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.
Earth Day Flag created by John McConnell. Earth Day is an annual event, celebrated on April 22, on which day events worldwide are held to demonstrate support for environmental protection.t now is observed in 192 countries, and coordinated by the nonprofit Earth Day Network, chaired by the first Earth Day 1970 organizer Denis Hayes, according to whom Earth Day is now the largest secular holiday in the world, celebrated by more than a billion people every year..