We should use this amazing mechanism that's inside a grasshopper leg

Also, the hinge from an overhead cabinet! That's like the last mechanism too. The sponsor is Incogni: Take your personal data back with Incogni. Use code SCIENCE at the link below and get 60% off an annual plan: incogni.com/science

This video is all about storing energy slowly and using it quickly, but there might be interesting instances of the opposite as well. For example, when winding a mechanical clock, you are storing energy quickly and then using it slowly. The purpose there is to allow the energy to be released over the coming week so that you don't need to apply energy continuously to keep it going.

Mantis shrimp: offended

15:06 "...your arm is QUIVERING holding the bow at full draw." Good one.

Ballistic Seed Dispersal (ballochory) - cress pods, touch-me-nots and others, tension is stored in a 'just barely stable" state in the pod wall, the smallest disturbance tips the balance and a huge elastic release of force expels the seeds.

The linkage you are thinking of is called an over-center mechanism and they are used everywhere! Some common examples would be vice grip pliers, toggle latches, and clamps.

The last mechanism reminds me of staplers -- when you open them up to refill them, there is a similar mechanism with a hinge and a spring.

I love how for the example of a catapult you used a trebuchet, the superior siege engine.

Here in Western Australia we have the "trigger plant". Evolved to trap insects for pollination or some species for consumption. The stamen and style of the flower are fused into a column, which can look like a club. The column is slowly pulled back under the flower and "locks in place, when a insect lands on the flower and touches the trigger hairs the column is released and strikes the insect where it is stunned and releases previously collected pollen for fertilization or trapped to be slowly dissolved for food. The strike is one of the fastest movements in the plant kingdom, taking as little as 15 milliseconds.

Says calling it a catapult would be confusing and shows a trebuchet. 🤔

Okay so never in my entire life have I been able to snap my fingers due to inadequate explanations of what I'm supposed to even be doing and then at the age of 42 a single Steve Mould explanation has me doing it first time. What a world we live in.

I saw that bistable switch model before in a Veratasism video called "Why machines that bend are better." All good electrical switches have a mechanism that stores energy one way or another to make sure the contacts close firmly or open completely. There is always an energy hump as the mechanism goes from one stable state to another, which is why there is a snap action. As the contact points come together, the motion continues just a bit before it stops. This causes a wiping action that cleans the contacts so they work reliably. The handle that you touch and the inner electrical part are connected with a spring, so two bistable parts work together. That way, the handle can be at that state in between the stable points and the electrical part is fully stable.

There's a window-breaking tool that does that sort of thing. My mate had one years ago. It's a heavy, cylindrical metal device with a moving spike inside like a plumb-line weight. You push the pin back harder and harder, then it suddenly juts out with a force sufficient to easily break toughened glass.

Hi Steve. An example of the mechanism you showed can be found in the human body. The "tensor fascia lata" originates from the pelvic bone "the iliac crest" and inserts onto the outer side of the knee. It is a long thick fascial structure that is tightened by a small muscle originating from the pelvis called "the tensor fascia lata". This muscle's function is intriguing, as it spans and controls two major joints -the hip and the knee-, and operates as a joint extensor when these joints are in extension, and a flexor when these joints are at 20 degrees or more of flexion. It effectively operates as a locking mechanism for the hip and knee to allow us to stand without having the spend too much energy through the major muscles -glutes and quads-. Its resistance to motion follows the same pattern of change that you highlighted in your hinged joint with an elastic band, and is least effective at 20 degrees of flexion.

I noticed as a kid the best way to catch a grasshopper was to get it right after it landed, as it seemed to take a second or two to get itself ready to jump again. It would then jump half cocked, only going a short distance, making the follow up quite easy.

You are such a good science communicator. Even for someone who knows a bit of "everything," you make me grasp basic concepts that I've had a hard time wrapping my head around since forever. Sometimes, learning things is all about having the right teacher, because that can literally change the way you think about things. Nothing better than getting that tingle in your mind when you suddenly truly grok something you've struggled with, or just understand by rote memorisation.

At the door of the electric ovens, there is a similar mechanism with a spring. Many greetings from Chile, Steve.

"I want to get this ball moving fast enough to–" I gotcha, gunpowder!

THE KNEE! The mechanism can be found in our knees. The force of the rubber band is the gravitational force on our upper body. This way we don't need much energy standing upright. Also, this is the reason why the toggle mechanism is called 'knee lever' in German :)

Pedersen semiautomatic rifle of the 1920s used a toggle delayed blowback mechanism. Wikipedia has an article about it with diagrams.