This time she would be ready!

Nerida lifted her wand when she reached the front and waited for the balloon to come to her. Not a moment later, it came. She waved her wand, "Arresto Momentum!"

It worked!!!! The water balloon slowed down and she quickly cast the spell again and this time it stopped in its place. She reached up and grabbed the balloon lightly not wanting anymore water and placed it with the others. Then she turned and went back to her desk to collect her belongings.