Loss of Sea Ice Stirs Up Arctic Waters

The Arctic Ocean is generally considered a remarkably quiet ocean, with very little mixing, because a cover of sea ice prevents wind from driving the formation of internal waves. To study this effect and investigate how melting sea ice might affect ocean mixing in the Arctic, Rainville and Woodgate analyze data from moorings in the northern Chukchi Sea.

They find that when the ocean was mostly covered with ice, even strong winds did not generate much response in it. On the other hand, during the summers when less sea ice was present, wind generated large internal oscillations and increased turbulence.

The extent of Arctic sea ice in the summer has been declining significantly in recent years, likely resulting in increased internal wave generation, the authors note. Because internal waves bring deeper waters closer to the surface, the results have important implications for Arctic Ocean ecosystems and ocean dynamics.

The research is published in Geophysical Research Letters. Authors include Luc Rainville and Rebecca A. Woodgate: Applied Physics Laboratory, University of Washington, Seattle, Washington, USA.

Order of Magnitude

With the power of science we can now calculate this! At least a rough number.

Let's say that teach morning you create a small bit of crud 1mm to a side, so 1mm by 1mm by 1mm, so the volume of this one bit of crud is 1e-9m^3 (or if you like to write things fancy, 10^-9m³). Yeah you have two eyes, but this is a rough calculation, so I'm going to ignore that. I'm also going to ignore that you don't wake up with crud every day of your life. We do however need your lifespan, let's say 80 years approximately, 365.25 days per year, so you live 2.922e4 days, or let's round that off and say 3e4 days. Multiply the number of days you wake up, by how much crud you get each day, and voila, 3e-5m^3.

According to my favorite conversion website, a teaspoon has a volume of around 5e-6m^3, with the result that you actually produce around 6 teaspoons of eye crud in your lifetime.

The Ethics of a Mars Mission

Mars Mission

One thing that keeps flitting into my head when we talk about a human mission to Mars, is the ethics of it. Right now we don't have the ability for anything but a one-way mission, and still I know there are people who would jump at the chance. I seem to recall reading that women astronauts are required to go on birth control, primarily to eliminate their periods, and this already seems like such an invasion of personal choice. Imagine a trip that takes 3 years each way. In a situation like this NASA really will have to take steps to prevent pregnancies, or to be able to deal with them should they happen.

The one aspect that popped into my head today though upon reading the above linked article by Buzz Aldrin is the issue of consent. The standard for experiments performed upon humans (and you can't call a trip to Mars anything but an experiment) is one of informed consent: the participants must be made aware of the risks (and the risks must be below a certain level), and the participants must give consent. Moreover, the participants have the right to with draw consent at any point in time. Missions on the ISS and such are already seriously pushing the boundaries on this one IMO (does the screening of astronauts beforehand allow NASA to get around the ethics board? or is NASA not subject to an ethics board?). How much more questionable in terms of withdrawing consent is a round trip to Mars? What about a colonization trip?

Noble Nobels

Noble Nobel

During WWII, two German Nobel Prize laureates (in physics) escaped to Denmark. When it too was taken over, their medals were chemically dissolved by Danish physicist Neils Bohr and Hungarian chemist George de Hevesy to keep them safe from the Nazis (and to keep the physicists safe as well, as taking gold out of Nazi Germany was a crime). The solution must have just looked like any other bottle of chemicals, because after the war was over, Hevesy precipitated the gold out of the solution, sent it back to the Swedish institution that grants the Nobels, and they generously recast the medals and reawarded them to the two physicists.

This is why we have SI

I have a bottle of a nasal spray that I'm using for allergies, and it says on the label that each spray delivers "50 mcg" of the drug. What in the world is a "mcg"? Do you think they mean μg (microgram), which is 10^-6grams, or in SI units a single spray would be delivering 5*10^-8kg of drug, or do you think they mean m-c-g (milli-centi-grams), which would be 10^-3*10^-2grams =10^-5grams, or in SI units a single spray would be delivering 5*10^-7kg? These are two different values depending upon how I read the label, one of which is the actual amount of drug delivered and the other of which is either 10 times or one tenth the amount of drug delivered.

This is the whole reason we have metric prefixes in the first place, to reduce confusion and have a standard system whose meaning everyone agrees to. Good thing the actual quantity of the drug here doesn't matter to me, I just take my prescribed two sprays.

Easy Elementary Science Projects – Air In The Soil Science Experiment

Science Experiment

Doing easy elementary science projects need not be kept only for science fairs. There are many good reasons why you and your kids should do science experiments all the time.

Here are a few of those reasons:

It gives you and the kids the opportunity to spend some quality time together
Kids love exploring and it is good to use this natural curiosity to teach them basic science without them even noticing.
Science experiments using easy to obtain supplies are also very suitable for homeschoolers.

Our easy elementary science project for today falls in to the category of “fun.” It is a very simple experiment and the kids will be able to do it with very little help from you. You will have to supervise though; otherwise you will have a big mess on your hands!

To start, explain to the kids that the earth consists of rocks, sand, humus, water and air. This is all the “ingredients” necessary for life on earth. Plants, animals and humans all need them in order to be able to survive. In our science project we are going to have a look at soil. We are going to find out how much air is trapped in different kinds of soil.

What you need:

5 Small clear jars
Water
5 Soil samples from different kinds of soil (go exploring with the kids to find samples in different places)
Labels
A pen
A notebook

What you have to do:

Fill your jars halfway full with your soil samples. One kind of soil into each jar.
Mark each jar with a name that will help you remember which soil you placed in which jar.
Fill the jars with water until they are almost full.
Now observe what happens.
You will see that bubbles start rising to the top of the water.
Can you explain why there are more bubbles in some of the bottles than in others?
Make notes of all your results, it is also a good idea to take photos of your result if you are doing this as a science fair project or as part of your science lessons for homeschooling.

You will note that the soil that is the most tightly packed will have less air in it than for instance a soil with lots of humus, taken maybe from a flower bed. Do you think plants grow better in well aerated soil or in soil more densely packed? This can be the subject of a later easy elementary science project. Have fun!