Boyle's law

science & techWikipedia1662

Boyle's law

the gist

Boyle's law states that for a fixed amount of gas at constant temperature, pressure and volume are inversely proportional, so their product stays the same. Double the pressure and the gas takes up half the space. Robert Boyle published the law in 1662 after experiments with air pressure. In France it is often called Mariotte's law, after the physicist Edme Mariotte, who independently arrived at it.

how it works

Gas molecules constantly bump into the container walls and create pressure. Squeezing the gas into a smaller space makes these impacts more frequent, so the pressure rises in proportion as the volume falls.

so what

It is one of the first quantitative laws about gases and a foundation of later kinetic theory. It explains everyday things like how a syringe, a bicycle pump or a diving lung behaves when squeezed.

the bigger pattern

Boyle's law is one of the gas laws that were later combined into the ideal gas law, which links pressure, volume, temperature and amount of gas.

fun fact

In France the law is commonly called Mariotte's law, reflecting Edme Mariotte's independent work on it.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Illustrative photo · Reginaprice2013, CC BY-SA 3.0, via Wikimedia Commons

source: Wikipedia ↗

historyWikipediaclassic1336–1565 · Karnataka, India

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