Dry Ice or Regular Ice?

     Dry Ice is not like regular ice, this ice is very different. First of all Dry Ice is frozen Carbon Dioxide while regular ice is just water. The temperature of Dry Ice is way colder than that of regular ice. Dry Ice is normally at a temperature of -78.5°C while frozen water is 0°C. Dry Ice does not melt, it goes through a process called Sublimation. Sublimation is when a matter goes strait from a solid to a gas instead of turning into a liquid. Knowing this you cannot melt Dry Ice, it eventually just turns strait into gas form. However when it turns into a gas directly it looks kind of cool like some sort of fog. This is why it is used for purposes such as a halloween party or something else. This can be dangerous because of how cold it is and that it will burn your skin. Also breathing too much of the Carbon Dioxide can be toxic. If you ever are going to use and/or try to dispose of Dry Ice remember not to treat it like regular ice because things will go wrong.
http://van.physics.illinois.edu/qa/listing.php?id=1679

Altitude Sickness

     Over this last break I had the chance to go snow skiing in various places in New Mexico, America. I live in Dallas, Texas which has an altitude of 430ft,  but in New Mexico there were altitudes from 8,000-1200ft. This was a pretty dramatic change for my body and it took a while for me to get used to it. While my body was getting used to this climate change I got this sickness called Altitude Sickness. It isn't a bacteria or virus or like any other illnesses. The cause for this is the low pressure of air and the lack of oxygen. Because of gravity there are more air particles closer to the earth than higher that also means that there is more oxygen at low altitudes than high ones. My body was used to a ton of oxygen and air pressure and then I went to higher altituedes. I had Mild Altitude Sickness which does not last as long and isn't as bad as others. It only lasts about one to two days and you will normally be light headed or have a headache, you will feel nauseous and possibly throw up. Then there is Moderate Altitude Sickness. This has a headache that cannot be healed by any drug, nausea, they will not be as coordinated and may have a harder time walking, and they run out of breath quickly. Last there is Severe Altitude Sickness. This is way more serious and if someone has this they need to get to lower altitude immediatly. Some signs of this are that they will have a pale or bluish skintone, they will run out of breath even when they are not doing anything, they get confused, they cannot walk and fluid buildup in the brain and lungs. If you ever are up in a high altitude place and you or someone else starts to get sick, remember these symptoms and ask yourself if they might have altitude sickness to that you would know how to treat it and they get better sooner and everyone has more fun.

Source:Altitude Sickness Article