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

Steve Mould
30 Apr 202419:18

Summary

TLDRThe video script explores the fascinating mechanics of a grasshopper's leg, which allows it to jump with incredible height and speed, overcoming the limitations of animal muscles. It compares this to human solutions, such as the slingshot, which uses elastic potential energy to amplify force. The grasshopper's leg contains a specialized exoskeleton that acts like a spring, storing energy and releasing it quickly for the jump. The video also delves into various power amplification mechanisms found in nature, like the froghopper's acceleration and the trap jaw ant's catch mechanism. It highlights the ingenuity of biological adaptations and draws parallels to human inventions, emphasizing the shared principles of mechanical advantage and energy storage. The script concludes with a discussion on data brokers, the privacy concerns they raise, and how the service Incognit can help individuals protect their personal data by automating the process of data removal requests across multiple companies.

Takeaways

  • ๐Ÿš€ The grasshopper's leg contains a clever mechanism that allows it to jump high by overcoming the limitations of animal muscles.
  • ๐Ÿ”ฉ Humans use tools like slingshots and bows to amplify power, storing energy slowly and releasing it quickly, overcoming muscle limitations.
  • ๐ŸŒŸ The power output of muscles is limited; they can apply a large force slowly or a small force quickly, but not both simultaneously.
  • ๐Ÿฆ— In grasshoppers, a specialized exoskeleton acts like a spring, storing elastic energy that can be released quickly for a powerful jump.
  • ๐Ÿ”„ The flexor muscle in a grasshopper's leg uses mechanical advantage and a pivot point to hold against the stronger extensor muscle during energy storage.
  • ๐Ÿ”‹ Nature employs various mechanical power amplification mechanisms, such as in the froghopper and the trap jaw ant, which store and release energy effectively.
  • ๐Ÿ”ฌ The video discusses a unique mechanism where an object becomes easier to move just past a certain point of energy storage, similar to a compound bow.
  • ๐Ÿงต The slingshot spider is a rare example of an animal using an external source (its web) for mechanical power amplification.
  • ๐Ÿ“ˆ Data brokers collect and sell personal data, leading to targeted ads, robocalls, and potential data breaches, compromising individual privacy.
  • ๐Ÿ›ก๏ธ Incognito is a service that helps users remove their personal data from various companies, providing a solution to the challenges posed by data brokers.
  • ๐ŸŽฏ The video concludes with a call to action, encouraging viewers to subscribe for more content and highlighting a promotional offer for Incognito.

Q & A

  • How does the mechanism inside a grasshopper's leg allow it to jump high?

    -The grasshopper's leg contains a specialized exoskeleton that acts like a stiff spring, storing elastic energy. The extensor muscle applies a large force slowly, which stores energy in the spring-like exoskeleton. When the flexor muscle releases, the energy is delivered quickly, allowing the grasshopper to jump high.

  • What is the fundamental limitation of animal muscles that humans also face?

    -The limitation is that muscles can either apply a large force slowly or a small force at high speed due to their maximum power output. This trade-off means that muscles cannot generate high force and speed simultaneously.

  • How do humans overcome the limitations of muscle power?

    -Humans use tools to amplify power. For example, a slingshot stores energy as elastic potential energy when pulled back with a large force, and then releases it quickly to propel an object with high speed.

  • What is the role of the flexor muscle in a grasshopper's jumping mechanism?

    -The flexor muscle holds the leg in place against the force of the extensor muscle. It does this by leveraging mechanical advantage and a bump inside the knee joint, which allows the flexor to hold the leg in place until it releases the energy stored in the exoskeleton.

  • How does the Trap jaw ant use a catch mechanism to amplify its power?

    -The Trap jaw ant holds its jaw open using a catch mechanism that requires a small force to release. It slowly builds up energy behind the jaw and then releases the catch with a small force, causing the jaw to snap shut quickly on its prey.

  • What is the significance of the specialized exoskeleton in a grasshopper's leg?

    -The specialized exoskeleton in a grasshopper's leg is stiffer and better for storing lots of elastic energy. It bends like an archer's bow, storing energy that can be released quickly for a powerful jump.

  • How does the slingshot spider use mechanical power amplification?

    -The slingshot spider stores elastic potential energy in its web and then transfers all that energy suddenly into the web and its own body to catch prey, using something external to its body for mechanical power amplification.

