A Chinese podcast · Same story, 4 levels
麻省理工做出了一块可以吞下去的电池：它在猪的身体里工作了三天，然后自己化掉了
MIT Built a Battery You Can Swallow. It Powered a Device Inside a Pig for Three Days, Then Dissolved.
About this story
Swallowing a battery is one of the things every child is warned about. On 21 September 2026 a team led by Giovanni Traverso at MIT published a paper battery designed to be swallowed: magnesium and molybdenum trioxide on paper, wrapped in a cellulose film inspired by the edible rice paper around a sweet. It delivers about 1.84 V — more than a household AA — occupies a quarter of a capsule, and powered both a signal tag and a gastric stimulator inside pigs for three days before dissolving. One caution from outside the study: degrading is not the same as disappearing. Chinese listening practice at four levels. HSK 3 Chinese listening practice.
This is an HSK 3-4 Chinese listening episode that runs about 5 minutes. The full Mandarin script is shown with tap-for-pinyin and a line-by-line English translation, so you can listen and read at once — comprehensible input in the sense of Stephen Krashen's i+1 theory. It teaches 12 key vocabulary words such as 办法、安全、材料 and walks through 3 grammar patterns, each explained in English with examples. The same news story is retold at 4 difficulty levels — use the level selector above to find the version that is challenging but still understandable for you.
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原文Read the complete story in Chinese. Reveal pinyin and English only when you need them.
English transcript reference
Let's start with something almost everyone was told as a child.
Do not swallow batteries.
If a small child swallows a battery, the adults have to get them to hospital immediately.
Because what is inside a battery will burn the oesophagus and the stomach.
Which makes the next sentence sound very wrong indeed.
On the twenty-first of September this year, a team produced a battery you can swallow.
And they have already had pigs swallow it.
Why would anyone set out to make such a thing?
To answer that, we have to start from a different problem.
Doctors want to see what your body looks like on the inside.
The old approach was to send you to hospital and image you from the outside with a big machine.
But there is a limit to what you can see from outside.
So people came up with another route: stop looking through the body and send the instrument in instead.
That thing already exists, and it is shaped like a pill.
You swallow it, it photographs as it travels, and in the end it comes out by itself.
This whole category is known as ingestible electronic devices.
And they are all stuck on the same problem: electricity.
Anything that needs power needs a battery.
But what is inside a battery must not touch the body.
The current approach is to seal the battery up tightly so it never touches you at any point of the journey.
Most of the time, this is safe.
But the approach rests on one condition: that outer layer must not break.
That outer layer can break, and the whole device can get stuck in the gut and fail to come out.
If either of those two things happens, the risk you were avoiding becomes a real accident.
So there is only one direction for a genuinely clean solution.
Make the battery out of materials that were never going to harm anyone.
Better still, have it dissolve safely inside the body once its work is done.
The answer from the MIT team is a battery made of paper.
What is inside it is magnesium.
Magnesium is something the human body needs anyway, and that matters a great deal.
The battery is wrapped in a paper skin that holds off the acid in the stomach.
The idea came from sweets.
The researchers say what they had in mind was the edible rice paper on the outside of a sweet.
That paper dissolves slowly, and that is precisely what they wanted.
Two numbers are worth remembering.
The first is size.
The battery takes up only a quarter of an ordinary capsule.
The remaining three quarters can hold a machine, or medicine.
The second is power.
Inside the body it delivers one point eight four volts, a little more than a household AA.
They tested it in two stages.
The first stage used little power.
They sealed the battery into a capsule with a small tag that sends a signal, and had a pig swallow it.
People outside the pig really did receive the signal, which proved the power was getting through.
The second stage used a lot of power.
They used the battery to drive a device that delivers electricity inside the pig's stomach.
In hospitals, that kind of electrical stimulation is used to help the stomach empty.
During the test the pig's hunger hormone level rose, showing the device really was working.
Last comes the timing.
The battery supplied power inside the pig for roughly three days.
After three days the stomach acid got through that outer paper skin, and the battery began to corrode and dissolve.
This is not a malfunction; it is exactly the result they were after.
But one academic who was not part of the research raised a very sharp question.
He said: dissolved is not the same as gone.
We still need to know what it dissolves into, how much the body absorbs, and whether it damages the gut.
Especially when a patient has to swallow one again and again.
There is no answer to that yet, so using this in people is still a way off.
Worth adding: making a battery edible is only one of the routes.
There is another route running the opposite way: use food as the battery directly.
A team in Milan has built a dissolvable battery out of riboflavin, capers and nori seaweed.
It cannot yet power anything useful, but it is already edible.
Both routes are heading for the same place.
Turning a machine that has entered your body from something that must be carefully sealed off into something your body can simply deal with.
Now put yourself in it.
A doctor hands you a capsule and says there is a battery inside that will dissolve in your body after three days.
Do you swallow it?
Listen again
Try it without the transcript and notice what sounds clearer.
What vocabulary does this episode teach?
词汇HSK 3. 真正干净的办法只有一个方向 — 想办法 is the collocation; you think one up, never make one.
HSK 3. 大部分时候这样是安全的 — safety stated as a frequency, which is the whole weakness.
HSK 3. 让电池本身就用不会伤人的材料做 — the one-sentence statement of the solution.
HSK 3. 这正是他们要的结果 — said of the battery corroding, which is the counter-intuitive part.
HSK 2. 这一点很重要 — flagged for magnesium specifically, because that fact carries the safety case.
HSK 2. 它们都卡在同一个问题上 — one shared bottleneck across a whole category of devices.
一块可以吞下去的电池 — note 块, the measure word used for a flat slab like this one.
只占一颗普通胶囊四分之一的地方 — the size is what makes it useful rather than merely clever.
胃酸穿过了外面那层纸皮 — the clock that ends the battery's life, by design.
The wrapper on a soft milk sweet. The researchers say this is literally where the idea came from.
带动一个装置，在猪的胃里放电 — the high-power half of the test.
猪体内的饥饿激素升高了 — the measurable proof the stimulator was working.
* beyond level超纲词
What grammar patterns appear in this episode?
语法只要……有一件发生，就……
If any single one of these occurs, the consequence follows. Used to show that a system depending on nothing going wrong is not actually safe.
只要这两件事里有一件发生，本来躲开的风险就变成了真的事故。
这不是……，这正是……
Refusing one reading and supplying another. Reserved here for the moment the battery falls apart, which sounds like failure and is the design goal.
这不是坏了，这正是他们要的结果。
……，不等于……
X does not amount to Y. The sharpest sentence in the episode is built on it, and it is the standard Chinese frame for puncturing a premature conclusion.
他说，化掉了，不等于没有了。
Proper nouns
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