What is the difference between coins today and coins in World War 2?

US Coins had different designs and composition during WWII versus modern coins.

Cents: Most cents were made of bronze instead of copper-plated zinc, and they had stylized wheat ears surrounding the Words ONE CENT on the back. In 1943, cents were made of plated steel because copper was needed for the war effort. These coins were silver-gray in color and are the only US coins that stick to a magnet.

Nickels: Buffalo nickels were in regular use, but the new Jefferson design was becoming common. These coins had the same design as nickels made up till 2003, with Jefferson on the front and Monticello on the back. Until 1942 they were made of the same cupronickel alloy as modern nickels, but in the middle of that year the composition was changed to a blend of copper, silver, and manganese so nickel metal could be used in the war effort. These coins were distinguished by large mint mark letters over the dome on the back, and are the ONLY nickels that ever contained silver.

Dimes: Dimes were made of 90% silver and had a different design. They were called "Mercury" dimes because the front had a picture of Miss Liberty wearing a winged liberty cap, looking very much like the Roman god Mercury.

Quarters: These too were made of 90% silver. The design was the same as quarters made until 1998, with a spread-winged eagle on the back.

Halves: Half-dollars were 90% silver and unlike today were in general use. You often got them in change for amounts more than 50 cents. The design was considered to be one of the most beautiful ever on a US coin, with a picture of Miss Liberty walking in the sunrise on the front, and a perched eagle on the back.

Dollars: $1 coins were also 90% silver but were very large (38 mm), heavy coins that didn't circulate much except in the West. The last ones were minted in 1935 so they were already beginning to disappear from circulation by WWII.