blender was required—and in fact, if we blended it all together as per his suggestion we’d end up with a misleading model, as he’d see in a moment—the boys mixed things together:

Yielding:

I then asked the boys why blood looks red. “Oh, it’s because of the red blood cells in it” quickly grasped Daegan. “That’s right,” I said, adding: “The liquid part of blood—the plasma—is in fact a slightly yellow-ish clear substance, like our corn syrup,” (which in retrospect I wish I had added some yellow food colouring to). We compared this again to our original red water/red paint/ketchup models, and I thought we were done.

“But other things can get in blood,” said Gareth. “Like germs.” So off I went to the pantry to find a germ model, and came back with a couple green split peas. “Or dirt.” said Daegan. “You can get dirt in your blood when you get a scrape.” Back again to the pantry for a chocolate chip, to be sacrificed in the name of science.

The boys put the germs and dirt in the blood, and then made the white blood cells attack (complete with all kinds of sound effects!):

(Siren wails!) Attack! Munch! Munch! Slurp! Slurp!  

I hope you have fun trying this activity at home. I included lots of detail in this post—yes, perhaps bordering on the pedantic—for a few reasons. I wanted to show you how easy it can be to adapt an idea you see elsewhere for your own home. I included some Socratic-type questions (my natural and preferred ‘teaching style’); I incorporated other skills into the activity (measuring, pouring); I ran with the children’s suggestion about germs and dirt though that was not even on my radar originally. Have fun making this activity work for YOUR kids in YOUR homeschool, and if you put a different spin on it, drop me a comment or send me a link to your blog!

On a related note: A few days ago, we’d watched the Bill Nye DVD on this topic—Blood and Circulation—which contains an outstanding song Blood Stream, based on the B-52s hit Love Shack: “blood stream, baby, blood stream…”. You can see the Bill Nye version here. The boys asked me to play them the original B52s song, which I did during our ‘gym time’ when we were playing musical statues (i.e., freeze when the music stops), and it was a wonderful ‘rabbit trail’ to follow. Hands on activities, candy, AND fun music from Mom’s youth? No wonder the boys are having so much fun with this human body unit!

Just Gareth and I did the first experiment, which looked at the hot/cold receptors in our skin, and where we have higher concentrations of these. You need a glass of hot water, a glass of cold water, some cotton swabs (Q-Tips), and a willing subject with lots of skin exposed (in my case, a gappy-toothed 6-year-old).

We then proceeded to dip the cotton swab in one glass, and then touch it to his skin in various places, like his arm:

Of course, being a 6-year-old, he wanted to touch EVERYWHERE (some of which I vetoed!), or have me do so:

We found that the lips were by far the most sensitive to hot and cold, and the soles of the feet seemed to have the fewest receptors. Daegan did not participate in this experiment, preferring instead to peruse one of the books I’d gotten out last night:

The second experiment is one you’ve probably seen before; it was about the location of taste buds on the tongue. You’ll need 4 small containers with various sweet (sugar), sour (lemon juice), salty (salt), and bitter (vanilla) substances in them, and again some cotton swabs and a willing subject:

Daegan made a drawing of the tongue so we could label where each taste was strongest:

You simply dip the cotton swab in one of the substances, and then stick it on one part of the tongue: the tip, the side, or the back. (For sugar and salt, you’ll need to dampen the swab first so the grains will stick.)

One tip: for the bitter taste—the taste buds are concentrated at the back of the tongue—you’ll need to put the swab quite far back. We didn’t do it far enough the first time, and had little reaction, but when you find the right spot, your reaction to bitter may look like this:

The final experiment was about showing the sensitivity of touch/pressure receptors. You’ll need thick gloves or mitts (my kids couldn’t decide between them, so used one of each), a blindfold (in our case, a rolled down toque. We’re Canadian, eh?) and some household objects, like these:

Note that I chose a few objects that were similar to one another (tennis ball and apple; DVD and book, etc.) to (hopefully) show the boys that it is harder to discriminate among objects with your sense of touch when those sensors are blocked / otherwise engaged (by the thick gloves). The kids donned their blindfolds and mitts and I passed them various objects, and they tried to figure out what they were:

The boys found this a lot of fun, especially Gareth, the ham (who was the one to contribute his pajama bottoms as one of the household objects in the first place):

We then tried discriminating among similar objects with the gloves off, and the boys found it far easier—their sense receptors gave them more information:

All in all, just the sort of intro I was hoping to give the boys for this science topic. If you have any ‘must use’ resources on the human body, please share.

