The 5 weirdest science experiments of 2021

Every year scientists conduct truly bizarre experiments, and 2021 was no exception. From growing a mini-brain with its own eyes in petri dishes to resuscitating 24,000-year-old zombies from the permafrost and a few more of the year’s weirdest science experiments, Live Science magazine gathered together.

Artificial brain with eyes

In August, a team of scientists unveiled news that was both exciting and terrifying in equal measure. Researchers announced that they had successfully grown a tiny human brain with a pair of eyes in the lab. The scientists created a mini-brain by transforming stem cells into nerve tissue and then stimulating cell growth to form rudimentary “optic cups” filled with light-sensitive cells.

Fortunately, such organoids do not have enough neural density to gain consciousness. However, they are extremely useful for studying the stages of brain development and, potentially, for creating drugs for retinal diseases that cause blindness.

Ravens and the concept of zero

This year, scientists also conducted an experiment proving that crows are smart enough to understand the concept of zero. The concept of zero, supposedly created by human societies in the fifth century AD, requires abstract thinking. So it was quite a surprise when an article appeared in the June issue of the Journal of Neuroscience proving that crows distinguish zero from other numbers.

Scans of the birds’ brain activity during the experiments showed that crows had learned to understand zero numbers, but why they were able to do so remains a mystery. Scientists were amazed that both the human brain and the crow’s brain could calculate zero. This study proves that evolution may have taken different paths to create brains with the same higher-order functions.

Unraveling the “Brazil nut” phenomenon

In April, researchers finally found the answer to one of humanity’s most pressing questions: why, in a package of several kinds of nuts, Brazil nuts always end up on top. During the experiment, scientists shook a mixture of peanuts and Brazil nuts in a bag, taking three-dimensional X-ray scans of the bag after each shake. It turned out that successive shakes eventually flipped the larger nuts upright, after which each subsequent shake caused them to move upward. The scientists believe their study will help engineers develop better ways to prevent size dispersion in other mixtures, including those used in medicine and construction.

Turning water into metal

From ancient times until the 17th century, alchemists were obsessed with the Philosopher’s Stone: a mythical substance capable of turning lead into gold. In July, scientists reported an experiment that looks like the fulfillment of an alchemists’ dream: they were able to turn water into a shiny gold metal in just a few seconds. The researchers achieved this by mixing water with sodium and potassium. These metals give up extra electrons to water and consequently make water’s electrons roam freely, making it metallic. The “metallic water” created by scientists for a brief moment may give scientists the key to understanding what is under high pressure inside planets, where a similar process occurs naturally.

Living zombies from the permafrost

In June, the journal Current Biology published an article in which scientists described the process of reviving and cloning long-dead creatures from the Pleistocene permafrost. These “zombies” are multicellular microorganisms called bdelloid rotifers. After thawing, the tiny creatures began to reproduce asexually by parthenogenesis: creating exact clones of themselves. Remarkably, analysis of the soil around the creatures showed that they were frozen 24,000 years ago and survived by falling into cryptobiosis. Scientists hope to study this process to learn more about cryopreservation and how it can be adapted for humans.