Chartjunk. It took near-zero effort to find better ones all around this interesting and heavily researched topic, and their real papers too, per standard HN preference.
- https://www.zianet.com/wrucker/the%20energetic%20cost%20of%2...
- https://www.sciencedirect.com/science/article/pii/S258884042...
At a quick glance, none of those have a similar graph telling the same story: How efficient is it to get my own-self from A to B. A freight train sure moves a lot of mass, but how efficient is it for people-loads?
The first article comes close, but is more about why bicycles are so energy efficient (due to of all things not stretching your muscles!)
"near-zero", "all around"
I have questions.
Why have they animated the chart? It adds nothing, as far as I can tell.
Why all the tiny points? Is each one a data point (seems unlikely)?
Why is there only one swimmer?
Why is there a walker/runner area to the left and below swimmers? What is in that area?
Is this article just shilling for Big Velomobile? ;0)
Yeah I’m not sure why they picked these animals specifically. Seems like there would be some interesting data for big creatures (hippos, rhinos, elephants, whales), or unusually slow ones (tortoises, sloths).
Nothing on this chart surprises me, with the exception of salmon but that’s purely because I don’t really have any preconceptions about how efficient swimming is, beyond it feeling harder than walking in a human form.
Salmon is also a weird one to pick given their breeding method, you’d expect them to perhaps have some unusual adaptations as result of needing to swim hard upstream from time to time.
I was a bit surprised about the efficiency of swimming as well. Obviously, water has much higher viscosity than air. But, on the other side, pretty much 100% of the muscle movement can be translated into forward movement and no need to expend energy moving up and down against gravity. Also, a fish can glide a bit, unlike a walking animal (less than a bird, obviously).
Also the fastest fish (sailfish) is similar to the fastest land animal (cheetah) at somewhere around 110kmh.
FWIW, the original version of this chart is what Steve Jobs was referring to when he first used his “Bicycle for the Mind” analogy. There’s a clip of him talking about it somewhere on YouTube at an early computer fair.
Vulfpeck performing their song “Barbara” ft. clips of that Jobs interview:
Let’s not forget that you also need a paved road. The condor doesn’t need that.
Pure efficiency in locomotion is a terrible measure, is a person on a bicycle more efficient traversing a forest?
Trying to say that a dog is incredibly unefficient is misleading at best - especially when we're trying to make a statement about nature's most efficient traveller.
It's the classic physics issue - you are ignoring air resistance, but in this case you are ignoring everything other than a perfectly paved road.
> Pure efficiency in locomotion is a terrible measure, is a person on a bicycle more efficient traversing a forest?
Quite possibly. I would imagine it depends on the forest. I've been in forested areas on the mountain bike and you can cycle through these areas fine.
> It's the classic physics issue - you are ignoring air resistance, but in this case you are ignoring everything other than a perfectly paved road.
Rolling resistance is mainly down to the types of tyres used, how wide they are and how much they are inflated. Surface doesn't make that much of a difference IMO unless it is on a really lose surface e.g. loose gravel, mud or ice.
The biggest improvements to cycling efficiency is usually either being in a recumbent bicycle (less air resistance as you are led down) or by being in a more more Aero position with lycra on. But air resistance only becomes a big thing past 20mph or if you are wearing clothing that is really baggy.
Bicycles are the most efficient forms of transport in energy per mile. They are often the fastest in built up areas as well.
"Bicycles are the most efficient forms of transport in energy per mile. They are often the fastest in built up areas as well."
I don't disagree, but if this is the purpose of this graphic, why not just specifically measure different forms of transport in energy per mile?
This article is putting a metric of efficiency, while ignoring the reasons why things like a dog may have less efficent locomotion over perfectly flat terrain, because there are very few natural landmarks that have perfectly flat terrain.
I'd love to see a deeper comparison, how does efficiency of locomotion compare between animals within different types of environments, obstacles, etc. Otherwise this is a graphic that was used to make a point about cycling using an abstract measure rather than actual research.
They updated the graphic to include HPV style vehicles that are more aerodynamic than bicycles (usually just a bicycle with an aero-shell). I am not sure why this has come up now because I have an old bicycle book my Grandmother bought for me back in the late 90s that discusses these vehicles and it was known then they were more efficient.
> This article is putting a metric of efficiency, while ignoring the reasons why things like a dog may have less efficent locomotion over perfectly flat terrain, because there are very few natural landmarks that have perfectly flat terrain.
You can't control for this stuff and measure it really.
> I'd love to see a deeper comparison, how does efficiency of locomotion compare between animals within different types of environments, obstacles, etc.
Again this is difficult to control for. Other than particular areas where bicycle won't work (and there are very few places where that would apply), the bicycle is still likely to win out. Even if you have to get off occasionally to navigate over/under/around an obstacle you get all the benefits of efficiency for the majority of the time.
my intuition is that over smoothish, but hilly terrain, mountain bikes fare very well, too, since you get to go downhill for free. once you end up in a talus field, I think it becomes clear that "efficiency" is gone for basically any creature on land.
They aren't saying that dogs are incredibly inefficient – looks like dogs are right where they "should" be based on their body weight. The point of course stands that bikes need a flat ground to be efficient, but this isn't some sort of competition or measure of moral worth. It's just an observation that given that we've already filled human-inhabited spaces with nice flat surfaces, cycling happens to be a really efficient form of locomotion. Fish also need to be in water to be able to move at all, but that's immaterial for the purposes of the chart.
