Blood Cells Under Microscope

After we did the blood typing activity we quickly smeared some of that nice blood onto a microscope slide so we could look at it! We have looked at blood cells before and they're very interesting, but it is harder than you think to get liquid blood! I've tried poking myself with a pin lots of times and I just can't get any blood (my survival instincts won't let me draw blood, I guess!). When I went to donate blood, I actually asked the nurse if I could have one of those little finger-pokers to use later, so I've got that one in reserve! But anyway, we already had some blood after blood-typing, so we leapt at the opportunity. :)

We're no experts in microscopy, so I'm not sure I can describe all the things we're seeing here, but you can definitely see those little flat/round cells! I am not sure if you can tell the red blood cells from the white? The white are bigger, we know. We thought we were picking out some differences but just weren't sure. And of course, my little iPhone photos don't really do justice to what we were seeing. It's hard to get in position a good picture without some sort of attachment for the phone!

We thought maybe that green triangle thing in the bottom left corner was a platelet?

And here is the blood as it was drying and starting to clot.

Fibers and Textiles

Cotton?

I'm lucky enough to have a friend who spins and knits with all sorts of fibers, and she kindly let us look at several of her yarns under a microscope. Unfortunately, my notes on these pictures were a bit cryptic and I'm not sure I got them all right! I will write what I THINK they are, but you can see this page for more (and possibly more accurate) pictures of what various fibers look like at the microscopic level.

Silk?

Mohair?

Wool?

Linen (flax)?

I had a clothing and textiles class in college which was very interesting, and I had tons of fabric swatches from that, if only I could have found them! :) We raided all of our closets instead to find different fabric types, and visited a fabric store for more. The children were delighted to discover, among other things, that some of the boys' ties were "100% silk"! "We live like kings!" they said. :)

Plant and Animal Cells through the microscope

We started this unit with an overview of cells: their structure and composition, and how they work. This was a bit of a review, since we talked about the structure of neurons quite a lot during our nervous system unit. It was interesting to see how, even though the basic parts are the same, the different types of cells in the body can look (and function) so different(ly) from each other! We just learned very briefly about what the organelles do, since that wasn't really the focus of this unit. We did get more in depth about the ribosomes and the nucleus later, as we talked about DNA replication and protein synthesis.

Skin cells at two levels of magnification

Leaf cells (not sure what kind of leaf it was) :)

I remember, very fondly, making a cookie model of a cell in 9th grade Biology, and sometime maybe if we have a unit on just cells, we'll make models too. But I decided against it this time since, again, that wasn't really the main focus. However, I did think it would be very useful to see some cells and get an idea of how they make up all living things, so we got out the microscope and looked at some plant (onion, carrot, leaf) cells, and some animal (skin, blood) cells. We were amazed how much we could see with just our small microscope!

We used some fountain pen ink to dye the onion skin cells, and that was cool. The cells are so neat and orderly! You can see how much structure the cell walls provide. And we were pleased to be able to see the nuclei so clearly with the ink dye.

We also were surprised to see the chloroplasts moving around in and between leaf cells (shown in the video above)! We learned that chloroplast movement helps transport proteins in and between cells, and also allows the chloroplasts to get better access to sunlight, so they don't get stuck somewhere shady and become unable to make chlorophyll. Pretty amazing to watch it happening.

Blood cells—a bit blurry

The blood cells were really interesting too. They were moving around right at first, but the blood dried quickly and then they didn't move. We only looked at blood in the first place because I accidentally cut myself on one of the microscope slides, but then it was so cool that we wished we could look at more of it. I tried to poke myself with a pin but no matter how hard I tried, I just couldn't draw blood! I wished I had one of those poker things they use for your finger when you go back donate blood. We didn't think we saw any white blood cells (although that might be one near the top right edge?), and we would have liked to find some, so we'll be looking for another opportunity next time someone gets hurt around here. :)

Making a Laser Projection Microscope

We learned about this awesome project from The Happy Scientist (subscription required for this video). He gave a great, simple explanation about what to do, and we had no trouble getting it to work. And it was so cool! You can probably find other tutorials for this project online, also. (Yes. Here is one.)

Basically, what you're doing is creating a little loop in which a drop of water can be suspended by surface tension. The water acts like a lens for the laser light to shine through. The light is then projected onto a screen and, voila!, you can see tiny little microorganisms in the water. It is amazing. We used pond water to make sure there would be lots of life in it, and there was! We saw all types of different protazoa, flagellates, etc., with all types of movement going on. Some things zipped across the screen quickly, some sort of lurched along, others were definitely swimming. So cool! This is one of the most impressive activities we did this entire unit, and the children LOVED it. They wanted to show it to everyone who came to our house for the next several days.

It's hard to see anything very clearly in the picture above, but this video is really cool. You can see several organisms moving around in the drop of water, and observe the different ways they move. You should definitely try this project yourself!

Lenses

Resources for learning about lenses:

How lenses for glasses are made

Fascinating page on the Fresnel Lens (used in lighthouses) and we also loved this video showing how they work. Such an ingenious concept!

Here are some lenses we used for experimentation.

While discussing lenses, we used both our microscope (we have this one, which we got a couple years ago and have really loved) and our telescope (this one, which is quite new and we have hardly used it, so I can't say if it's a good one or not. The reviews say it's good for beginners, which we definitely are).

This is a great discussion of why things in a microscope get darker as the magnification increases (and why there is a limit to what we can see with optical microscopes!)

This page tells how lenses are used to make searchlights and car headlights brighter.

We liked these diagrams showing how different lenses can work together in a lens array. Since Sebastian is currently obsessed with digital cameras and how they work, this was particularly interesting to him, as was this page on SLR cameras. There's a cool interactive feature on that page where you can change ISO, aperture, shutter speed, etc. and see how those changes affect the photograph.