DeepSeek: DeepSeek V4 Flash 0731

DeepSeek · open source ★★★ original

Prompt: "Tell me something I don't know." Released: July 2026
DeepSeek: DeepSeek V4 Flash 0731
DeepSeek
July 2026
open source ★★★ original

Here are five facts that are likely to be entirely new to you, spanning different fields of science, history, and biology. I've aimed for the ones that are the most counterintuitive or that debunk common misconceptions.

1. The Amazon rainforest does not produce 20% of the world's oxygen (and never did).
You've probably heard this statistic your whole life. It's a myth. The Amazon produces about 6–9% of the oxygen in the atmosphere. The real oxygen powerhouse is the ocean—specifically, microscopic phytoplankton that produce between 50% and 80% of the Earth's oxygen. The "20% from the Amazon" figure was a misunderstanding of a 1980s study about how much oxygen is recycled by the forest, not produced for the atmosphere.

2. Sloths can hold their breath longer than dolphins.
Dolphins can stay submerged for about 10 to 15 minutes. Sloths—those famously slow, tree-dwelling mammals—can hold their breath for up to 40 minutes underwater. They achieve this by slowing their heart rate to one-third of its normal speed and shunting blood away from their limbs to their vital organs. They do this to cross rivers or escape predators, making them surprisingly adept swimmers.

3. You are technically "blind" every time you move your eyes.
This is called saccadic masking. When your eyes dart from one focal point to another (which happens several times per second), your brain actively blocks the visual signal from your retinas. This prevents you from seeing a blurry smear of motion. During those fractions of a second, you are completely blind, but your brain fills in the gaps with what it expects to see, so you never notice. It's the reason you don't see the world spinning when you look around.

4. The can opener was invented 48 years after the tin can.
The tin can was patented in 1810, but the first dedicated can opener wasn't invented until 1858. For nearly half a century, how did people open cans? They used a hammer and chisel, or sometimes a bayonet. The cans were so thick that the instructions on early cans literally said: "Cut round the top near the outer edge with a chisel and hammer." The modern rotating can opener didn't appear until 1870.

5. A "jiffy" is a real, measurable unit of time in physics.
In everyday language, a jiffy means "a moment." But in physics, a jiffy is a precise unit defined as the time it takes light to travel one centimeter in a vacuum. That works out to approximately 33.3564 picoseconds (or 0.000000000033 seconds). In electronics, a jiffy is also used to refer to the time between alternating current power cycles.


Did any of these surprise you, or did you already know one? If you knew all of them, I can dig even deeper!

