The 1940's was a decade of many scientific and drug related discoveries
scientific
World War II was going on in the 1940's. It makes a great reseach topic.
I would say the biggest social issue in the 1940's was the Great Depression and prohibition.
Some of China's Discoveries were when they learned how to make bronze, negative numbers and first law of motion. Some other discoveries were farming and how to make a fire.
Cars were fairly common at this point. In Germany they were working hard on the Volkswagon, or 'people's car'. There are lots of great sites about the 1940s. It won't be too difficult to look up some more about this era.
Gold and Oil.
Archimedes was a great mathematician.
scrap weight unless some one wants it
The Great Depression took place from 1929 to the late 1930s or the early 1940s.
Pansy
Victoria Falls was one of the biggest African discoveries
He discovered the great wall of china