  • What are data brokers and why are they a concern?

    -Data brokers are companies that gather personal information about individuals and sell it to other companies. They are a concern because they can lead to targeted ads, robocalls, and even supply lists of vulnerable people to scammers. Additionally, data breaches can expose personal information to criminals.

  • How does the incognito service help with the problem of data brokers?

    -Incognito offers a service that automates the process of contacting different data broker companies on behalf of individuals to request data removal, helping to protect their privacy.

  • What is the difference between a frog hopper and a grasshopper in terms of their jumping mechanisms?

    -The frog hopper achieves one of the largest accelerations in the animal kingdom by pulling its leg up against its chest and using an elastic mechanism to store energy, which is then released quickly. This is different from the grasshopper, which uses a stiff exoskeleton to store and release energy for jumping.

  • What is the concept of mechanical advantage in the context of the flexor muscle in a grasshopper's leg?

    -Mechanical advantage refers to the ability of a system to amplify force, allowing a weaker force (like the flexor muscle) to hold against a stronger force (like the extensor muscle). In the grasshopper's leg, the flexor muscle uses a mechanical advantage due to its tendon's position and a bump in the knee joint to effectively hold the leg in place.

  • How does the human body use a similar mechanism to the grasshopper's leg in a different context?

    -Clicking fingers is an example where the human body uses a similar mechanism to the grasshopper's leg. The thumb and finger are pressed together to slowly build up elastic energy in muscles, tendons, and joints, which is then released quickly to produce a snapping sound.

Outlines

00:00

๐Ÿš€ Muscle Limitations and Power Amplification

The first paragraph discusses the limitations of animal muscles, particularly in humans, and how we overcome them using tools. It explains the trade-off between applying a large force slowly or a small force quickly, which is a fundamental limitation of muscles. The paragraph uses the example of throwing a steel ball to illustrate this point and then introduces the concept of mechanical power amplification devices, such as a slingshot, to overcome these limitations. It sets the stage for comparing human solutions to the natural mechanisms found in grasshoppers.

05:01

๐Ÿฆ— Grasshopper's Jump Mechanism

The second paragraph delves into the specific mechanism within a grasshopper's leg that allows it to jump high. It describes the two tendons in the grasshopper's leg, the extensor and flexor, and how they work with the muscles to create movement. The paragraph highlights the grasshopper's ability to store energy in a stiff exoskeleton before releasing it quickly for a powerful jump. It also explains the mechanical advantage the flexor muscle has over the stronger extensor muscle due to the leverage and the knee joint's design, which allows the grasshopper to hold its leg in place before jumping.

10:01

๐Ÿ”‹ Power Amplification in Nature and Human Inventions

The third paragraph explores various power amplification mechanisms found in nature, such as the froghopper's acceleration and the trap jaw ant's catch mechanism. It draws parallels between these natural mechanisms and human inventions like spud guns and crossbows. The paragraph also discusses an interesting mechanical principle where a device becomes easier to open as the elastic medium becomes more stretched, only requiring a small force to close once past a certain point. It invites viewers to think of natural examples of this principle and mentions a few human applications, like the compound bow and boomerang cards.

15:02

๐Ÿ“š Data Brokers and Privacy Concerns

The fourth paragraph shifts the focus to the issue of data brokers and privacy. It explains how data brokers collect and sell personal information, leading to targeted ads, robocalls, and even scams. The paragraph emphasizes the challenges of dealing with numerous data brokers and the risks of data breaches. It introduces incognit, a service that automates the process of requesting data removal from various companies on behalf of individuals. The paragraph concludes with a promotional offer for incognit and an encouragement for viewers to subscribe to the channel.

Mindmap

Keywords

๐Ÿ’กGrasshopper's Leg Mechanism

The grasshopper's leg mechanism is a biological marvel that allows the insect to jump with incredible force and height. It is a complex system of tendons and muscles that overcomes the limitations of animal muscles by storing energy and releasing it quickly. In the video, this mechanism is compared to a slingshot, demonstrating how it uses a large force to extend the leg rapidly, enabling the grasshopper to jump.

