If you travel back to the Song Dynasty, how can you generate electricity?

Browsing our phones may be a very important reason for us to live in this world. If we suddenly travel back to ancient times, such as the Song Dynasty, how can we ensure that our phones have power? After all, even if we bring a power bank, it can only last for a few days. Therefore, we must consider a perfect way to keep our phones fully charged!

Which method of power generation is our preferred choice?

If your power bank has a solar cell, you probably don’t have to bother with it. You can just expose it to the sun when you have nothing to do, but not everyone is so lucky, so you still have to find a way to generate electricity! So in the Song Dynasty, more than 1,000 years ago, what conditions could satisfy us to make a generator?

To make the most primitive generator that can generate electricity, we know the principle that when a wire moves in a magnetic field, it can generate electricity. However, the voltage and current of a single wire are too low, so a coil made of many wires must be used. So what accessories are needed to make a mechanical generator?

Rotating power source

Magnets that generate magnetic fields

One or more coil windings

A rotating power source is probably the easiest to find. A waterwheel that rotates under hydraulic drive is one power source, or you can make a windmill that rotates under wind power. I believe that most people can make one, but it requires some knowledge of woodworking. But we are modern people, even if we have not done it, we have at least seen it. It may not be particularly difficult to make a rotating windmill!

Magnets have existed since the Song Dynasty, so it is not difficult to obtain magnets. However, it is estimated that the quality of natural magnets at that time was not very good. For example, the magnetic field was not strong enough, or not uniform enough. But it is better than having nothing, so just make do with it!

The most troublesome part is the coil winding. After all, there was no concept of electrical wires at that time. However, this does not seem difficult. The gold wire production technology had already been mature at that time. This wire drawing method is also applicable to copper wire. The key is the copper smelting process, because the red copper wire has good toughness. Then it is wrapped with yarn and coated with varnish to become yarn-covered wire!

Yarn covered thread

With these things, you can make a generator. The shaft can be made of cypress or rosewood, and the bearings can be replaced by sliding "oil-containing" bearings! But there is a problem, and it takes a lot of experiments, because the charger can accept 220V or 110V AC power, and the frequency requirement is not that high, so there is no voltmeter. If you know how to calculate, you have to increase or decrease the number of turns of the coil so that it can output enough voltage.

By the way, the coil is placed in the middle and the magnets are on both sides, so the electricity generated is alternating current. If you want direct current, you have to make a rectifier ring, which is really troublesome!

Are there any simpler batteries? Making a generator like this is too complicated, almost equivalent to mobilizing the woodworking, smelting, textile and other industries of the time. You must travel through time and space to a wealthy family, otherwise there is no financial support for you to do this thing! So are there other simpler ways to generate electricity?

Voltaic cell

Also called the Voltaic pile, this battery is the simplest. It was invented by Italian physicist Count Alexander Volta in 1800. This battery is made up of many stacked units. Each unit is made of a zinc plate and a copper plate, with absorbent cotton cloth soaked in salt water in the middle. If the Song Dynasty could not find zinc plates, iron sheets could be used instead.

The structure of the zinc (can be replaced by iron sheets) copper voltaic pile

Each stacked unit can get an open circuit voltage of about 0.76V, and 6 units can be close to the USB output 5V. Of course, the open circuit voltage and the load voltage are two different things. If you require a battery with an output of 5V and dozens of milliamps, you should stack them several times in number and then connect hundreds of them in series to get the required voltage!

Prototype of the voltaic pile

But there is a problem. If the open circuit voltage is too high, it is easy to break down the electrical equipment. However, there is a way to stack the loads in series, so that the electrical equipment will not be broken down. However, the charging cable must be modified. Take out the two power cords in the USB cable and connect them to the positive and negative poles respectively! Note that the copper sheet of the voltaic battery is the positive pole, and the iron sheet or zinc plate is the negative pole.

Schematic

Of course, it is not that simple. The battery will be consumed very quickly and needs to be constantly replenished with salt water or replaced. It is estimated that hundreds of kilograms of salt may be consumed to charge a mobile phone, and it may not be fully charged! Or you can replace the salt water with dilute sulfuric acid, but in the Song Dynasty, it is not so easy to find dilute sulfuric acid!

But there is a problem: if there is no signal, why charge the phone? If you are a lover of science e-books, then you can bring the knowledge in these books to ancient times and accept the influence of modern science more than a thousand years ago. If so, the foundation of modern science or modern medicine has been laid 1,000 years ago, and you will create a great civilization!

Of course, it doesn't matter if you don't have one. An astronomy app can allow Shen Kuo of the Song Dynasty to directly revise the calendar, and various theories of celestial motion will sprout in the Song Dynasty about 500 years earlier! Or you can also build a telescope, which is a great helper in both war and astronomy.

Even if there was nothing, a calculator would have greatly benefited the mathematician Qin Jiushao at that time, and a precise clock could have been used to set up too many scientific experiments. A camera could have discovered the curve of the sun's movement in the sky. There were also so many pop music, and I wonder how much more music scores would have been added at that time. If there were dance videos or football videos, the sport of Cuju might have continued to this day... In fact, there is no if, you are all thinking too much!