Why high inflation make currency weak?

High inflation makes currency weak because it means that the currency is worth less. This can be seen in WW2 Russia and Germany where it was more cost effective to burn the excess money the people had instead of trying to buy firewood. High inflation means that things cost more while money is worth less. A loaf of bread may go up in price to $10 instead of $2, meaning it takes more of the money to buy the same product.