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A feed that leaves you knowing more.

Wunderfeed is a swipe feed of short discoveries: why a mantis shrimp with twelve color receptors is bad at telling colors apart, how a slime mould with no brain drew a network like Tokyo's railways. Each takes about a minute. Every claim has a source.

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German & English

The two large, striped compound eyes of a mantis shrimp against a black background

A Greenland shark gliding just above the seafloor

Scroll inside the phone, or click itTap the phone for the next one

From the catalog

Not the usual trivia.

Less “did you know”, more “so that’s why”. Every discovery explains a mechanism, a measurement or a story: from studies published this year to old myths that finally get a proper answer.

Photo: Mikael Häggström
✦ New researchScience Advances · April 2025
Nº 048 · Perception · 55 sec
Five people have seen a color that doesn't exist in nature
A laser at Berkeley stimulated just one type of cone cell. The result was "olo": a blue-green more saturated than any color in nature.
Guess first
Photo: National Institute of Standards and Technology
Nº 064 · Technology · 50 sec
The kilogram prototype got lighter – or all its copies got heavier
For 130 years, a metal cylinder near Paris was by definition exactly one kilogram. That was precisely the problem.
Show me
3–5
failed dodges are enough to learn
Quick & curious · Nature
Jellyfish learn without a central brain.
After a few collisions, they kept further away from obstacles. Learning happens in their sensory clubs.
Photo: Jan Bielecki
Photo: This image was taken by the NASA Expedition 20 crew.
Nº 056 · History · 50 sec
What does a volcanic eruption have to do with Frankenstein?
In 1815, Tambora explodes in Indonesia. A year later, an 18-year-old is stuck in endless rain on Lake Geneva – and invents a monster.
Show me
89%
of red blood cells end up in the liver
Quick & curious · Nature
Glass frogs hide their red blood cells.
At rest they store almost 90 percent of their red blood cells in their liver, becoming more transparent.
Photo: Geoff Gallice from Gainesville, FL, USA
Photo: Dietmar Rabich
Nº 062 · Numbers · 50 sec
A sheet of paper all the way to the Moon?
A sheet is 0.1 mm thick, the Moon about 384,400 km away. The answer sounds like a miscalculation.
Guess first
Photo: Lance Vanlewen
Nº 014 · Physics · 1 min
How heavy is a cloud?
It floats above you. How much water does a cumulus cloud of one cubic kilometre hold?
Guess first
0.69g/cm³
average density (water: 1)
Quick & curious · Space
Saturn would float in water.
Its average density is lower than water's. A suitable bathtub would have to be enormous.
Photo: NASA/JPL/Space Science Institute
Photo: Yathin S Krishnappa
Nº 039 · Nature · 50 sec
Why does the zebra have stripes?
Camouflage? Cooling? An experiment with striped horse blankets gives a surprising answer.
Guess first
Photo: Cahyo
✦ New researchNature · January 2026
Nº 051 · History · 55 sec
The oldest dated cave art is a hand – at least 67,800 years old
A faded patch of paint on an island off Sulawesi beats the previous record. It was dated with a clock that ticks inside crusts of calcite.
Show me
Photo: Charles J. Sharp
Nº 007 · Nature · 45 sec
Why does the wombat make cube-shaped poop?
A round gut shapes cubes. Researchers only recently worked out how.
Show me
Photo: flowcomm
✦ New researchNature Ecology & Evolution · June 2024
Nº 041 · Nature · 50 sec
Do elephants call each other by name?
Researchers had software analyse elephant calls – then played the animals what seemed to be their own names.
Show me

Photos from Wikimedia Commons and public archives. The photographer is named on every card. All image credits

New in the app

This week, only in the app.

Fresh discoveries go to the app first. A week later they get a page here.

Here from October 13
Nº 076 · History
When Oregon blew up a dead whale with dynamite
In 1970 half a ton of explosives was meant to turn a beached sperm whale into bite-sized pieces for seagulls. It went differently.
Here from October 13
Nº 075 · History
When Australia's army lost to emus
In 1932 soldiers with machine guns went out against emus raiding wheat fields. The birds proved hard to kill.
Here from October 13
Nº 074 · Space
A comet from outside our solar system.
3I/ATLAS was discovered in July 2025 – only the third known visitor from another star system. It's just passing through.

Recently added

Read on the web.

All discoveries

Nº 068 · Numbers · 50 sec
Switch or stay? The door puzzle that had mathematicians arguing
Three doors, one car, two goats – and a correct answer that drew some 10,000 letters in 1990.
Nº 067 · Body · 50 sec
Gut-lining cells live for days, the neurons in your cortex for a lifetime
There is no brand-new body every seven years. Ironically, carbon from atomic bomb tests gave the game away.
+ Deep dive
Nº 066 · Nature · 50 sec
A brainless slime mould designed a network like Tokyo's railways
Oat flakes were laid out like the cities around Tokyo. After about a day, a yellow single cell had linked them – much like the real rail network.
Nº 065 · Nature
Bacteria conduct electricity in the seafloor.
Cable bacteria transport electrons through long threads. Conducting fibres inside contain nickel proteins.
Nº 064 · Technology · 50 sec
The kilogram prototype got lighter – or all its copies got heavier
For 130 years, a metal cylinder near Paris was by definition exactly one kilogram. That was precisely the problem.
Nº 063 · Numbers · 50 sec
Why do so many numbers start with a 1?
In real-world data, a 1 comes first more than six times as often as a 9. Tax investigators use that.

How it works

Swipe up for the next one. Sideways to go deeper.

