Pratique du Shadowing: Where does gold come from? - David Lunney - Apprendre l'anglais à l'oral avec YouTube

C2
In medieval times, alchemists tried to achieve the seemingly impossible.
⏸ En pause
33 phrases
Si les phrases sont trop courtes ou trop longues, cliquez sur Edit pour les ajuster.
1
In medieval times, alchemists tried to achieve the seemingly impossible.
2
They wanted to transform lowly lead into gleaming gold.
3
History portrays these people as aged eccentrics, but if only they'd known that their dreams were actually achievable.
4
Indeed, today we can manufacture gold on Earth thanks to modern inventions that those medieval alchemists missed by a few centuries.
5
But to understand how this precious metal became embedded in our planet to start with, we have to gaze upwards at the stars.
6
Gold is extraterrestrial.
7
Instead of arising from the planet's rocky crust, it was actually cooked up in space and is present on Earth because of cataclysmic stellar explosions called supernovae.
8
Stars are mostly made up of hydrogen, the simplest and lightest element.
9
The enormous gravitational pressure of so much material compresses and triggers nuclear fusion in the star's core.
10
This process releases energy from the hydrogen, making the star shine.
11
Over many millions of years, fusion transforms hydrogen into heavier elements: helium, carbon, and oxygen, burning subsequent elements faster and faster to reach iron and nickel.
12
However, at that point nuclear fusion no longer releases enough energy, and the pressure from the core peters out.
13
The outer layers collapse into the center, and bouncing back from this sudden injection of energy, the star explodes forming a supernova.
14
The extreme pressure of a collapsing star is so high, that subatomic protons and electrons are forced together in the core, forming neutrons.
15
Neutrons have no repelling electric charge so they're easily captured by the iron group elements.
16
Multiple neutron captures enable the formation of heavier elements that a star under normal circumstances can't form, from silver to gold, past lead and on to uranium.
17
In extreme contrast to the million year transformation of hydrogen to helium, the creation of the heaviest elements in a supernova takes place in only seconds.
18
But what becomes of the gold after the explosion?
19
The expanding supernova shockwave propels its elemental debris through the interstellar medium, triggering a swirling dance of gas and dust that condenses into new stars and planets.
20
Earth's gold was likely delivered this way before being kneaded into veins by geothermal activity.
21
Billions of years later, we now extract this precious product by mining it, an expensive process that's compounded by gold's rarity.
22
In fact, all of the gold that we've mined in history could be piled into just three Olympic-size swimming pools, although this represents a lot of mass because gold is about 20 times denser than water.
23
So, can we produce more of this coveted commodity?
24
Actually, yes.
25
Using particle accelerators, we can mimic the complex nuclear reactions that create gold in stars.
26
But these machines can only construct gold atom by atom.
27
So it would take almost the age of the universe to produce one gram at a cost vastly exceeding the current value of gold.
28
So that's not a very good solution.
29
But if we were to reach a hypothetical point where we'd mined all of the Earth's buried gold, there are other places we could look.
30
The ocean holds an estimated 20 million tons of dissolved gold but at extremely miniscule concentrations making its recovery too costly at present.
31
Perhaps one day, we'll see gold rushes to tap the mineral wealth of the other planets of our solar system.
32
And who knows?
33
Maybe some future supernova will occur close enough to shower us with its treasure and hopefully not eradicate all life on Earth in the process.

Télécharger l'application

Notation IA pour chaque phrase que vous prononcez

Scanner pour télécharger
Scanner pour télécharger
Download on theApp Store
Get it onGoogle Play
TRENDING

Populaires

Context & Background

In the informative video "Where does gold come from?" by David Lunney, viewers are taken on a fascinating journey through the origins of gold, tracing its celestial beginnings. The speaker discusses how medieval alchemists dreamt of transforming lead into gold, unaware that modern science has unlocked the secrets behind this transformation. Gold is revealed to be a product of supernovae, the explosive deaths of stars, showcasing the intersection of astronomy and geology. This captivating narrative not only provides insight into the scientific processes that create gold but also serves as an engaging context for English language learners. Understanding such complex topics can greatly enrich vocabulary and comprehension skills during english speaking practice.

Top 5 Phrases for Daily Communication

  • "Cataclysmic stellar explosions" - Great for discussing astronomical events.
  • "Nuclear fusion" - Useful in conversations about energy and science.
  • "The expanding supernova shockwave" - A vivid description great for storytelling.
  • "Billions of years later" - Helps in discussing timelines in both history and science.
  • "Mined from the Earth" - Perfect for conversations about geology and natural resources.

Step-by-step Shadowing Guide

To effectively utilize the video for shadow speech and enhance your english pronunciation, follow these steps:

  1. Watch and Listen: Play the video at a comfortable speed, focusing on the natural rhythm and intonation of David Lunney's voice.
  2. Pause and Repeat: Rewind to sections that resonate with you. Try pausing after a sentence and echoing what you've heard. This technique is known as shadowspeaks.
  3. Break It Down: If you find certain phrases challenging, break them into smaller parts. Repeat these segments until you feel confident in your pronunciation.
  4. Practice with Intention: Focus on the top phrases identified. Use them in daily conversations to reinforce your learning and build confidence in english speaking practice.
  5. Record Yourself: Record your shadowing attempts. Listening to your recordings will help you identify areas for improvement and track your progress over time.

Engaging with complex subjects like the formation of gold not only broadens your knowledge but also serves as an excellent method for developing fluency and pronunciation. By following this guide, you can improve your English skills effectively while enjoying the wonders of science.

Qu'est-ce que la technique du Shadowing ?

Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.

☕ Offrez-nous un café