Neanderthals were using chemical reaction to light fire

Although the idea that Neanderthals knew how to use the fire was largely accepter, it was not clear if they were able to turn it on or they used the natural flames, such as those produced by lightning.
To shed light on the issue, a study published in Scientific reports that they analyzed the findings of blocks of manganese dioxide at the excavations of Pech-de-l’Azé I, in southwestern France. Where excavations, which are dating back to 50,000 years ago, are showing traces of Neanderthal. So far the best hypothesis about the discovery of these blocks of manganese dioxide was that it was used by Homo neanderthalensis as a kind of trick, or rather as a pigment to decorate the body.

What might suggest that Neanderthals were able to start the fire, from scratch, using nothing less than some chemistry is some archaeological evidence about the presence of powder of manganese dioxide in hearths. Also considering that to decorate their body, the coal fire was more available and easily accessible than manganese dioxide, which is preferred to other manganese oxides.

The researchers notes that “the combustion and thermogravimetric measurements show that the manganese dioxide reduces the self-ignition temperature of the wood, and substantially increases the coal combustion capability, suggesting that the most appropriate use of this substance was inn fact to produce fire”.

Practically, the Neanderthals could have treated the wood with this substance to start the fire, because it was easier. The more we know them, the more the stereotype of rough and undeveloped Neanderthals appear to be wrong.

Source: Come i Neanderthal sfruttavano la chimica per accendere il fuoco – Wired

Roman concrete is stronger than nowadays concrete

colloseum

The Pantheon: From Antiquity to the Present
We tend to believe that our ancestors were using archaic technologies, using either rocks or poor quality materials. This is certainly true for common people houses but most of the civilization let us incredible construction which are able to last for millennial. Romans are not the least: their most famous buildings are probably the Pantheon and Colosseum in Rome. It might be less famous that they’ve been using concrete to build it!

Yes, concrete, the mainstay of modern buildings. This composite material, made from cement mixed with sand and gravel, can be into whatever structure is required. Romans had a special ingredient to add in the mixture: fine volcanic ash, mixed with lime (calcium hydroxide) to make cement. The result is an alloy made of a network of crystals that resist propagation of cracks (the weakness of modern concrete), and is an incredibly enduring material that is superior to today’s concrete! A testament to this is the majestic roof of the Pantheon, which, at 43 meters across, is still the world’s largest unenforced concrete dome. Want to know the best? It is today’s even stronger than when it was built!

Internal_Pantheon_Light
The Pantheon: Design, Meaning, and Progeny, With a New Foreword by John Pinto, Second Edition