3495 tokens 🦥 sloths
show reasoning
1. **Analyze the User's Request**: * Prompt: "Tell me something I don't know." * Intent: The user wants a surprising, obscure, counterintuitive, or highly interesting piece of trivia/fact that they likely haven't encountered before. * Constraint: It must be *something they don't know*. Since I don't know the user's exact knowledge base, I need to provide a fact that is statistically likely to be unknown to most people, highly engaging, and verifiable. 2. **Brainstorming Candidate Facts**: * *Fact 1*: Octopuses have three hearts, and two stop beating when they swim. (Too common). * *Fact 2*: Bananas are radioactive. (Too common). * *Fact 3*: A group of flamingos is called a "flamboyance". (Common). * *Fact 4*: Honey never spoils. (Common). * *Fact 5*: The Eiffel Tower can be 15 cm taller during the summer. (Common). * *Fact 6*: There are more possible iterations of a game of chess than there are atoms in the observable universe. (Common). * *Fact 7*: The "P" in "Pterodactyl" is silent. (Common). * *Fact 8*: *Something about the brain*: Your brain uses 20% of your body's oxygen. (Common). * *Fact 9*: *Something about history*: The shortest war in history was between Britain and Zanzibar in 1896, lasting 38 minutes. (A bit common, but good). * *Fact 10*: *Something about nature*: Cows have best friends and get stressed when separated. (Common). * *Fact 11*: *Something about physics/space*: A day on Venus is longer than a year on Venus. (Common). * *Fact 12*: *Something about the human body*: You are taller in the morning than at night. (Common). * *Fact 13*: *Something about animals*: A shrimp's heart is in its head. (Common). * *Fact 14*: *Something about trees*: There is a tree in India whose root system covers over 4 acres. (Interesting, but maybe known). * *Fact 15*: *Something about language*: The word "set" has the most definitions in the English language. (Common). * *Fact 16*: *Something about insects*: Dragonflies have a 95% hunting success rate. (Good, but maybe known). * *Fact 17*: *Something about geology*: The Earth's core is as hot as the surface of the sun. (Common). * *Fact 18*: *Something about dinosaurs*: Dinosaurs didn't roar; they likely cooed or grunted. (Good). * *Fact 19*: *Something about the ocean*: There are underwater rivers and waterfalls. (Good, but maybe known). * *Fact 20*: *Something about time*: A year on Mercury is 88 Earth days, but a *day* (solar) on Mercury is 176 Earth days. So a day is twice a year. (Good). * *Fact 21*: *Something about the human body*: The human stomach can dissolve razor blades (due to acid), but you shouldn't try it. (Good). * *Fact 22*: *Something about animals*: Squirrels plant thousands of trees every year by forgetting where they buried their acorns. (Common). * *Fact 23*: *Something about physics*: Light takes about 8 minutes to reach Earth from the Sun. (Common). * *Fact 24*: *Something about biology*: There are more bacteria in your body than human cells. (Common, but ratio changed recently, still bacteria outnumber in certain areas, but the 10:1 ratio is debunked. Let's avoid). * *Fact 25*: *Something about history*: The Great Pyramid of Giza was the tallest man-made structure for 3,800 years. (Common). * *Fact 26*: *Something about astronomy*: Neutron stars are so dense that a sugar-cube-sized amount would weigh about a billion tons. (Common). * *Fact 27*: *Something about psychology*: The "Mandela Effect" is a phenomenon where many people misremember facts. (Common). * *Fact 28*: *Something about animals*: A group of porcupines is called a "prickle". (Cute, but maybe known). * *Fact 29*: *Something about geography*: Russia has a border with North Korea. (Good, but maybe known). * *Fact 30*: *Something about human biology*: You are born with about 300 bones, but as an adult, you have 206, because some fuse together. (Common). * *Fact 31*: *Something about plants*: Bamboo can grow up to 35 inches in a single day. (Common). * *Fact 32*: *Something about sound*: The sound of a whip cracking is actually a tiny sonic boom. (Common). * *Fact 33*: *Something about chemistry*: Water expands when it freezes, which is why ice floats. (Common). * *Fact 34*: *Something about animals*: Octopuses have blue blood. (Common). * *Fact 35*: *Something about space*: The footprints on the Moon will stay there for millions of years because there is no wind or water to erode them. (Common). * *Fact 36*: *Something about history*: Cleopatra lived closer in time to the invention of the iPhone than to the building of the Great Pyramid. (Very common). * *Fact 37*: *Something about nature*: The Amazon rainforest produces 20% of the world's oxygen. (Debunked, actually it's about 6%, and the ocean produces most. Let's use the debunked one as a "something you don't know" - "The Amazon produces about 20% of the world's oxygen" is FALSE. The ocean produces most. That's a good myth-bust). * *Fact 38*: *Something about animals*: Sloths can hold their breath longer than dolphins. (Wait, dolphins hold for 10-15 mins, sloths for 40 mins underwater. This is a great obscure fact). Let's use this. * *Fact 39*: *Something about physics*: If you were to travel at the speed of light, time would stop for you. (Common). * *Fact 40*: *Something about biology*: The average person has about 60,000 miles of blood vessels in their body. (Common). 