Oxygen in the air. The percentage of oxygen in the air can be measured by passing a known volume of air over hot copper, and measuring the decrease in volume as the oxygen reacts with it. Here are the equations for this reaction: copper + oxygen â copper oxide. 2Cu + O2 â 2CuO.
Get ready - World Backup is March 31st! About World Backup Day is a day for people to learn about the increasing role of data in our lives and the importance of regular backups.
Summer Solstice: How the World Will Celebrate the Longest Day of the Year. The 2014 summer solstice, the longest day of the year, begins this Saturday, June 21 at 3:51 am PDT. Instead of treating this as just another natural phenomenon that comes and goes, places all over the world are taking advantage of the longest day of the year by celebrating this wonderful occasion.