All matter has a gravitational field that attracts other objects. The more mass an object has, the greater its gravitational field will be. For example, the Earth has a greater gravitational field ...

Iron has a mass number of 56 and is one of the most stable of all the elements. We say that iron has a high binding energy per nucleon. Elements with lower and higher mass numbers per nucleon are ...

The basic principle students should observe and conclude is that mass is conserved in these processes, so the mass should not change. Students may observe slight variations of plus or minus 0.1 grams, ...