3. **Selecting the Best "Unknown" Facts**: * I need to pick a few that are *highly* obscure, counterintuitive, or debunked common myths. * *Candidate A*: Sloths can hold their breath for up to 40 minutes, longer than dolphins (which hold for about 10-15 minutes). This is surprising and not widely known. * *Candidate B*: The "Amazon produces 20% of oxygen" is a myth. The ocean produces about 50-80%. This corrects a common misconception. * *Candidate C*: The human body has enough iron to make a small nail, enough water to fill a bathtub, etc. (Common). * *Candidate D*: There is a species of jellyfish (*Turritopsis dohrnii*) that is biologically immortal. (Common). * *Candidate E*: The first "computer bug" was an actual moth found in a Harvard computer in 1947. (Common). * *Candidate F*: "Space smells like seared steak and hot metal" - according to astronauts. (Good). * *Candidate G*: The Earth is not a perfect sphere; it's an oblate spheroid (bulges at the equator). (Common). * *Candidate H*: A single bolt of lightning contains enough energy to toast 100,000 slices of bread. (Fun). * *Candidate I*: The "wow" signal from space was never explained. (Common). * *Candidate J*: The brain deletes the "unimportant" details of your vision, so you are technically "blind" for a fraction of a second when you move your eyes (saccadic masking). This is very cool and obscure. * *Candidate K*: The "thylacine" (Tasmanian tiger) had a pouch for both males and females. (Obscure). * *Candidate L*: The "G" in "G-string" doesn't stand for anything. It's just a letter. (Obscure but not scientific). * *Candidate M*: The "Loch Ness Monster" was once a circus elephant story? No. * *Candidate N*: The "Okapi" is the closest living relative to the giraffe, but has zebra-like stripes. (Common). * *Candidate O*: The "P" in "Pterodactyl" is silent. (Common). * *Candidate P*: A "jiffy" is an actual unit of time in physics (10^-44 seconds). (Good). * *Candidate Q*: The "smell of rain" (petrichor) is caused by bacteria (actinobacteria) releasing geosmin. (Good, but slightly common now). * *Candidate R*: The "can opener" was invented 48 years after the tin can. (Good). * *Candidate S*: The "blue whale's" heart is so big that a human can swim through its arteries. (Common). * *Candidate T*: The "speed of a sneeze" is 100 mph. (Common). 4. **Structuring the Response**: * Since the prompt is open-ended, I will provide a curated list of 3-5 facts that are highly likely to be new to the user, covering different domains (biology, physics, history, debunked myths). * I will make sure to explain *why* they are surprising or obscure. * Let's pick the absolute best ones: * **Fact 1 (Debunked Myth)**: The Amazon rainforest does *not* produce 20% of the world's oxygen. It produces about 6%, and the ocean's phytoplankton produce about 50-80%. This is a great "something you don't know" because most people *think* they know it. * **Fact 2 (Biology)**: Sloths can hold their breath for up to 40 minutes underwater, which is longer than dolphins (which typically hold for 10-15 minutes). This is a wild counterintuitive fact. * **Fact 3 (Physics)**: A "jiffy" is a real unit of time in physics, equal to the time it takes light to travel one centimeter (about 33.3 picoseconds). Also, in electronics, it's the time between alternating current cycles. * **Fact 4 (Human Biology)**: Your eyes perform "saccadic masking". When you move your eyes, your brain actively blocks the visual signal, so you are technically blind for a fraction of a second during every eye movement. You never notice because your brain fills in the gaps. * **Fact 5 (History/Technology)**: The can opener was invented 48 years *after* the tin can was patented. The first cans were opened with a hammer and chisel. 5. **Refining the Chosen Facts**: * Fact 1: Amazon oxygen - Confirm the correct percentage. The ocean produces ~50-80% of oxygen, Amazon produces about 6-9%. Good. * Fact 2: Sloth breath-holding - Confirm. Yes, sloths can slow their heart rate and hold breath for up to 40 minutes. Dolphins hold for about 10-15 minutes. Great. * Fact 3: Jiffy - Confirm. In physics, a jiffy is the time taken for light to travel 1 centimeter (approx 33.3564 picoseconds). Good. * Fact 4: Saccadic masking - Confirm. Yes, this is a neurological phenomenon. Good. * Fact 5: Can opener - Confirm. The tin can was patented in 1810. The can opener was invented in 1858. 48 years. Good. 6. **Final Polish**: * Write in a friendly, engaging tone. * Clearly separate each fact. * Add a concluding line to invite them to ask for more if they knew all of these already.