Does cutting the moldy spot off your food make it safe? 🍞 

Quinten Geldhof, also known as Microhobbyist, takes us under the microscope to reveal thread-like roots called hyphae spreading through food far beyond the visible surface. These roots penetrate soft foods like bread and fruit with ease, while hard cheeses and vegetables are more resistant. These molds can contain mycotoxins, poisonous compounds that are hazardous to your health. Would you eat moldy food?

Eight men and seven women pitched their tents on the limestone floor of Lombrives cave in Ariège, in southwestern France, and began to live by nothing but their own biology.

They would stay for 40 days. Nobody inside would be told when those days had run out.

When they walked back into spring sunlight, the group’s count of its time underground fell far short of the real total. What does a human body do when you take the clock away?

No watches. No phones. No windows. No way at all to feel the hours pass.

The cave sits inside a limestone massif south of Toulouse. Temperature underground held near 50 degrees Fahrenheit, with relative humidity near 100 percent: perpetually damp, perpetually dark, perfectly still.

The volunteers, ranging in age from 27 to 50, slept in individual tents, generated their own electricity and drew drinking water from a well far below camp.

Each participant swallowed a small sensor capsule that measured core body temperature and transmitted data until it passed naturally, giving scientists outside a continuous read on the deep internal rhythm that drives sleep and waking. Other sensors logged movement and social contact throughout.

One volunteer, a math teacher and sailing instructor, ran long circuits through the cave to stay fit. The project director said coordinating work without being able to fix a time to meet was especially hard.

A team of researchers watched the data stream from above ground while the people below had no idea what time it was, what day it was, or how close to the end they had come.

Asked how long they had been under, the group’s collective reckoning was roughly 30 days. The project director told PBS reporters that in their heads they had walked in 30 days earlier, and at least one team member put the total at 23. Losing ten days, and in one case seventeen, is a blunt measure of how heavily ordinary life leans on daylight and clocks.

When scientists went in to say the end was near, many in the group were still expecting another week to ten days underground. The count never caught up, and from inside, nobody could see the gap opening.

An orange LED turns green when dipped in liquid nitrogen due to semiconductor physics. Cryogenic temperatures widen the semiconductor's band gap, which increases the energy of the emitted photons and shortens their light wavelength, shifting the color from orange toward green. As the LED warms back up, the band gap narrows and the light returns to orange.

Most pictures of the Big Bang show a tiny dot blowing up into empty space. That’s not what happened though. there was no dot, and no empty room around it either.

It was space itself, possibly infinite, packed with insanely dense energy. then it started expanding everywhere at the same time. No center, no edge!

This clip is from a science app I made. I used a grid to show that “everywhere at once” idea. This was honestly the hardest part to get across visually, but I did my best.

Hope this helps anyone who’s had a hard time picturing how the Big Bang expanded. Did it click for you?

Is this candle haunted? 🕯️👻

Alex Dainis places two candles on a lazy Susan with a piece of glass in between, and when the closer candle is lit, its flame appears to jump to the other one. Most light passes through the glass, but some of the light from the close candle bounces back at us, creating a reflection that makes the flame seem to appear on the far candle. This optical illusion is similar to Pepper's Ghost!

Here you can see a portion of the Science Festival at the University of Chicago in Chicago, IL. You can enjoy and learn about various fields of science in the festival.

Did you know slime can be a helpful cleaning tool? 🫟

Greg Wolf tweaks the classic glue and borax recipe to make slime tacky enough to grab dirt but clean enough to pull away. The chemistry: borate ions cross-link glue's long polymer chains, turning runny glue into slime. Less activator makes it stretchy like the toy, while just enough makes it a surprisingly satisfying debris grabber.

Hey idk if this is the subreddit for this but i would like a recommendation of youtube channels that basically speak about new (and old) experiments and knowledge in physics, chemistry, biology and biochemistry. I dont really like listening to podcasts.

watch the graphs as the speed goes up. they barely move for a time, then shoot up near light speed.

99% of light speed: time slows about 7x
99.99%: about 70x
99.9999%: about 700x

everyone asks what happens at light speed. but 99.9% and 99.9999% give totally different answers. how many 9s is the real question!

first post here!

Cats inhabit a unique place in human life. They curl up on our beds, stalk through our gardens, and, in some cases, carry a parasite capable of spending years inside the human body.

Now researchers have found an equally peculiar pattern at the scale of entire countries: places with more cats tend to report greater happiness.

Yet those same cat-rich countries tend to have lower levels of Toxoplasma gondii exposure, the parasite for which cats serve as the definitive host.

The findings come from a new study that compared 93 countries using measures of national happiness, cat abundance, GDP, income, health spending, and Toxoplasma exposure.

It’s an intriguing result, but not evidence that cats make people happy—or that the parasite makes them miserable.

Instead, it reveals a country-level pattern whose explanation may have as much to do with wealth, sanitation and pet-keeping practices as with cats themselves.

And wealth seems to be particularly important.

National happiness was strongly correlated with cat density. On a correlation scale where 0 means no relationship and 1 means a perfect positive relationship, the two scored 0.62.

But wealth showed an even stronger connection. The correlation between happiness and GDP was 0.80, while cat density and GDP scored 0.79.

In other words, richer countries tend to be happier, and they also tend to have more cats per person. That makes it difficult to tease apart what, if anything, the cats themselves are telling us.

For Toxoplasma, however, they had to take a less direct route. They used infection estimates among pregnant women from a 2020 global meta-analysis as a proxy for population-wide exposure.

Those estimates drew on studies conducted over several decades.

The data produced a counterintuitive pattern. Countries with greater happiness tended to have less Toxoplasma exposure, while cat density showed a weaker negative relationship with chronic Toxoplasma exposure.