Science_News

It actually shouldn’t be much different at all. None of the formulas you use will change, and none of the mass measurements will differ. Something that weighed a kilogram yesterday will still weigh a kilogram today. So for the general public, scientists have tried really hard to keep things from changing.

Scientists, on the other hand, will have an easier time making measurements. For example, if you want to measure a tiny mass of micrograms or smaller, you still have to make a comparison to a full kilogram. That means that there's more uncertainty in your measurement. Now that the kilogram will be based on a fundamental constant, you can use that constant to measure out a mass of any size you like. Plus, we don't have to worry about whether the size of the kilogram changes over time.

Previously, the mole was defined as the amount of substance that has as many atoms (or molecules, electrons, what have you) as there are in 12 grams of carbon-12. Avogadro's constant was a number that scientists measured, that told you how many atoms that was. Now, Avogadro's constant will be a fixed number with no error on it, that is no longer possible to measure. It just is what it is. A mole is then the amount of substance containing exactly that many atoms. And as a result, a mole of carbon 12 will no longer be exactly 12 grams. There will be some measurement error on that number.

There is a wide variety of information you can glean from these genetic tests. Some give information about genetic variants that affect your physical appearance: hair and eye color or whether your earlobes are attached or detached, for instance. You might also learn whether you carry variants that put you at higher risk for some diseases, or variants that you could pass along to your children that would lead to a recessive genetic disease (one in which both parents have to pass on a faulty copy of a gene).

For ancestry testing you can learn how much Neanderthal DNA you carry, what continents your ancestors came from and find DNA relatives.

None of the companies tell you everything about what they find in your DNA.

They are planning to keep Le Grand K under the same conditions for some period of time and to keep studying it. They want to understand if its mass has changed over time, and if so, how much. Now that there is a new definition of the kilogram, Le Grand K might change in mass relative to the new definition. I imagine eventually people will lose interest in it, but I don't really know how long that will take.

I didn't, but it's a good idea. Someone should try it.