The Dark Side of the Moon
When I was very young, I wondered why we saw only one side of the moon. I was a little odd. Still am.
I set about finding the answer to that question. We didn’t have the Internet at that time. Our family didn’t even have an encyclopedia set. And my fourth grade teacher couldn’t answer the question. I resorted to a quarter coin and a dime.
The quarter was the earth and the dime was the moon. I laid them out on the kitchen table and put my finger on the moon and moved it around the earth. But as I watched, the “moon” showed a different part of itself to the “earth” each time it went around. Only if I rotated the dime once as it went around the quarter did it always show the same part of itself to the quarter. I was astonished.
I also at that time realized that there could not be a dark side to the moon. I performed the same trick with the quarter being the sun and the dime the earth. If all sides of the earth were exposed to the sun then I figured all sides of the moon would have to also. That wasn’t quite 100% of the answer but it was good enough for a nine year old. My mom was unimpressed when I showed her the “trick” with the coins.
As it turns out, that is exactly what happens. The moon rotates exactly once on its axis for each revolution around the earth. Here’s an odd fact: a day on the moon (let’s average it out to 28 earth days) is roughly equal to a year on the moon (the time it takes to make one orbit around the earth).
If you think about it for a moment you’ll realize that the times when the side of the moon facing earth is dark (as in the new moon), the side facing away is in the light. These days the side that faces perpetually away from the earth is most often referred to as the “far side” of the moon. Still this misconception about a side that is always in the dark persists.
I learned recently that the moon was once closer to the earth and that the length of an earthly day was shorter because of it. Because of the influence of the gravity of the moon, the earth has been slowing over the millennia. They call this “spin down.” As a result of the slowing, the moon is moving further away. As the moon moves further away, the earth slows more. It’s sort of a “catch 22.”
They say that eventually, the earth will stop spinning altogether … if our sun lives that long.
As for the moon, they say that because earth’s gravitational influence is so much greater than the moon’s, that the earth slowed the moon’s rotation a long time ago to what we see now.
But I wonder if it will remain so for all the rest of the life of this solar system. Might the moon’s rotation on its axis one day stop completely? Then, if there is still life on this earth, that life would see all the sides of the moon as demonstrated by my dime. Unless, of course, our rotation has slowed so much that it coincides with the movement of the moon. Interesting thoughts.
Tomatoes are a Vegetable
I seem to remember something ridiculous from years ago. I think they were trying to get catsup classified as a vegetable on school lunch menus. OMG.
I have a vague memory of saying something to my husband like, “That’s just too stupid. Tomatoes aren’t even a vegetable to begin with.” He said something like, “Hunh? Whadda ya mean?” Then he got a long lecture. Over the years, he’s learned to keep his questions to himself.
A tomato is a fruit. As I learned way back in community college in a botany class, fruits are basically defined as seed surrounded by a fleshy exterior and result from the ovaries of a flower. And by that definition, a strawberry is not a fruit. It wears its seeds on the outside. Which is a whole different and interesting topic.
Just to be sure, I looked it up and found this: “Botanically speaking, a fruit is a seed-bearing structure that develops from the ovary of a flowering plant, whereas vegetables are all other plant parts, such as roots, leaves and stems. … This includes such botanical fruits as eggplants, bell peppers and tomatoes.” That quote came from livescience.com
Some other “vegetables” that are actually fruits are: beans, cucumbers, eggplant, okra, pumpkins (although I’ve never thought of a pumpkin as a vegetable but I suppose it is similar to squashes and people usually think of them as vegetables), peas, string beans and zucchini (a fruit that is actually a berry). I won’t get into the subcategories of fruits and vegetables right now. Aren’t you relieved?
But. Let’s consider corn. Corn is just weird. The leaves of the corn plant are monocotyledonous. This means the veins in the leaves do not branch. Think of a blade of grass. All grains are monocots and considered grasses: wheat, corn, rye, spelt, oat. Almost no one calls them vegetables or fruits.
But modern corn is a bit different. Whereas, all the others mentioned do indeed produce seeds from a flower, those seeds are generally small and hard. These seeds, other than corn, grow pretty much exposed to the outside world and not at all like the seeds inside an apple or a banana (which by the way is also another special case). In the case of corn, its seeds grow protected inside of the husk. So it can also be considered a fruit. It’s considered a vegetable as well (although I’m really not sure that it should be) because the seeds are harvested and eaten (but we eat oatmeal, so what’s the diff? I don’t get it). And it is also a grain because the seeds can be dried and ground into flour.
It gets even trickier when you find out that some things that should be fruits are not. And not all berries are fruits. And the people who are supposed to know about all this arcane stuff say that lemons are not fruits but are instead a berry. Look it up sometime. Or don’t. Maybe I’m the only one who finds this stuff fascinating.
Salty Water Boils Quicker
Mom didn’t teach me much about cooking. She told my sister and me that because she was the last of nine children and it always fell to her to help her mom in the kitchen because all the older ones had other things to do, that she would never require us to help in the kitchen. No matter how much we begged and pleaded to be allowed to help cook, she denied us. I suspect it really had to do with her control issues.
In any case, the one thing she did tell me was that if you want your water to boil faster, add salt to it. Turns out this is not at all true. Or maybe it is. Sort of. Depends on how you want to look at it. Sadly, so much in life is like that. You think you’ve found an absolute truth and then you find out it’s just not that simple. Like tomatoes being a berry.
This is also from livescience.com: “The temperature of saltwater will get hotter faster than that of pure water,” Giddings said. “But it still has a higher boiling point, and the mass is still greater when you add salt to the same volume of water, so this doesn’t mean that the saltwater boils faster.”
So, why does anything dissolved in water raise the boiling point? Water boils when the molecules are able to overcome the vapor pressure of the surrounding air to move from the liquid phase to the gas phase. When you add a solute (salt or other soluble substance) that increases the amount of energy (heat) needed for water to make the transition, a few processes occur.
When salt (sodium chloride) dissolves you get the ions of sodium and chlorine. These charged particles alter the intermolecular forces between water molecules. In addition to affecting the hydrogen bonding between water molecules, there is an ion-dipole interaction to consider: Every water molecule is a dipole, which means one side (the oxygen side) is more negative and the other side (the hydrogen side) is more positive. The positively charged sodium ions align with the oxygen (negative) side of a water molecule, while the negatively charged chlorine ions align with the hydrogen (positive) side. The ion-dipole interaction is stronger than the hydrogen bonding between the water molecules, so more energy is needed to move water away from the ions and into the vapor phase. Ta da! Thank you thoughtco.com.
We started off on the dark side of the moon and ended up in a pot of boiling water. If we had added some corn on the cob along the way, we’d have really had something.