Use scissors to cut the bottom off the plastic bag.
Cut the handles off the other side of the plastic bag.
Cut the top layer of the plastic bag at the folds so you are left with a rectangle. You only need one layer of the plastic bag to make your jellyfish.
Press your finger on the middle of the rectangle, then gather the plastic bag around your finger and scrunch it up to make a ball shape for the jellyfish's head.
Cut a piece of white thread or clear string and tie it loosely around the jellyfish's head. Don't tie it into a full knot yet.
Insert a straw into the jellyfish's head and blow air so that the head is inflated.
Carefully pull the straw out and tie the string tight at the same time, so that you don't lose any air. Tie the string in a double knot to make sure it stays in place.If you want your jellyfish to swim more slowly through the bottle, add 1/2 water and 1/2 air to the head before tying it off.
Cut or tear the bottom part of the plastic into strips to form the jellyfish's tentacles.We preferred pulling the plastic apart with our hands to make more natural looking tentacles, but you can also use scissors.
Continue until you have made your desired amount of tentacles.
Step 3: Make the "ocean" in the bottle
Fill your plastic bottle with water.
Add in 3 - 5 drops of blue food colouring.
Stir the food colouring into the water using the plastic straw. You can also close the bottle and shake it to combine.
Step 4: Add the jellyfish into the bottle
Insert the jellyfish into the bottle. You will need to use the straw to poke the jellyfish down, since the inflated head wants to float.
Close the lid of the bottle tightly.
Tilt the bottle and turn it upside-down to see the jellyfish swim.Your jellyfish in a bottle is complete!