Shadowing Practice: What Is A Semiconductor? - Learn English Speaking with Video

Science!

Here I have a circuit with a battery, light bulb, and gap.

If I fill this gap with a metal, the light comes on.

If I fill this gap with glass, the light stays on.

You probably already know this because metal is an electric conductor and glass is an insulator.

But what happens when I fill this gap with a silicon wafer? wafer.

The light stays off so you might think the silicon is an insulator but what if I heat it up?

Thank you.

It lights up.

The silicon is insulating at room temperature but conducts electricity when it's very hot.

It's a semiconductor, whose conductivity changes based on the environment.

This special ability makes semiconductors the perfect brains for electronic devices.

Circuits of small semiconductor switches,

called transistors, are at the heart of computer chips and enable them to do math and run programs.

Semiconductors have enabled electronics to become smaller, faster, and more reliable.

But what is it exactly about these semiconductors that allow them to either conduct or insulate?

In a single atom, electrons can occupy specific energy levels.

When multiple atoms bond, the electrons are shared between them.

But because the atoms are now interacting,

the energy levels shift around.

In a solid, trillions and trillions of atoms interact with each other.

Their individual energy levels smear into energy bands.

For a material to conduct,

the electrons must be able to jump from lower energy states to higher ones.

The spacing of these energy levels and how they're filled with electrons determines if if the material is a conductor,

insulator, or semiconductor.

If there's a huge gap between the lower energy levels and the higher ones,

it's hard for electrons to jump to the higher ones,

so current can't flow, and it's an insulator like this glass.

Metals have no gap at all.

Electrons can move to the higher energy levels with no problem.

Current can flow.

Semiconductors fall somewhere in the middle.

They have a medium-sized band gap.

So technically, I can make this glass conduct electricity

if I added enough energy through heat to push the electrons into a higher band.

But that amount of heat would either melt or break the glass before it actually conducts.

This is true of most insulators.

The amount of energy needed to make them conduct is just too high.

But in a semiconductor, the band gap is small enough

that electrons can jump into the higher energy band so that current can flow.

The amount of heat we apply determines how many electrons jump into the higher band and how much current flows.

And heat isn't the only way to change the conductivity in a semiconductor.

We can also use light,

electric currents, and in a computer, electric fields.

As I've said, computers are made up of semiconductor switches called transistors that switch between conducting and insulating.

Computers use electric fields because heat is slow and would burn too much energy.

We can turn this wafer into a computer chip by printing a circuit of transistors on it using a process called photolithography.

Here, in the photo room,

we cover the wafer with a light-sensitive material and expose it to light that we shine through a pattern mask.

Then, we develop the wafer,

like film and photography, which leaves behind a pattern that becomes the circuit.

Printing the transistors at once lets you make circuits that are smaller and cheaper than if you built them from individual parts.

Transistors make up the logic elements,

the memory components, and the communication modules that let computers talk to each other.

With semiconductors, you can cheaply add transistors to almost any device you can think of,

from spaceships to servers to maybe even your toaster.

Semiconductors have enabled the technological revolution,

the internet, the computer, and the cell phone.

No semiconductors, no information age.

I'm Jamie and thanks for watching this episode of Science Out Loud.

Be sure to check out some of our other videos,

including mine, on how computers compute.

Check out our website for more information.

The end is...

I'm just like...

✨ Aanbevolen Video

20 zinnen

Woordenschat en spreektips bij deze les

Deze spreekles op niveau C2 is gebaseerd op de video “What Is A Semiconductor?”. Deze woorden komen het vaakst terug: semiconductor, energy, electrons, gap, computer. Deze video bevat 66 zinnen en 690 woorden om na te spreken. Het gesproken deel duurt 4:43. De spreker praat in een gelijkmatig tempo van ongeveer 146 woorden per minuut, prettig om te shadowen. Slechts 78% van de woorden hoort bij de 3.000 meest gebruikte Engelse woorden, dus de woordenschat is pittig.

