Rabbi Yose the Galilean says: How does one derive that, after the ten plagues in Egypt, the Egyptians suffered fifty plagues at the Sea? Concerning the plagues in Egypt the Torah states that "the magicians said to Pharaoh, it is the finger of God." However, at the Sea, the Torah relates that "Israel saw the great hand which the Lord laid upon the Egyptians, and the people revered the Lord and they believed in the Lord and in His servant Moses." It reasons that if they suffered ten plagues in Egypt, they must have been made to suffer fifty plagues at the Sea.

According to Rabbi Yose, the destruction of the Egyptian army at the Sea was five times worse than the plagues (one finger of the magicians verses five fingers in God’s hand).

You can use your finger to make the Sea split and then everyone will believe in your ability to perform miracles. Simply take a bowl filled with water. Put ground pepper all over the surface of the water. Then put a little bit of liquid soap on your finger and run it across the water. Watch as your guests are amazed!

haggadah Section: Maggid - Beginning
Source: White Meadow Temple's Seder Experience