Daegan then repeated the experiment, with the same result, and then Gareth asked me to do the same. “Do I really need to?” I asked. “Do you think the result might be different just because an adult is doing it?” “Maybe,” replied my 6-year-old, and after considering things from his 6-year-old perspective I thought it a reasonable request. After all, adults and kids DO often get different results when they take on tasks in the real world, from cutting safely with a knife to getting the right button in the right button hole. But I tried tearing the folded up paper first before putting it in water (and couldn’t!), explaining to Gareth that to do a science experiment, we need to have what’s called a “control” or point of comparison.

When I was done tearing my wet folded paper, Gareth handed out new sheets of paper and asked us to dip them directly in the water, no folding. I asked if he was wondering if it would work without folding too—did he think the folding made any difference to water making paper weaker? He said he wasn’t sure, hence the experiment. And again, his hypothesis was “confirmed”—water makes paper weaker, whether folded or not.

While this wasn’t the most complicated of experiments, I thought it interesting that Gareth came up with it himself, and that the variables he wanted to test (wet / dry, folded / unfolded, kid / adult) included some that I would not have thought of from my adult perspective.  And I learned it is not just Daegan who has been watching the PVR’ed Mythbusters!

I started by getting the boys outside. Gareth was keen, but Daegan was giving me a definite “get on with the science already!” face. I explained what we were going to do, and then asked them: Which water do you think is more likely to freeze on contact with the cold air? “The cold water, of course!” they replied.

I began by throwing a cup of cold water. It simply splashed to the ground. Nothing exciting here. YAWN!

I then got Jim to come out with a cup of boiling water and throw it. The boys weren’t paying much attention, as they thought it would be no more interesting than my first throw. I mean, if even cold water won’t freeze right away, surely boiling water won’t either. WRONG!

Jim went back in the house to get a second cup of boiling water, this time filling the mug almost to the brim. Ready boys?

Here we go!

Some of the ice fog we created lingered for quite a while:

Much more fun than whining about yet another cold snap this long, snowy winter, eh?

Gareth ran off, returning with a brush to “gently remove the overburden Daddy”:

Daegan followed suit, and the boys spent a few minutes removing the sand. Jim helped scoop the sand away into the bowl to contain the mess, and it wasn’t long before some “fossil bones” began to show:

The boys then switched to finer brushes to get into the crevasses to remove as much sand as possible:

And Jim gave it a final rinse in the tub, while the boys looked on:

Here’s the finished product:

Next time, we’ll make the plaster thinner, use a different and less detailed skeleton than the triceratops Daegan chose (the ribs were too fine to see clearly), and Daegan would like to try it with a lighter-coloured sand so as it does not “stain” the final result as much. (Though personally I like the “been in dirt millions of years / weather-beaten” look). It really was a pretty easy project, and at a fraction of the price of the pre-made dino fossil kits. Give it a go!

He’s watched it several times, and wanted to try it at home. He drew the instructions, and made a list of supplies to get (plaster of Paris from Michaels, and play sand from Canadian Tire; we had everything else):

They began by putting sand in a large plastic bowl, and smoothing it out:

The first T rex skeleton Gareth chose was too large for the bowl, so he ran up to his room to get another. It was small enough that the triceratops skeleton Daegan chose could also fit in the bowl. They pressed the skeletons in lightly:

They then used a squirt bottle to lightly mist the impressions left in the sand, helping the sand stick together in this shape:

They then pressed the skeletons in a second time, ensuring that all parts of the body would be visible:

Then it was time to mix the plaster, in the ratio 2 parts plaster of Paris to 1 part water. Jim bought the giant economy size bucket of plaster, as we both expect we’ll be using it again with our palaeo-crazy boys.

