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The Roundest Object Ever (and How It Will Change the World)

The world’s roundest object helps solve the longest running problem in measurement — how to define the kilogram. A kilogram isn’t what it used to be. Literally. The original name for it was the ‘grave’, proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK.

But the problem with this definition has long been apparent. The IPK doesn’t seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram’s dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance.

The Avogadro project aims to redefine Avogadro’s constant (currently defined by the kilogram — the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro’s constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro’s constant.

The Human Body (Paper Stop-Motion)

A handmade “demo video” for Tinybop’s Human Body App, which teaches kids about how body systems function.

All parts are made with paper—including the sounds.

Available on iTunes.

What Space Smells Like

According to many astronauts, space smells like metal and fuel. Other say they’ve picked up notes of grilled meats. When wondering about the smell of space, who better to consult than an astronaut?

Not that they’ve experienced it first hand, either — space is a vacuum, so they would be dead — but they have taken more than a whiff or two of the residue on their space suits.

It’s generally agreed that the aroma is slightly acrid, but not unpleasant. One space traveler even said the scent took him back to the summers of his youth when he worked as an arc welder.

The smell is mostly attributed to dying stars, traces of which are reportedly everywhere — comets, meteors, space dust — you name it. Not only does the aromatic byproduct of the explosions spread, it tends to linger.

The hydrocarbons responsible for the intensity and breadth of space’s olfactory signature are also found in terrestrial products like oil, coal, and some foods.

NASA has commissioned the replication of the smell, so someday we may all get a chance to breathe in some space splendor.

Physics [BBC Science Club]

Physics - Short animation, which was part of the Science Club series on BBC2 hosted by Dara O Briain

Directed by: Åsa Lucander
Art&Design: Åsa Lucander
Additional Art: Marc Moynihan
Stop Motion & Compositing: Julia Bartl
Animation: Kim Alexander, Marc Moynihan, Anna Fyda, Barry Evans, Lucy Izzard, Simon Testro, Phoebe Halstead, Michael Towers
Sound: Laura Coates
Produced by: 12foot6

What is Dyslexia?

Dyslexia affects up to 1 in 5 people, but the experience of dyslexia isn’t always the same.

This difficulty in processing language exists along a spectrum — one that doesn’t necessarily fit with labels like “normal” and “defective.” Kelli Sandman-Hurley urges us to think again about dyslexic brain function and to celebrate the neurodiversity of the human brain.

Lesson by Kelli Sandman-Hurley, animation by Marc Christoforidis.