๐Ÿ’กMuscle Limitations

Muscle limitations refer to the physical constraints that muscles face in generating force and speed. The video explains that muscles can either apply a large force slowly or a small force quickly, but not both simultaneously. This is a fundamental challenge that both humans and animals face, which is addressed through the use of tools or, in the case of grasshoppers, a specialized leg mechanism.

๐Ÿ’กPower Amplification

Power amplification is the process of increasing the output power of a system beyond what is naturally achievable. In the context of the video, it is how humans and certain animals overcome the limitations of muscle power. Tools like slingshots and bows, as well as the grasshopper's leg mechanism, are all examples of power amplification devices that store energy slowly and release it quickly to achieve high performance.

๐Ÿ’กElastic Potential Energy

Elastic potential energy is the energy stored in an elastic object when it is stretched or compressed. The video discusses how this energy is utilized in various power amplification mechanisms, such as the slingshot and the grasshopper's leg. The energy is stored when the object is deformed and released when the object returns to its original shape, resulting in a rapid release of energy.

๐Ÿ’กMechanical Advantage

Mechanical advantage is a measure of the force amplification achieved by a tool or mechanical system. In the video, it is used to explain how the flexor muscle in a grasshopper's leg can hold against the stronger force of the extensor muscle. The mechanical advantage is achieved through the leverage provided by the positioning of the tendons and the knee joint's structure.

๐Ÿ’กExoskeleton

The exoskeleton is the external skeletal structure of an arthropod, providing support, protection, and a means of attachment for muscles. The video highlights a specialized part of the grasshopper's exoskeleton that is stiff and capable of storing a significant amount of elastic energy, which is critical for the powerful jumping mechanism.

๐Ÿ’กTrap Jaw Ant

The trap jaw ant is an example of an animal that uses a catch mechanism to amplify its power. The video describes how this ant uses a large force to slowly build up energy behind its jaw, which is held open by a catch mechanism. A small force then releases the catch, allowing the jaw to snap shut rapidly, demonstrating another form of power amplification in nature.

๐Ÿ’กData Brokers

Data brokers are companies that collect personal information about individuals and sell it to other businesses. The video touches on the issue of data privacy and how data brokers can pose a risk by selling personal data, including health information, and contributing to targeted ads, robocalls, and even scams. The video also introduces a service that helps individuals remove their data from these brokers.

๐Ÿ’กCatch Mechanism

A catch mechanism is a device or system that holds back a force until it is released. In the video, it is mentioned in the context of both human tools, like crossbows, and natural mechanisms, like the trap jaw ant's jaw. The catch mechanism allows for the storage of energy that can then be released quickly to perform a task, such as capturing prey or launching a projectile.

๐Ÿ’กSlingshot Spider

The slingshot spider is a unique example of an animal that uses an external structure (its web) for power amplification. The video describes how this spider stores elastic potential energy in its web and then transfers that energy suddenly to catch its prey. This is an exception to the general rule that animals use only their bodies for power amplification.

๐Ÿ’กIncognit

Incognit is a company that offers a service to help individuals protect their personal data from data brokers. The video explains how Incognit automates the process of requesting data removal from multiple data broker companies on behalf of the individual. This service is highlighted as a solution to the challenge of dealing with numerous data brokers that hold personal information.

Highlights

Grasshoppers have a unique mechanism in their legs that allows them to jump high, overcoming the limitations of animal muscles.

Human muscles face a fundamental limitation in power output, which can be overcome using tools like slingshots and bows.

The grasshopper's leg contains a specialized exoskeleton that acts like a spring, storing elastic energy for a quick release.

The flexor muscle in a grasshopper's leg, despite being weaker, can hold against the stronger extensor muscle due to mechanical advantage and a bump in the knee joint.

Mechanical power amplification mechanisms are found in various forms in nature, such as the frog hopper's acceleration and the trap jaw ant's catch mechanism.

The video explores the concept of power amplification in nature and compares it to human-made tools, like a barbecue lighter and a pistol hammer.

A unique compliant mechanism is demonstrated, which gets easier to open as the elastic becomes more stretched, similar to a lever arch file.

The slingshot spider is a rare example of an animal using an external source for mechanical power amplification, storing energy in its web.

Data brokers gather and sell personal information, leading to issues like targeted ads, robocalls, and potential data breaches.

Incognit is introduced as a service that helps users remove their personal data from various companies, automating the process of data deletion.

The video discusses the innovative use of mechanical principles in nature and how humans have emulated these in tool design.