Then it was time to pour it onto the fossil impressions in the sand:

We discovered that we made the plaster too thick; it ‘globbed’ rather than poured:

But no worries—daddy to the rescue! Jim scraped the remaining plaster out and them smoothed it over the sand using a craft (popsicle) stick. Just like icing a cake!

We’ve set it aside to dry overnight. Looking forward to seeing the results tomorrow!

BTW, if you try this at home, in addition to making the plaster a bit thinner, Jim also recommends putting a thin layer of vaseline on the side of the bowl just above the level of the sand. It’s going to be interesting getting our fossil out in one piece tomorrow. But hey—that’s science. Trial and error, learning from mistakes, etc.

The instructor began the class by talking about molecules, and explained that polymers were made of molecules that liked to stick together in really long chains, thousands and thousands or molecules linked together. She contrasted that with water, and got some volunteers to be H20:

She then handed out a polymer to each child (silly putty type), encouraging them to explore it to investigate the properties of polymers. We had kids stretching, shaping, breaking (when you pull too quickly), twirling, etc. their polymers:

Daegan discovered one other property: it bounces! And quite erratically if you haven’t shaped it into a neat ball:

The instructor then handed out a different sort of polymer: a light-weight “packing peanut” (styrofoam chip). She again asked the kids to investigate its properties: does it stretch? bounce? can it be shaped?

After collecting all the styrofoam bits, she filled a beaker with the packing peanuts and added a small amount of liquid (acetone), and swirled:

This showed the kids that this ‘packing peanut’ polymer is indeed similar to the silly-putty type polymer: it just has a whole lot of air inside (which is why it is so light). But if you scrape up what remains at the bottom of the beaker (the packing peanuts were almost all air!), you’ll find that same stretchy silly putty type polymer:

The next demonstration required a volunteer, and Daegan got to participate. She began by holding a clear plastic bag filled with water and a sharp pencil over his head. He was pretty nervous! And then…poke!

But the plastic bag, being a somewhat flexible polymer, formed a seal around the pencil, and nothing leaked! Daegan had to look for himself:

Now what would happen if we changed the flexible plastic bag to a more rigid polymer? She held a water-filled styrofoam cup above his head, and…poke!

This time, as the polymer was not flexible, it did not form a seal, and the water leaked:

And Daegan can now say he has joined the ranks of scientists everywhere, sacrificing himself in the name of science. Or at least getting his shirt wet.

The instructor added acetone to the stryfoam cup (once empty!), showing us the lattice structure of air pockets:

The next demonstration was similar to the bag of water, and involved a vaseline-covered (polymer-covered) skewer and a balloon. That certainly held the kids’ attention:

It took three tries (giving me the opportunity to whisper in Daegan’s ear: “If at first you don’t succeed, try, try again”), but she did get it to work:

Lastly, each kid got to make their own slime polymer, choosing the colour by combining (or not) primary-coloured paint:

And presto! Oopy, goopy, slimy polymer:

Some kids made slime that would be fun for practical jokes. Ah–chooooo!

And some kids gave real meaning to the phrase, “hands-on science”!

Overall, the boys enjoyed this presentation. I thought it was not quite as “flashy” or “whiz-bang” as the previous mad science presentation, which they agreed with, but Daegan pointed out that this one was much more hands-on. And, he added, “I do best when I get to touch stuff.” Thanks again to homeschooling Mom Sandra for setting this up!

The boys and I gave it a whirl today, with a few variations.

If you try this at home, we found it worked better if you put the food colouring closer together, overlapping or even on top of one another. I didn’t do this.

