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Science in Pajamas: Swimming Squid

  • Jul 17, 2018
  • 1 min read

Updated: May 23, 2019


Squid, which are similar to the octopus, have eight arms and two tentacles. The arms, called cephalopod limbs, resemble those on an octopus with suckers along their length. The two extra tentacles have suckers only their ends, and are meant to capture food such as fish and crabs.


Its powerful muscles contract to force out jets of water that propel it in the opposite direction that they’re facing - so it swims backward in a zigzag formation. As a strategy to avoid predators, it can shoot out an inky fluid made from melanin particles called sepia that creates a dark cloud, allowing it to create a diversion and flee to safety.


See the quick movements of a squid for yourself with a homemade creation!


What you'll need:

  • balloon

  • water

  • squirt cap (the type that comes on sports drinks works well)

  • bathtub

Instructions:

Fill the bathtub with water. Then, fill the balloon with water, and while you keep the neck pinched closed, have a friend stretch the lip up over a closed squirt cap. Hold your balloon “squid” underwater one end of the tub or sink, open the cap nozzle, and let go. Water will shoot out of the bottle and propel the balloon in the opposite direction - mimicking a real squid!


If you're interested in the detailed physics behind this movement, here's a great resource.

Resources and References:

  • Littlefield, Cindy A. Awesome Ocean Science: Investigating the Secrets of the Underwater World. Williamson Books, 2006.

  • Zych, Ariel. “Jet Propulsion Locomotion of Squid and Octopus.” Science Friday, www.sciencefriday.com/educational-resources/jet-setting-cephalopods/.

  • Watson, Stephanie. “How Squid Work.” HowStuffWorks, HowStuffWorks, 1 June 2007, animals.howstuffworks.com/marine-life/squid2.htm.


 
 
 

57 Comments


Guest
4 days ago

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Guest
Jun 16

It's fascinating to learn the specific anatomy of squid, like their eight arms and two distinct tentacles for capturing food! Reading about marine life always gets my brain thinking. If you're looking for another way to keep your mind sharp and engaged after reading, you should definitely check out MeowdoKu!

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Guest
Jun 16

This article makes me appreciate the detailed physics of how squid move even more! The idea of jet propulsion and zigzagging reminds me of the cool movement mechanics in some games. You know, if you enjoy games with unique movement and physics challenges, you might really get into StonkRider.

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Guest
Jun 16

I loved learning about how squid use jet propulsion to swim backward in a zigzag pattern and deploy that sepia ink! It paints such a clear picture in my mind. For anyone who wants to visualize these incredible creatures in action, a Text to Image Generator could bring those descriptions to life in a really unique way.

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Guest
Jun 16

This is such a cool experiment idea! I can totally picture trying this with my kids and taking a ton of photos of our balloon 'squid' zipping around. If you're using an iPhone for those pics, a free heic to png converter can be super handy for sharing them online later!

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