The grasshopper's jumping mechanism is an example of a biological power amplification system that stores and releases energy quickly.

Different animals have evolved unique ways to amplify power, such as the frog hopper's extreme acceleration and the trap jaw ant's rapid jaw closure.

The video uses a model to illustrate the complex interaction between the flexor and extensor muscles in a grasshopper's leg during a jump.

The concept of power as force times speed is explained, showing why muscles can't apply a large force quickly, leading to the use of tools.

The video highlights the importance of understanding the natural world's exceptions to rules, such as mammals that lay eggs and fish that fly.

The video concludes with a call to action for viewers to subscribe and engage with the content for more informative videos.

Transcripts

00:00

this is the mechanism inside a

00:01

grasshopper's leg that enables it to

00:04

jump so high and it's really clever

00:07

because it solves a fundamental

00:09

limitation of animal muscles humans come

00:11

up against the same limitation but we

00:14

get around it with tools and actually

00:16

it's kind of two limitations I'm going

00:18

to show you how humans deal with the

00:20

problem first because it's quite

00:21

instructive and then we'll see how the

00:23

same mechanical principles are found

00:25

inside the grasshopper's body and a few

00:28

different variations in other animal so

00:30

here's a problem that a human might face

00:32

there's an object in the distance that I

00:33

would like to puncture a hole in and

00:36

I've got this little steel ball here so

00:39

I think if I can get the ball going fast

00:41

enough by the time it reaches that thing

00:43

maybe it'll puncture a hole in it and I

00:46

think well how can I do that I'm going

00:47

to throw it with my

00:51

arm the problem is the steel ball is

00:54

quite light which means it's not

00:55

offering much inertial resistance to my

00:58

muscles so my hand ends up traveling

01:01

really quickly and actually it takes

01:04

muscles a little bit of time to build up

01:07

to their maximum force and by the time

01:11

the ball has left my arm I'm nowhere

01:14

near my maximum Force that's the first

01:17

limitation of muscles and it's quite

01:19

easy to overcome actually in quite a

01:21

counterintuitive way and that is to just

01:24

make the ball heavier so this ball has

01:27

much more inertia so my arm is is going

01:30

to move more slowly when I throw it but

01:33

at least it's going to give my muscles a

01:35

chance to get up to maximum force and

01:38

because it's heavier it's going to have

01:39

more kinetic energy meaning when it hits

01:41

the target it's going to have more

01:43

puncturing ability but this is where we

01:45

come up against the big limitation of

01:48

muscles you can either apply a large

01:51

Force slowly or a small Force at high

01:55

speed and it's something you've

01:56

experienced like if you've ever lifted

01:58

weight if it feels heavy to you you have

02:01

to lift it slowly so that makes

02:02

intuitive sense but it also makes

02:04

mathematical sense because what you're

02:06

experiencing is your muscle maximum

02:09

power output like you know that power is

02:12

a measure of how quickly you can deliver

02:14

energy in other words energy divided by

02:17

time but maybe you also know that energy

02:19

is force times distance moved in

02:22

direction of force and if we slide

02:24

things around to get the force term on

02:26

its own you can now see that power is

02:29

also force times speed so given that

02:32

your muscles have a maximum power output

02:34

that explains why you can either have a

02:36

small force moving quickly or a large

02:38

force moving slowly but if I want either

02:40

of these balls to leave my hand with

02:44

enough speed to puncture the target when

02:46

it arrives I need to be applying a large

02:50

Force at high speed but with my muscles

02:53

I can't do both and that's where the use

02:55

of tools comes in the tool in this case

02:57

is a slingshot here in the UK we call it

02:59

a caterp but that's a bit confusing cuz

03:01

other things are called catapults so

03:02

I'll keep calling it a slingshot

03:03

probably the elastic of this thing is

03:05

really strong so to pull it back I have

03:07

to use a large Force which means I have

03:10

to move my muscle slowly but that's fine

03:12

because what I'm doing is I'm storing

03:15

all that energy as elastic potential

03:17

energy in the slingshot and the

03:21

slingshot doesn't have the same

03:22

limitations as my muscles it can move

03:25

with a large Force quickly

03:34

so a slingshot is an example of a

03:37

mechanical Power amplification device