Up
Next discovery
Every swipe brings something new, mixed across topics and never the same category twice in a row.
Sideways
The why
A few short pages explain it: one thought per page, with the numbers that matter.
Tap
Guess first
Many discoveries open with a question. Make your guess, then see how it really is.

Try it here

From Nº 016 · Physics

Does time pass faster on a mountain?

Yes. Measurably so even a few stair steps higher – and your phone accounts for it every day.

Your guess

Where does a clock tick faster?

Sources

Sourced, not made up.

Every statement is tied to a verbatim quote from its source. Before anything is published, a script finds each quote again in the original, and a person reviews the whole discovery.

In the app

In 2010 researchers at the US institute NIST compared two extremely precise atomic clocks, one of them 33 centimeters higher. The upper one ran faster.

In the source
“…physicists at the National Institute of Standards and Technology (NIST) have measured this effect at a more down-to-earth scale of 33 centimeters”
NISTNIST Pair of Aluminum Atomic Clocks Reveal Einstein's Relativity at a Personal Scale

This discovery: 35 statements, 7 sources.

01
Verbatim
Each statement carries the quote that backs it. No quote, no statement.
02
Simplifications are named
Where a story has to simplify, a note says so, along with what researchers still argue about.
03
New research, labelled
Fresh studies carry a “New research” badge with journal and date, so you know how new it really is.
04
Free images, with names
Photos come with photographer and license. Illustrations are marked as illustrations.

Topics

From neutron stars to wombat droppings.

Pick what interests you and you’ll see more of it. Other topics still appear: curiosity needs surprises.

Space
Moon, sun, planets
“Why is a day on Venus longer than its year?”
Nature
Animals, plants, deep time
“Why is a mushroom more closely related to you than to a plant?”
Perception
How your brain sees
“There's a hole in your field of view.”
Numbers
Chance, maths, mind traps
“Switch or stay? The door puzzle that had mathematicians arguing”
Physics
Everyday life, seen anew
“Why does metal feel colder than wood?”
Body
What happens inside you
“Do you taste sweet only with the tip of your tongue?”
History
Time in perspective
“Cleopatra lived closer to the Moon landing than to the building of the pyramid”
Technology
How things work
“The first computer bug was a real moth”

Pace

A feed with an end.

After five discoveries the feed pauses and asks which one stays with you. You can keep going, but you don’t have to.

Your collection

Save what you want to keep. Everything is stored only on your iPhone.

Remember this?

How many folds until the stack reaches the Moon?

Days later a question about something you read comes back: after 2 days, then 4, then 8. Got it wrong? It’s back tomorrow.

Read
Day 2
Day 4
Day 8
Day 16

The deal

Free.
No ads.
No account.
No tracking.

Wunderfeed doesn’t know who you are. Interests, saved discoveries and progress stay on your iPhone; the app only downloads articles.

FAQ

Questions

What does it cost?

Nothing. Wunderfeed is free and has no ads.

Where do the discoveries come from?

From original sources: research papers, institutes, museums, space agencies and reference works. Every discovery lists its sources and image credits; tap the book icon on any card.

Is it written by AI?

AI helps with research and drafting behind the scenes. Every statement is then checked against its source, and a person reviews each discovery before it is published. No AI runs while you read: what you see is finished, checked content.

Do I need an account?

No. There’s no sign-up and no login. Everything the app remembers stays on your iPhone.

Which devices does it run on?

iPhone with iOS 26 or later.

Which languages?

German and English. The app follows your iPhone’s language; you can switch it per app in the iOS Settings.

How often is there something new?

New discoveries arrive without an app update, as soon as they are researched and checked. The feed is never padded with repeats.

I found a mistake.

Thank you! Please write to hello@deckle.io. Every discovery shows its sources, so you can check for yourself too.

wunderfeed

Scroll into wonder.

Short, sourced discoveries for iPhone.

Coming soon on theApp Store

A feed that leaves you knowing more.

12 color receptors – and still bad at seeing colors?

Greenland sharks can live for over 270 years.

Bogong moths find their way by the stars

Male seahorses get pregnant.

A brainless slime mould designed a network like Tokyo's railways

Five discoveries. Which one stays with you?

Not the usual trivia.

Five people have seen a color that doesn't exist in nature

The kilogram prototype got lighter – or all its copies got heavier

Jellyfish learn without a central brain.

What does a volcanic eruption have to do with Frankenstein?

Glass frogs hide their red blood cells.

A sheet of paper all the way to the Moon?

How heavy is a cloud?

Saturn would float in water.

Why does the zebra have stripes?

The oldest dated cave art is a hand – at least 67,800 years old

Why does the wombat make cube-shaped poop?

Do elephants call each other by name?

This week, only in the app.

When Oregon blew up a dead whale with dynamite

When Australia's army lost to emus

A comet from outside our solar system.

Read on the web.

Switch or stay? The door puzzle that had mathematicians arguing

Gut-lining cells live for days, the neurons in your cortex for a lifetime

A brainless slime mould designed a network like Tokyo's railways

Bacteria conduct electricity in the seafloor.

The kilogram prototype got lighter – or all its copies got heavier

Why do so many numbers start with a 1?

Swipe up for the next one. Sideways to go deeper.

Next discovery

The why

Guess first

Where does a clock tick faster?

One stair step is enough

And on Everest?

Your phone accounts for it

Sourced, not made up.

Verbatim

Simplifications are named

New research, labelled

Free images, with names

From neutron stars to wombat droppings.

Space

Nature

Perception

Numbers

Physics

Body

History

Technology

A feed with an end.

Your collection

Questions

Scroll into wonder.