Such simple items can be transformed into a cool activity that blends both science and art. If you have an empty water bottle, water, vegetable oil and food coloring, you can make this fascinating kid's activity! As a bonus, it also teaches kids about liquid density (and an explanation about that is included in this post!).
Under the Sea Crafts for Kids: Water Bottle Fish, Sock Sea Creatures, Octopus, X-ray Fish, a Math Game, Picture Frame, Puffer Fish, Fish Toy, Sea Turtle, Wind Mobile, Sponge Painting, Fish in a Fish Bowl, Changeable Fish in Water Picture, and a Sea Shell Macaroni Crab.