Home
Вход
Регистрация
Loading...
Практика аудирования
Практика аудирования
/
Video
/
TED-Ed
/
What’s happening inside a dishwasher? - Rachel Yang
What’s happening inside a dishwasher? - Rachel Yang
Выберите режим обучения:
Посмотреть субтитры
Выбрать слово
Переписать слово
Highlight:
3000 Oxford Words
4000 IELTS Words
5000 Oxford Words
3000 Common Words
1000 TOEIC Words
5000 TOEFL Words
Субтитры (80)
0:06
In 1883, American socialite Josephine Cochrane
0:10
was suddenly widowed and left with mounting debts.
0:13
But she had an idea she hoped would turn her fortunes around.
0:18
Years of hosting lavish dinner parties
0:20
and watching her dishware get chipped during handwashing
0:23
convinced her the world needed a better way to clean dishes.
0:27
So, she poured the little money she had left into building a prototype,
0:31
eventually showcasing her dishwashing contraption at the Chicago World's Fair.
0:37
This was the first step towards the modern dishwasher,
0:39
whose basic design remains remarkably similar to Cochrane's.
0:44
When you press start on a dishwasher,
0:46
it fills a small basin with water that's heated up to 60°C.
0:51
Then the pre-wash cycle begins.
0:53
A circulation pump sends high-pressure water up into spray arms,
0:57
where it shoots out of angled nozzles, propelling the arms to spin.
1:02
The water recollects in the basin, where, in most modern models,
1:05
a turbidity sensor measures the water’s dirtiness
1:08
by seeing how much light passes through it.
1:11
The dishwasher then adjusts the wash time and water temperature accordingly
1:15
and transitions to the wash cycle.
1:18
Detergent is released and the dishwasher cycles the now-detergent-filled water.
1:23
This dirty water drains and clean water, heated to an even hotter 68°C,
1:28
is circulated for a final sanitizing rinse.
1:32
This is at least 10 degrees warmer than a typical sink’s hottest water,
1:37
and hot enough to eliminate most foodborne bacteria.
1:40
Finally, the dishwasher may enter an optional drying cycle.
1:45
While that's how most dishwashers work,
1:47
how well they actually clean depends on several factors—
1:51
the first being the type of detergent you use.
1:54
Detergent comes in three forms: liquid, powder, and pods.
1:59
The main ingredient in all three is the surfactant.
2:02
These special dual-ended molecules remove food residues by latching onto them
2:07
with one end and pulling towards the water with the other.
2:11
You'll also find surfactants in regular dish soap, but detergents go further.
2:16
They often contain enzymes that break down food into smaller pieces
2:20
that surfactants can easily tug away,
2:22
and bleach, which disinfects and removes stains.
2:27
So, which detergent form is best?
2:29
Liquid detergent can only contain bleach or enzymes,
2:33
since bleach breaks down enzymes in liquid form.
2:36
Powder detergents solve this problem by coating powdered enzymes
2:40
with a protective wax,
2:42
allowing them to work alongside powdered bleach.
2:45
But even more effective are dishwasher pods that separate components
2:49
using a plastic film.
2:51
Though, pods may have environmental impacts—
2:54
some studies claim the plastic biodegrades in a couple of months,
2:58
while others find it persists for much longer.
3:02
How you treat your dishwasher, and the dishes you put in,
3:05
can also affect performance.
3:07
A dirty dishwasher or filter can trick the turbidity sensor
3:10
into thinking dishes are dirtier than they are,
3:13
prompting an unnecessarily long wash cycle.
3:16
And while it might seem counterintuitive,
3:18
rinsing dishes beforehand can also cause problems.
3:22
If dishes are well rinsed,
3:23
the turbidity sensor will detect minimal grime and trigger a short wash cycle,
3:28
which may not be enough to break down any stubborn stuck-on crust.
3:33
Further, the enzymes in detergent are designed to latch onto food residue,
3:37
so the best practice is to simply scrape your dishes before loading.
3:42
What’s more, by letting the dishwasher do all the work,
3:45
you'll also save water.
3:47
Dishwashers recycle water during the wash cycle,
3:50
so they only use 3 to 5 gallons.
3:53
That’s equivalent to running a kitchen sink for up to 2.5 minutes.
3:57
So if you think handwashing your dishes might take longer than that,
4:00
it might be worth just running a load.
4:04
Of course, there are reasons to not throw in the towel
4:06
on handwashing altogether.
4:08
Since dishwashers use very hot water,
4:11
they can warp wooden items and certain plastics,
4:14
damaging seals in travel mugs or storage containers.
4:18
Sharp knives can also be dulled by detergents,
4:20
or they can even damage the dishwasher itself.
4:24
And there's also an energy consideration.
4:26
On average, a standard dishwasher cycle uses about the same amount of energy
4:31
as leaving your TV on for 12 hours.
4:34
Clearly, there are situations when handwashing makes more sense.
4:38
But if you’re faced with a dinner party’s worth of dishes,
4:41
a dishwasher can be a welcome reprieve.
What’s happening inside a dishwasher? - Rachel Yang - Video học tiếng Anh