03:40

and humans have invented loads of those

03:42

things another obvious example is a bow

03:44

and arrow I use a large Force traveling

03:47

slowly to flex the bow and that stores

03:51

energy again as elastic potential energy

03:55

and all that energy can be delivered by

03:57

the bow with a large Force quickly one

03:59

of my favorite examples is a barbecue

04:01

lighter inside there is a quartz crystal

04:05

and if you hit it really hard it'll

04:07

generate an electric spark these two

04:09

wires carry that electric spark up to

04:12

the tip where it can ignite a flame but

04:15

you would never be able to hit it hard

04:16

enough just like with moving your finger

04:18

that short distance so instead you apply

04:21

a large Force slowly right and that

04:23

compresses a spring so all that energy

04:26

is being stored in the spring and at

04:28

some point you get far enough down that

04:30

um catch is released and all the energy

04:33

that's stored in the spring is released

04:35

with a large Force

04:36

quickly and that's enough of a force

04:39

hitting the crystal to generate the

04:41

spark the hammer on a pistol works in

04:43

the same way as a barbecue lighter and

04:45

by the way in all these examples we're

04:46

never using an external source of energy

04:49

all the energy comes from your body it's

04:51

just stored slowly and released quickly

04:53

even the electrical energy in the spark

04:55

ultimately comes from your muscles so

04:57

that's what humans have figured out but

04:59

what about the gra Hopper is there

05:00

something like a slingshot or an archery

05:02

bow inside the grasshopper's body so

05:05

here's a diagram of the back leg of a

05:07

grasshopper and there are two tendons

05:09

the one shown in red extends the leg so

05:11

that's called the extensor tendon and

05:13

the blue one flexes the leg so that's

05:15

called the flexer tendon and of course

05:17

each tendon is pulled by a muscle and in

05:19

my model that's just these two ropes

05:21

here the flexer tendon in blue the

05:23

extensor tendon in red and you can see

05:25

it's just a lever that pivots around

05:27

this point this is the knee joint that

05:29

extensor muscle is big like amazingly in

05:32

a large grasshopper like a locust that

05:35

extensive muscle can produce almost 15

05:38

Newtons of force which means with both

05:41

back legs at the same time a grasshopper

05:44

could lift these three bags of sugar so

05:47

the peak force is huge but unfortunately

05:49

it takes a little while to reach Peak

05:51

Force about 300 millisecond which

05:54

doesn't sound like a lot but it only

05:56

takes 30 milliseconds for the

05:58

grasshopper to leave the ground once the

06:00

jump has started so by the time the peak

06:02

Force has reached there's nothing to

06:04

push against that's a bit like the issue

06:06

that I had with my tricep muscle and

06:08

then there's the big limitation of

06:10

maximum power that we talked about

06:12

earlier like a locust could bench press

06:14

3 Kg but it could only do it very very

06:17

slowly and that's no use for the jump so

06:19

the grasshopper needs something like a

06:21

bow something that can store energy and

06:23

release it quickly and this is actually

06:25

something that you can see from the

06:27

outside compare this jumping leg on the

06:30

left with this middle leg on the right

06:32

everything you can see here is

06:34

exoskeleton but the darker region is a

06:37

different type of exoskeleton it's much

06:40

stiffer much better for storing lots of

06:42

elastic energy and you can see in this

06:44

video how it bends before the kick a lot

06:47

of these videos and animations come from

06:48

Dr Bill heer's website by the way which

06:50

has been an amazing resource for this

06:52

video linking the description for that

06:54

so in our model we've added a spring to

06:57

represent that specialized exoskeleton I

06:59

also added this lever here that's not

07:02

part of the grasshopper's body that's

07:04

just there to give my puny muscles

07:07

enough mechanical advantage to be able

07:09

to represent the immense strength of the

07:12

grasshopper's extensor muscle so here's

07:15

the sequence first the flex attendant

07:17

pulls the leg up and it holds it there

07:20

so then when the extensor muscle

07:23

contracts it's not going to cause the

07:25

leg to kick out because it's being held

07:27

in place by the flexor muscle in instead

07:30

it's going to cause that spring to

07:32

contract which remember in the case of

07:34

the grasshopper is actually a super

07:36

stiff specialized bit of exoskeleton

07:39

that's going to bend like an Archer bow

07:41

and because it's so stiff the extensor