By extension, the electric bike is a very efficient way of transportation for those that don't like to do the manual work.
Agreed! And for older people, and those with injuries or minor disabilities that would otherwise require them to use a car. All in all, ebikes are a huge win! And likely to be one of the highest value outcomes of the ongoing electric transition.
Given all the means by which one might get from A to B, what is the most efficient. It might be that not all means are available, but the "pure efficiency" analysis allows you to answer that question from the means that are available.
Don't overthink it.
The average salmon weighs more than the average rat. Am I missing something?
> The average salmon weighs more than the average rat. Am I missing something?
an average rat typically weighs less than 1 pound, while an average salmon weighs several pounds.
Almost all game fish weight more than rats.
Do you live somewhere that game fish are particularly small, or rats are particularly large, or have you never been fishing?
I’m pretty sure they’re expressing confusion at the chart stating that salmon are lighter than rats.
I'm curious about why helicopters are located where they are. A powered sailplane case study: pipistrel snius weighs 700 lbs and gets 47 mpg. A comparable weight helicopter (mosquito XE) gets about 7 mpg.
That's the price you pay for not relying on airspeed to stay aloft.
Since it's a glider, did they incorporate the effects of thermals into the efficiency numbers? That would be a bit like comparing it to a sailing ship with a small external motor.
Which is like comparing a person on a bike to a leopard.
The numbers I saw would be dramatically higher if sampling in freefall. Methodologies aim to average out those effects. It's easy enough to lie with disingenuous comparisons. It just doesn't make sense that something that needs to spin large rotors at supersonic speeds is more efficient than something that spins much smaller rotors.
I don't think the average horse is heavier than the average cow.
What's the unlabeled yellow point?
The first illustration has no legend or explanation of what the axes are (if you scroll it, you can find it), but if you scroll down, you're going to see it again. A bit annoying ¯\_(ツ)_/¯
what's cool to see is that vehicles created by humans the most efficient of all
You can sail around the world without spending any fuel.
You will expend energy managing the sails. Quite a lot of energy if the ship in question is a tall ship.
To be fair, so can a jellyfish.
What about a bear on a bike?
Seeing how this is related to physics I'm surprised they left out the Spherical Cow [1] since it would probably score high marks when it comes to efficiency.
Ah. But sorry, no. It's straight from "how to lie with charts".
How much energy is it going to take a human to cross 40000 km (circumnavigate the Earth)? A human on a jet will require around 2 tons of fuel and around 40 hours of time (fuel economy of about 4L per 100km of flight).
A human on a bicycle will roughly take about a year of travel (assuming a fairly reasonable 150km a day). In other words, about 1/50-th of a productive human life needlessly wasted that could have been used to improve the world.
Carbon footprint in the US is about 20 tons per year per person, so that's another way to look at a year of missed opportunity that you would spend by cycling instead of flying.
This aspect is almost completely ignored when people talk about bikes or public transit. Yes, they are efficient, but their efficiency comes at a cost of several wasted lifetimes of time every day for a large city.
The paper looks at energy expenditure for the purposes of travel. Of _course_ slower methods are more efficient. They didn't include ICBMs but those would be crazy expensive.
That's it, that's the whole story. Adding calories for the "other stuff" that happens while travel is occurring is not part of the story.
Only if you think the journey doesn't contribute to the lifetime. Exercise is net beneficial and you meet nice people along the way.
Biking doesn't provide all the necessary exercise. It's better than doing nothing, but it also takes away time that can be spent on doing resistance training. That is far more important for bone density and muscle mass.
You can't evaluate bicycle's efficiency in the city only by looking at the rider's consumed energy. There's a lot of other things to it. In a modern city using a bike takes the same amount of time as using public transport. And you exercise while riding and you don't burn any additional energy and you take less space.
Those are valid points to make, but they don't relate to the figure. The chart should just show the raw naked numbers, and then we can layer our understanding on top of it. Something like, "so the chart says air travel is x times more efficient, but given how bad it is for the environment I think..."
If the chart is already a mish mash of numbers with someone's subjective opinions of the sort you mention then it's useless.
You can't redefine "efficiency" to mean whatever you want it to mean.
But then you also need to include the overhead of living in a city (more carbon emissions due to more complicated infrastructure). It rapidly becomes more complex than a calorie chart.
And the most efficient way overall? Working from home in suburbs that don't have transit.
Living in a city takes inherently less resources than living in the countryside. You don't need to commute far, your water, electricity, gas, savage, road, telecommunication etc infrastructure is shared by many more people per 1 mile. You get effects of scale for basically everything (from school and healthcare, through policing, administration, transportation, mail, deliveries, junk disposal).
If you live in apartment instead of detached house - even your AC/heating gets smaller because you get less external surface area per person.
Getting this wrong and thinking living in a city uses more resources per Capita shows some serious biases.
Ok, now for the people using motor vehicles instead of their own muscle power, account for the time wasted at the gym for the equivalent exercise. Or for time at the hospital, due to their sedentary lifestyle. Then account for the various types of pollution and destruction caused by motor vehicles.
Or, you know, just appreciate this 2D chart for the two dimensions of factual information it is able to convey effectively.
The time isn't wasted, it's saving you time in gym and hospital and prolonging your life.