Now, add a drop of dish soap and see what happens. (We added a few extra drops around the edges). Here’s what we got:

It had a kind of hypnotic, lava-lamp like quality. The boys were keen to try their own bowls now that they’d seen how it was done:

I’ll just draw your attention to the background of the next photo, in case you were under delusions of “perfect homeschooling families”. Yup, that’d be our living room, with nowhere to sit between games, dinos and books all over the couches. Can’t clean now, Mom…too busy playing and learning!

We then tried the experiment with other milks. I explained to the boys how it worked, with the colouring suspended in the fat molecules of the milk. We made a hypothesis that the almond milk, being creamier, would work better than the rice milk, which is quite thin. This proved to be correct: the colouring in the rice milk just melded together, like in water, where the almond swirled somewhat, though not as much as the full fat cow’s milk. Here’s the almond milk:

Here’s the rice milk:

We went back to the cow’s milk for our final variation: using 2 colours only. The boys thought the yellow and blue combo was quite interesting, as a dinosaur appeared and then disappeared! Note the skin texture and crest on its head. Clearly a parasaurolophus!

Have fun with this at home.

So today I gathered up some materials we had around the house and did a very spur of the moment “unit study” on Ancient Egypt. We had found a couple promising books at the library yesterday; the Ms. Frizzle title proved to be a very useful introduction for my science- and Magic-School-Bus-loving boys:

Daegan recalled that one of his magazines had a whole issue about Ancient Egypt. (I highly recommend this magazine for kids anywhere. It is ad-free, and covers a wide variety of science topics. The publisher is Canadian, but the content is not. I thank my aunt for getting Daegan a subscription years ago, as it has built upon his love of bugs and dinos to introduce a wide variety of subjects.)

We built a pyramid of sugar cubes, talking about kings and pharoahs, square numbers, and burial rituals along the way:

We wrote our names in hieroglyphics:

We began an experiment to mummify an apple, the details of which can be found here. We did a simplified version:

We cracked some funny (or should I say punny) Egyptian-themed codes:

We read about the Great Pyramid (the boys are very into large numbers and measurement right now):

We moved “heavy blocks” (really, heavy books stacked on top of one another) as they would have when building the pyramid, and discussed how the ancient Egyptians might have made their work easier:

We got out some pencil crayon “logs” and used them to create rollers under the blocks, making the work much easier:

Tomorrow we will continue the Egypt theme by using squares to demonstrate the Pythagorean theorem (which the ancient Egyptians used to reallocate farmland after the Nile flooded each year). And Gareth wants to make date squares, his favourite dessert / snack. After all, as he pointed out to me while we were reading, dates did grow in Ancient Egypt.

If you have other favourite Ancient Egypt activities or resources, please leave me a comment. Thanks!

“We’ll check back on this in a bit.” He then took out some small ice chips and shavings that had fallen off when cracking the ice cubes from their tray, and put them into a separate bowl. He had the boys observe briefly, and asked them what was happening. “They’re melting,” was the reply. “So what do you think will happen if we sprinkle salt over top of the ice chips?”

The boys observed the ice for a minute or two, and Daegan said, “I think they are melting faster.” Jim confirmed this, and explained a bit about saltwater having a different freezing / melting point that regular water. He also talked about how some places salt roads or sidewalks in winter.

He then got two ice cubes and showed the boys how to glue ice together…without glue!

He pressed the two cubes together, pressing the top cube into the salted side of the bottom cube:

Gareth wanted to help, and got his rubber gardening gloves on to protect his hands from the cold: 

And voila! The cubes stuck! (You have to hold them a while as you need enough time for the salt to melt enough of the cube that then re-freezes to the other non-salted cube above, adhering them together.)

So how about that ice cube and string we started with? (Same reasoning: the salt melts some of the cube, the string gets caught in that water, which then re-freezes, trapping the string in ice):

Unfortunately Gareth tried to lift his string too soon, disrupting the process. But this experiment is cheap and easy to repeat. When we were done the boys took the remaining ice cubes, sprinkled them with salt in a bowl, and re-froze to make a giant iceberg. They wanted to play Arctic Animals again.