07:43

muscle has to apply a large Force which

07:46

means it has to move slowly and that's

07:49

absolutely fine because what it's doing

07:51

is storing up all that energy in the

07:54

spring then all the grasshopper has to

07:56

do is release the flexor muscle and all

07:59

that gets delivered with a large Force

08:02

quickly like that but that's not the

08:05

whole story because the flexor muscle is

08:08

much weaker than the extensor muscle

08:11

like the extensor muscle can produce up

08:13

to 15 Newtons of force but the flexor

08:16

muscle can produce up to like 0.7

08:19

Newtons of force so how is it that the

08:21

flexa muscle is able to hold the leg in

08:25

place against the much Superior force of

08:28

the extensor muscle that's acting to

08:30

oppose it well there's two things the

08:33

first is mechanical advantage you'll

08:35

notice that um the position of this

08:38

tendon is much further away from the

08:40

Pivot Point than this tendon here so

08:43

this has mechanical advantage over this

08:45

one but even that isn't enough there's

08:47

actually a little bump inside the knee

08:50

joint of the grasshopper and the flex

08:53

attendant goes around that bump so I've

08:56

put a rod here for the flex attendant to

08:58

go around so when the flexor tendon is

09:01

pulled and the leg reaches this position

09:03

you see how the tendon is leaving the

09:06

leg almost perpendicular so almost all

09:09

the force from the tendon is acting to

09:12

turn the leg around the pivot whereas if

09:15

you look at the angle of the extensor

09:18

tendon where it meets the leg it's a

09:20

shallower angle so it's only the

09:22

perpendicular component of that force

09:25

that acts to rotate the leg in the

09:28

opposite direction around the pivot

09:30

point and it's the combination of those

09:31

two factors that means the much weaker

09:34

flexer muscle is able to hold the leg in

09:37

place against a much stronger extensor

09:42

muscle there are loads of different

09:44

mechanical Power amplification

09:46

mechanisms found in nature and it's

09:48

really interesting to look at the

09:50

different types for example the frog

09:52

hopper it has one of the largest

09:54

accelerations in the animal kingdom

09:56

clocking in 500 G's it does that by

09:59

first pulling its leg up against its

10:01

chest right so imagine like the Frog

10:04

Hopper's body is up here this is the

10:06

chest and this is the leg that's coming

10:08

up and they stick together by something

10:12

akin to Velcro so I've put some velcro

10:14

there and then a muscle tries to pull

10:18

the leg free but it does it via some

10:20

kind of elastic thing like this so again

10:22

it's a large Force applied slowly energy

10:25

is being stored in that elastic medium

10:28

until eventually the dark C gives way

10:30

and all that energy is released with a

10:33

large Force quickly the human equivalent

10:35

might be something like a spud gun where

10:37

you build up energy until something

10:39

gives way in this case you're building

10:40

up pressure until the potato seal gives

10:43

way what about catch mechanisms do you

10:45

find those anywhere in nature like

10:47

humans use catches a lot to hold back a

10:50

large force with a catch that only

10:52

requires a small Force to release and it

10:55

turns out that the Trap jaw ant uses a

10:58

catch mechanism to to hold its jaw open

11:01

it then uses a large Force to slowly

11:03

build up energy behind the jaw and then

11:04

it uses a small Force to release the

11:07

catch so that the jaw snap shut on the

11:09

ant's prey this footage is from the ant

11:11

lab by the way link to their brilliant

11:13

video in the card and description so the

11:14

Trap jaw ant mechanism is not quite the

11:17

same as a crossbow in the sense that the

11:18

energy buildup stage happens after the

11:21

catch has been put in place it's a bit

11:23

like if the string of my crossbow was

11:25

slack when I locked it in place and only

11:27

then did I tighten up the string right

11:29

this is where I get distracted by a

11:31

massive side quest and I hope you'll

11:33

come with me cuz it's really interesting

11:34

so thinking about all these different

11:36

Power amplification mechanisms I thought

11:38

of one I was like I'm sure I've seen

11:41

this in a device before but I wonder if

11:43

it's ever happened in nature so I

11:45

printed this thing out to demonstrate it

11:48

gets harder and harder to open this

11:50

thing up as the elastic becomes more and

11:52

more stretched but actually Beyond a

11:54

certain point it gets easier again and

11:58

that's because of the shallow angle of

12:01

the elastic like only a small component

