dirtyamerica

We don't want to confuse weight with mass. Sure, the spoilers pushing down on the car would make it weigh more on a scale but the mass of the car stays the same (besides the burning of the fuel, tire wear, etc.) A car with so much mass will have so much inertia, preventing acceleration, no matter how much it is pushing down on the ground. Imagine a bowling ball hanging by a helium balloon. It weighs nothing but will still be difficult to push because it's still made up of more and denser "stuff" (atoms). Or a balloon and a bowling ball inside a space station. Both have zero weight but trying to move the bowling ball will still be more difficult. Weight is a function of gravity (or the downforce of wind). Mass is a function of the amount of elementary particles that the object is made of.

To get 1 gallon of clean water (or "permeate") it will require 1.33 gallons of "feed" water. Typical reverse osmosis units run at a 75% recovery rate (or how much clean water you make). You need a certain amount of water going to waste (called concentrate) to remove the impurities that are left behind. A proper set-up like this will also prevent the membranes from scaling up. ROs are more effective if you are using water that has already been clarified, filtered and degasified.

IIRC, Earth was closer to the sun about 8 months ago than now during its perihelion.

and don't forget to add the acid SLOWLY, not all at once!

or pH paper. Check your local hardware store for swimming pool supplies. They may have a pH test kit.

sound waves also refract

I agree as I work with it frequently (water treatment). The essence of the hand-warmer I once read about and mostly forgot was that a CaO packet is sealed from the atmosphere in its packaging. Once you open the wrapper and knead the warmer the oxygen reacts to the Cao, releasing heat. The calcium hydroxide doesn't leak out of the package because (I forget).. I'm not too helpful but I tried!

I remember reading somewhere about hand warmers made with calcium oxide. ( http://en.wikipedia.org/wiki/Calcium_oxide ) Maybe the above link will help. be safe

copper ions work too

The best way to teach Science is hands-on, whether through lab work or just good old concrete examples. You can drone on about theories but once you give students something tangable to work with it's like magic. I used to teach sciences in a middle school. Fortunately at that level you can stay away from huge equations that might scare some kids. My philosophy was to trick them into liking Science by distracting them with cool stuff. hehe Students learn more by doing Science and applying higher level thinking skills (analyzing, infering, etc), not just by seeing or hearing it.

interesting concept. I've noticed that on some color-coded periodic tables they don't assign H a color.

There is a temperature gradient. It's the why weather stations' thermometers are placed at a standardized height of 4 or 5 feet off the ground.

I haven't read all the way through this thread so forgive me if I'm posting something that's already been said! Science should always be approached in a skeptical perspective, but at the same time, maintaining a "hopeful" one. Nothing in science is a given unless it's a law, up until it's proven...anything is possible. My philosophy on religion and science is that you cannot use either of these to argue, say for example, "how we got here". That's an argument using apples and oranges. They are two totally different trains of thought. So a theologist debating existence (for example) with a scientist is a waste of time because neither persons' ideas can absolutely, without a doubt, be proven. My answer to your question: NO. Whether you're a religious person or not, as a scientist, you shouldn't discount all that is possible. Flat-out believing in everything that was written in the Bible (example) and trusting those who authored it, is the same scenario as being a scientist who is an atheist. Personally, I think that science is a way of proving how God works (via laws, theories and facts), which supports some of what was written in the Good Book (discounting what was surely written out of current societal norms and other cultural "spiciness"). I'm thankful that God has given me the patience and intellect through what we call science to learn about the wonderful gift of this universe and the life He gave us.

also if they have a higher vapor pressure

I once read that it has something to do with how your brain processes events in early childhood..and once these cause/effect relationships are established, they stay with you for life. in my personal experience of this phenomenon (realized at or before kindergarten): for single digit numbers: odds = wet evens = dry anyone else have this? Other than that I have certain chapters of my life that associate with certain feelings or "thought smells" but I can't quite pin a sense to it.