Put a small amount of water with food coloring inside the bag, just as the picture shows. The water is the sea. Tape the Ziploc bag to a window where the Sun hits. Take 1 picture of the bag and write the time next to it. What is your hypothesis? What do you think is going to happen? Write it down. Two hours later, take another picture and write the hour next to it. (What happened in those two hours?) Two hours later take another picture and write the hour next to it. (What has changed inside the bag?) Two hours later take a final picture and write down the time.