The apartment where we have spent the last five winters in the Dominican Republic (DR) is right on the ocean. Here the beach very gradually slopes into the water and we have observed over the years that the high tides have been creeping higher and higher. It has been so gradual that we seldom remark on it but this week we had a storm and that really opened our eyes. The pictures tell the story. The one on the far left was taken in 2008 and shows our building probably at low tide with the flags flying in front of it. The picture to the right of it was taken at low tide a couple of days ago after a storm with high waves had washed away much of the sand.
Shocked by the evidence, I checked to see how much the ocean has risen ever since the ice at the poles began to melt and it is only 20 cm. or 8”. That’s not much! I thought it would be more?
It turns out that most of the ice at the North Pole is floating because there is not much land there. When water freezes it expands a little and floats and when it melts it shrinks back to the original volume of water it was made from and doesn’t add a drop of water to the ocean.
At the South Pole the situation is different – the ice sits on the huge continent of Antarctica and much of it is 2.7 kilometers thick! That means its surface is at an altitude of around 9,000 feet where it’s so cold it won’t melt. A lot of what does melt at the edges is replaced by snow and it will take a long time before the incredibly huge quantities of frozen water to add significantly to flooding.
So how fast is the ocean rising? With global warming, the rate has increased to but a little over one inch in 10 years. That sounds manageable but actually it's an enormous amount of water and, with storms hurling that extra water at our shores, it's causing more and more erosion. If you look at the pictures, that's what we are actually seeing at our winter haven here. Rie
In the last post I talked about water molecules and about the way they behave because of the charges on their surface. Now I plan to do the same thing with soap so I can explain the marvelous ways it behaves when mixed with water! Two representations of a soap molecule are shown in the diagram on the left. The top one showing all the atoms that share or exchange electrons to form the molecule and the lower one a simplified representation of the same thing.
In general soap molecules have a charged head that feels comfortable cozying up to the oppositely charged side of water molecules, and a long tail that has no charges on it so it feels more relaxed being away from anything charged. It turns out oils, greases and fats don’t have any charges so soap molecules tend to bury their tails in them to get away from water.A first for me today, I took a video of an experiment mixing oil and water and then adding soap. I’ve uploaded it to you tube. I hesitate to link it but it’s useful to actually see what happens and as a basis for comparison as I improve. Also it does show how the soap molecules, by burying their heads in oil droplets and exposing their charged heads to water, can form tiny particles called micelles that stay suspended in the water to form a suspension of oil in water.
You will have had the experience of grease sticking to your hands and of finding that water is no good at getting it off. Our hands exude natural oils too and they harbour dirt and bacteria. When we wash them with soap and water, you can now imagine the soap tails embedded in the oils presenting their charged heads attracted to the water and being easily flushed away with it.
There is more to this story and if you are interested - I plan post it today to expand on the marvels of soap and water! Rie
My chemistry teacher, a prim matronly Miss Quinn was surprisingly ‘turned on’ by chemistry. We had learned from her that atoms had a small positive nucleus made up of positive protons [and neutral neutrons that are the glue that holds them together] and negative electrons that are really mobile and buzz around in an orderly way, like bees around a hive. Then I remember so clearly the day she introduced the periodic table - I was totally captivated as I grasped the orderliness of the basic elements in all universe! The element number told you the number of protons and electrons they each had and from the placement of an element in the table, you basically knew its properties. If you followed a few simple rules, you even knew how it would behave.
It turns out that Chemistry was all about the giving and taking, or the sharing of electrons between atoms to form what we call bonds. When that happened, entirely new substances are created.
For instance, if you mix hydrogen gas with oxygen gas and give them a spark to get them going, they are so anxious to share electrons that they violently explode, the two gases disappear and liquid water appears. A miracle - but it's an understandable one!
Why is water, H2O, liquid? Oxygen is is #8 in the table so has a nucleus with 8 positive protons that have a strong pull on hydrogen’s shared electron and that makes molecules of water have uneven charges and and they stick together like slippery little magnets.
Cool them down and they move more slowly until they finally stick together forming an open patterned network we call ice that floats because of the holes in its structure. Heat it up, and the molecules move faster, the pattern breaks down, ice melts and finally when hot enough, water molecules move so fast they overcome their attaction for one another and separate to form a gas, water vapour.
Chemisry can get complicated but the more we figure out the rules by which it’s playing, the more logical and understandable and fascinating it becomes.