It’s all about energy this morning. I stepped outside to recharge my batteries and found painted lady butterflies everywhere. This time to year the painted ladies (Vanessa cardui) are migrating south, with rest stops in places like Phoenix where they can bask in the sun and drink lot’s of nectar from the pretty flowers everyone plants.
It’s in the low 50’s this morning, so the first butterflies I saw were basking on a wall with their wings directed to catch the sun. They are like mini-solar panels.
Why are they basking? Insects bask in the sun to warm the flights muscles prior to flying.
I knew where there were some lantana plants in the sun, so I went to see what was going on there.
More painted lady butterflies basking and drinking nectar. They weren’t cooperative at first, but after sitting still on a cold sidewalk for a few minutes, I was able to get a few good shots.
Here’s one basking on a Texas sage.
Seeing all these beautiful butterflies was a real charge for me. I hope other people notice them too.
If you are interested in learning more, or if you see painted ladies migrating and you’d like to participate in a study, check out the 2008 Vanessa Migration Project. Updated 2019:Â The study is now at Iowa State
One question that has come up (pun intended) from previous posts in this blog is why do pumpkins and apples float? To answer this question, we first need to look at why things float in general.
Do you still have your bin of water? Let’s try floating a few more things.
People have been wondering why things float since olden times. According to legends the ancient Greek, Archimedes, conducted experiments to test why things float or sink. Supposedly he figured it all out while sitting in the bathtub. Our modern interpretation is called Archimedes’ Principle. It states that a body floating in a fluid is supported (or buoyed up) by a force equal to the weight of the fluid it displaces.
Let’s choose water as our fluid. Do you know how much a cubic centimeter of water weighs? How about a gallon?
A cubic centimeter of water weighs 1 gram by definition. A gallon of water (at a given temperature of 4 degrees C) weighs 8.34 pounds. So, in order to float, an item that weighs 1 gram must displace more than a cubic centimeter of water. An item that weighs 8.34 pounds must displace more than a gallon of water to float.
To test this, obtain a piece of modeling clay. Shape it into roughly a cubic centimeter. See if it will float. It will probably look something like this:
(Clay at the bottom).
Now, flatten out the same piece of clay and make a boat shape. A flat bottom with a lip around the edge works well. Place it onto the surface of the water. It should displace a lot more water this time and float. Although the weight of the clay didn’t change, the amount of water displaced did change.
Have you tried floating a can of diet soda versus a can of regular soda? Both are the same size and shape, will they both act the same when placed in water?
Here’s a silent video demonstration.
Why don’t the two identical objects act the same way? According to the box at the bottom of this How Stuff Works page, diet soda has less sweeteners added, so it actually weighs slightly less for the same volume than regular soda. Because they are both mostly water, that slight change is enough to allow diet soda to float. Cool!
Apples and pumpkins are not solid. The pumpkin has a large hollow inside. Both weigh less than the amount of water they displace, and thus they float.
Try floating pumpkin seeds. What about apple seeds? Do they float?
We found that pumpkin seeds floated, but apple seeds did not. The pumpkin seeds are flat and displace an amount of water roughly equal to their size. On the other hand, apple seeds are compact and round. They displace little water. They don’t have to be very heavy to sink.
A few years ago, our family participated in a contest to build a working boat out of cardboard. We started by investigating various boat designs and materials by floating models in a tub. We learned a lot about sinking and floating. You might want to make some paper boats and try them yourself.
As promised, we were able to use the microscope camera unit over the weekend. Here is a photo of a very tiny wasp, in the chalcid group.
This photo doesn’t do justice to the beautiful rainbow colors in the wings and the metallic blue on the abdomen. I’m afraid the camera was a bit dusty.
Wasps of the chalcid superfamily are mostly parasites, which means they lay their eggs in other insects. They are considered to be beneficial insects when their offspring consume pest insects. You probably wouldn’t normally see these wasps because they are so very small, sometime only a millimeter or two in length.
There is an amazing world of tiny creatures visible only under a microscope. This week we have been reading the book “Antoni Van Leeuwenhoek: First to See Microscopic Life” by Lisa Yount. Mr. Leeuwenhoek was not the first person to make a microscope, as sometimes claimed, but he did perfect it and was the first to use a microscope to examine a wide variety of things.
Imagine what it must have been like to be the first person to closely study microscopic life forms as Leeuwenhoek did. He discovered bacteria, protozoa, insects, and even red blood cells. It would have been almost like finding a new planet, sometimes literally right under your nose. No wonder some people had trouble believing him when he told of his discoveries, they were just so fantastic.
If you get a chance, take a look at some insects under a hand lens, magnifier or microscope. You’ll be astonished the details you will see.