12:04

of the force from that elastic is

12:06

perpendicular to the arm so it gets

12:08

easier and easier and easier until look

12:12

when it passes the pivot point there

12:15

it's actually slightly holding it open

12:18

now and you only need a really small

12:20

Force to close it again I was sure that

12:24

I'd seen a mechanism like this in a

12:27

device but I just couldn't think where

12:29

it was which is very frustrating I even

12:32

built an alternative representation of

12:34

the thing so look this is a compliant

12:36

mechanism it's a by stable switch I

12:38

didn't Design This by the way and look

12:40

it switches between these two

12:43

configurations and you need a lot of

12:45

force to switch between the two stable

12:47

States but look if I get it just like

12:50

halfway between the two stable States

12:53

just as you're getting over that energy

12:55

hump you hardly need any Force at all to

12:58

move it around you know it's just as you

13:00

get over the hump and then it races away

13:03

to the other stable configuration but

13:05

what if you put a little nub in there

13:07

right so just as you're getting over the

13:09

energy hump the nub in's in the way so

13:12

you hardly need any Force at all to get

13:15

it back to that first stable

13:19

configuration and I'm pretty sure it's

13:21

the same kind of thing as this right you

13:23

get just past the energy hump you know

13:25

it gets easier and easier and easier you

13:27

get just past the hump and then it's

13:28

like on a a hair trigger but I still

13:32

couldn't think of any device that

13:33

employs this mechanism and then I spoke

13:35

to some people if you've got any ideas

13:37

please tell me because this video goes

13:39

out in two days uh lots of people had

13:43

ideas by the way tickets go on sale for

13:45

our end of year show in a few days I'll

13:47

link to that in the description a few

13:49

people said what about a mouse trap but

13:51

that's not quite the same mechanism like

13:54

when you're priming a mouse trap and

13:56

you're pulling that thing back it gets

13:57

harder and harder and harder harder and

13:59

harder all the way and then you apply a

14:02

catch to

14:04

it so it's not the same as this right

14:07

where it starts to get easier just at

14:09

the end there David didn't actually

14:11

suggested the lever Arch file just like

14:14

the thing that I demonstrated it's hard

14:17

to move at the beginning but look

14:20

eventually this is mostly moving side to

14:24

side so at that point you don't need

14:26

much force to move but you're not

14:29

working against this spring and it would

14:32

be easy to pop up if it wasn't for all

14:34

that

14:35

friction and it's easy to pop up Step

14:38

Smith mentioned these boom cards look

14:41

they pop up into a cube inside there's

14:43

an elastic band and when you get towards

14:46

flat there's pretty much no resistance

14:48

at all because the elastic band at that

14:50

point isn't really changing length but

14:52

there's enough bounce in the card to get

14:54

it started my favorite suggestion comes

14:56

from Matt barington the compound bow

14:59

actually gets easier to pull back Beyond

15:01

a certain point so it's easier to hold

15:04

in that drawn position compare that

15:06

experience to a normal bow where your

15:08

arm is quivering with the strain of

15:11

holding it at full draw that's a clever

15:13

idea isn't it so it turns out that

15:14

humans have used that mechanism a number

15:16

of times but I don't have an example of

15:19

it in nature if you can think of one let

15:21

me know you know it seems to me any way

15:23

you try to categorize the natural world

15:26

you'll always be able to find some

15:29

exception that defies your categorical

15:32

rule like the rule that mammals don't

15:34

lay eggs or fish don't fly or whatever

15:37

so I need to be careful because I've

15:40

kind of implied that humans always do

15:43

their power amplification through the

15:46

use of tools and animals always use

15:48

their bodies but actually I can think of

15:50

an exception to both of those rules like

15:53

take clicking your fingers for example

15:55

try and do that directly without par

15:57

amplification

15:59

it's a pretty weak sound what we

16:01

actually do is we press our thumb and

16:04

finger together and slowly build up

16:07

elastic energy in the muscles tendons

16:09

and joints and then we release it

16:11

quickly and you get that snapping of the

16:13

fingers there's only one known example

16:16

of an animal using something external to

16:19

its own body for mechanical Power

16:22

amplification and that's the slingshot

16:24

spider it stores elastic potential