Belangrijke woorden in deze video

De 15 moeilijkste woorden uit de video, met uitspraak en betekenis:

Woord	Uitspraak	Betekenis
semiconductor zelfstandig naamwoord	/ˌsɛmikənˈdʌktə/	halfgeleider
transistor zelfstandig naamwoord	/tɹænˈzɪs.tɚ/	transistor
insulator zelfstandig naamwoord	/ˈɪn.s(j)ə.leɪ.tə(ɹ)/	isolator, isolatiemateriaal
wafer zelfstandig naamwoord	/ˈweɪ̯fɚ/	wafel
atom zelfstandig naamwoord	/ˈætəm/	atoom
insulate werkwoord	/ˈɪnsʊleɪt/	isoleren
silicon zelfstandig naamwoord	/ˈsɪləˌkɑn/	silicium
conductivity zelfstandig naamwoord		geleiding
conductor zelfstandig naamwoord	/kənˈdʌktɚ/	dirigent
interact werkwoord	/ɪn.təˈɹækt/	interageren, elkaar beïnvloeden
compute werkwoord	/kəmˈpjuːt/	uitrekenen, berekenen
spaceship zelfstandig naamwoord		ruimteschip, ruimtetuig
toaster zelfstandig naamwoord	/ˈtəʊ̯s.təː/	broodrooster
bulb zelfstandig naamwoord	/ˈbʌlb/	bloembol
module zelfstandig naamwoord	/ˈmɑd͡ʒul/	module

Phrasal verbs die je zult horen

Woord	Betekenis
check out werkwoord	onderzoeken
leave behind werkwoord	achterlaten

Grammatica in deze video

De structuren die de spreker het meest gebruikt, met de exacte woorden uit de video:

Structuur	In de video
Present perfect have/has + voltooid deelwoord — iets uit het verleden dat nu nog telt	have enabled · I've said
Lijdende vorm be + voltooid deelwoord — het gaat om wat er gebeurt, niet om wie het doet	are shared · are made

Uitspraak om op te letten

De spreker gebruikt 6 samentrekkingen en verkorte vormen, zoals I'm, can't, I've. Spreek ze kort uit, zoals je ze hoort.

Lange woorden — let op de klemtoon: semiconductor /ˌsɛmikənˈdʌktə/, insulator /ˈɪn.s(j)ə.leɪ.tə(ɹ)/, technological /ˌtɛk.nəˈlɑ.dʒɪ.kəl/

Klanken die Nederlandstaligen lastig vinden:

Stemhebbende eindmedeklinker — /b/, /d/, /g/, /z/, /v/ niet verscherpen: bind /ˈbaɪ̯nd/, bulb /ˈbʌlb/, expose /ɪkˈspoʊz/
/æ/ — opener dan de Nederlandse “e”: transistor /tɹænˈzɪs.tɚ/, atom /ˈætəm/, interact /ɪn.təˈɹækt/

Zo oefen je met deze video

Luister de hele video één keer zonder te spreken en noteer de woorden die je niet kent.
Spreek zin voor zin na op normale snelheid en herhaal elke zin tot je ritme gelijk is aan dat van de spreker.
Neem jezelf op en vergelijk met het origineel; let daarbij op woorden als semiconductor, transistor, insulator.

Wat is de Shadowing-techniek?

Shadowing is een wetenschappelijk onderbouwde taalleermethode die oorspronkelijk is ontwikkeld voor professionele tolkentraining en gepopulariseerd door polyglot Dr. Alexander Arguelles. De methode is eenvoudig maar krachtig: je luistert naar native Engelse audio en herhaalt het onmiddellijk hardop — als een schaduw die de spreker volgt met slechts 1–2 seconden vertraging. In tegenstelling tot passief luisteren of grammaticadrills, dwingt shadowing je hersenen en mondspieren om echte spraakpatronen tegelijkertijd te verwerken en te reproduceren. Onderzoek toont aan dat het de uitspraaknauwkeurigheid, intonatie, ritme, verbonden spraak, luisterbegrip en spreekvaardigheid aanzienlijk verbetert — waardoor het een van de meest effectieve methoden is voor IELTS Speaking-voorbereiding en echte Engelse communicatie.

Shadowing-techniek: lees de volledige stap-voor-stap-gids →

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