This jellyfish in a bottle looks just like the real thing! This ocean craft is easy and inexpensive to make, and it’s also a fun discovery or sensory bottle.
Make a jellyfish from a plastic bag and place it in a bottle of water to watch it swirl and “swim” around! It’s really mesmerizing to watch, and it makes a great prop for storytime or a lesson at school.
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How to Make a Jellyfish in a Bottle
Check Out The Video Tutorial:
Step 1: Find what you need
- Gather your supplies and materials.
Step 2: Make the jellyfish
- 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!
- If you’re worried about kids opening the bottle you can glue the bottle lid shut, with hot glue or super glue.
- Don’t add too much food colouring to the water, or else it will be difficult to see your jellyfish.
- Use a larger bottle (we recommend about 1 liter) so that the jellyfish has room to swim.
What is the science behind the jellyfish in a bottle?
The simple answer is that air is lighter than water, so no matter which way you turn the bottle, the jellyfish head will rise.
Water is more dense than air, because there are more water molecules per unit, compared to air. Water molecules form bonds with each other, keeping the molecules together. This, in turn, makes the water heavier, allowing the air to rise.
What kind of container is best to make a jellyfish in a bottle?
We used an 850 ml VOSS water bottle to make our jellyfish in a bottle. You’ll need a clear bottle to place your jellyfish in, ideally one with flat sides, so you can see the jellyfish clearly.
You can also use a larger bottle, such as a 1 or 2 liter soda bottle, because it gives the jellyfish more room to “swim”. You can also place your jellyfish in a mason jar.
What type of bag makes the best jellyfish in a bottle?
We used 1/2 of a produce bag from the grocery store to make our jellyfish and it worked really well. The plastic is nice and thin, allowing you to rip the tentacles using only your hands.
You can also use a grocery bag or a ziploc bag to make your jellyfish. Or try using iridescent film paper or cellophane.
Use recycled items to make this DIY jellyfish in a bottle, and help teach kids why littering is bad. This craft shows how ocean animals, like a sea turtle, can mistake a plastic bag for a jellyfish, which is very dangerous.
It’s important to recycle and dispose of trash properly so that plastic doesn’t end up in the ocean!
Here’s even more fun ideas:
Our book Low-Mess Crafts for Kids is loaded with 72 fun and simple craft ideas for kids! The projects are fun, easy and most importantly low-mess, so the clean up is simple!