The Science Book

DK

8 annotations • data

First annotation on Jul 18th, 2025.

Chapter 5

The Law of Definite Proportions, published by French chemist Joseph Proust in 1794, shows that no matter how elements combine, the proportions of each element in a compound are always precisely the same. This theory was one of the fundamental ideas about elements that emerged at this period to form the basis of modern chemistry.
If the same metal combined with oxygen in a different proportion, it formed a different compound with different properties.

Chapter 8

If light were streams of particles, as Newton said, there should simply have been a strip of light directly beyond each slit. Instead, Young saw alternating bright and dark bands, like a fuzzy bar code. He argued that as light waves spread out beyond the slits, they interact. If two waves ripple up (peak) or down (trough) at the same time, they make a wave twice as big (constructive interference)—creating the bright bands. If one wave ripples up as the other ripples down, they cancel each other out (destructive interference)—creating the dark bands. Young also showed that different colors of light create different interference patterns. This demonstrated that the color of light depends on its wavelength. For a century, Young's double-slit experiment convinced scientists that light is a wave, not a particle. Then in 1905, Albert Einstein showed that light also behaves as if it were a stream of particles—it can behave like a wave and a particle.

Chapter 9

In the Analytical Engine, Babbage hoped to create a machine that could "eat its own tail," meaning that it could use the results of its calculations to determine its next steps. This deceptively simple-sounding ability would allow it to perform any calculation imaginable; a fundamental feature of computers today, at the time it was a profound leap forward. The Analytical Engine was, therefore, a general-purpose computer that could be considered Turing Complete.
Lovelace combined mathematical rigor with a brilliant imagination that allowed her to see the potential of the machine beyond calculation, suggesting that it might even be able to "compose elaborate and scientific pieces of music of any degree of complexity." She wrote extensive notes based on Menabrea's paper, including an algorithm that would use the machine to calculate Bernoulli numbers. This algorithm is now recognized as the first complete computer program.
Observers already knew that in tropical hurricanes, for example, the winds blow in a circular or "cyclonic" pattern around a central area of low air pressure or "depression." It was soon realized that most of the large storms that blow in the mid-latitudes show this cyclonic depression shape. So the direction of the wind gives a clue as to whether the storm is approaching or receding.
Before FitzRoy began his weather reporting systems, mariners had already observed that winds form cyclonic patterns in hurricanes, and that wind direction could be used to predict the storm's path.
FitzRoy understood that the keys to weather prediction were systematic observations of air pressure, temperature, and wind speed and direction taken at set times from widely spread locations. When these observations were sent instantly by telegraph to his coordinating office in London, he could build up a picture or "synopsis" of weather conditions over a vast area.