what change did the wwii bring to this minting?
With the entry of the United States into World War II, nickel became a critical war material, and the Mint sought to reduce its use of the metal.
Jefferson nickel
With the entry of the United States into World War II, nickel became a critical war material, and the Mint sought to reduce its use of the metal. 
when was the last year they made silver nickels UNANSWERABLE who is jefferson nickel? The Jefferson nickel has been the five-cent coin struck by the United States Mint since 1938. what is the cent's design? The 1987 modification saw the sharpening of Jefferson's hair and the details of Monticello. was there any redesigning of the front side of the coin? Yes, the design for the nickel debuting in 2006 was designed by Franki.
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Jefferson nickel [SEP] 1938–1945: Early minting; World War II changes
For specialty collectors this 1939 die change also created two varieties for all three mints and proof strikings that year, the "Reverse of 1938" and the "Reverse of 1940", the latter being more common for Philadelphia, scarcer for the other two mints. A 1940 proof with the 1938 reverse has also been discovered. With the entry of the United States into World War II, nickel became a critical war material, and the Mint sought to reduce its use of the metal. On March 27, 1942, Congress authorized a nickel made of 50% copper and 50% silver, but gave the Mint the authority to vary the proportions, or add other metals, in the public interest.