The little dragon is naturally able to complete the hourglass, while looking at this is a small thing, but in terms of the measurement of time, in terms of timely function, there is no high-precision clock, and the error of the hourglass timer is about 30 minutes, and the error is between plus or minus one for thirty minutes. Pen × fun × Pavilion www. ｂｉｑｕｇｅ。 ｉｎｆｏ

The advantage is that it will not be affected by external factors. Like in Yao Ran's cognition, in ancient times, there were incense burners and water drops. However, it is slightly different from the hourglass timer in terms of accuracy and calculation. The root cause of this is that it is easy to be influenced by the outside world.

However, in comparison, the hourglass will not be affected by any other influence when there is no external interference, such as shaking and shaking, so the hourglass is more suitable for measuring fixed time when there is no clock.

The time of the hourglass is directly related to the curvature of the inner wall of the hourglass, as well as the amount of sand stored in the hourglass, and of course, the material of the sand itself.

When Xiaolong came in, he saw a table of cups and bottles, and two round eggs stacked together, and he didn't know what they were for, and his face was full of question marks. Yao Ran is anxious about this technology product last night today. Of course, there was no time to explain things to Xiaolong.

And good students and top students are naturally curious babies, so Xiaolong is naturally curious about the glassware on the table. Then, of course, Yao Ran was now busy going to the car at the door to dig for sand, so Xiaolong naturally went to his teacher to ask.

And Yao Huo was also studying the cup he got at the moment. Xiaolong jumped to Yao Huo's side by himself, and the two of them began to mumble about what these things were for, but in fact, Yao Huo didn't know what those two balls were for.

Yao Ran took the sand back into the room and put it in the grinding mash, and began to grind it repeatedly with the grinding stone. The ground sand was filtered by Yao Ran with water on a piece of cotton cloth, and after tossing for more than half an hour, the sand had to be dried in the shade.

And the two masters and apprentices in front of the table are still studying what the two balls are for. Yao Ran looked at it and smiled for a long time, these two people are also very good talents in terms of machinery, but they can't understand a simple small hourglass.

After drying the sand powder, Yao Ran put the sand into the hourglass. Finally, I chose the bottom of the cup I just used, and after roasting it on the fire for a while, I sealed the last hole with the finished hourglass filled with sand.

Yao Huo saw that Yao Ran had finished loading the sand, and he somewhat understood what Yao Ran was going to do, but he just hadn't figured it out yet.

Xiaolong, looking at Yao Huo's posture of enlightenment, he was also in a hurry. But I really don't have a clue at all. But after waiting for a long time, Xiaolong didn't wait for his teacher to say anything? It's just on the side, ah, ah.

In the end, Yao Ran finished sealing and waited for the sealing to cool down, but until it cooled down, Yao Huo didn't say what this thing was for.

In the end, Yao Ran said, "This is an hourglass." "At this time, I saw that the temperature of the glass in the retinal system had dropped to normal temperature. Yao Ran picked up the hourglass that was flat on the table, and there was one end of the sand in it, facing up, and the side without sand was below, because there was nothing to fix the hourglass, he could only hold the hourglass with his hand, and the sand in the hourglass began to flow from the glass egg above to the glass egg below.

Yao Huo's eyes were straight, why could it be like this. You can also see the sand flowing inside, and the transparency of the blown glass is much higher.

Therefore, you can also see the flow direction and flow of the sand inside more intuitively. And Yao Ran motioned for Yao Huo to hold the hourglass by himself. Yao Ran went out by himself, found some wood, and made a bottom and a few pillars.

When I came back, the sand in the hourglass had just run clean, which should have been exactly half an hour. Because of the metering function of the retinal system and the comparison of the entire hourglass, the error of each reversal of the sand flow for half an hour will not exceed 20 seconds.

In the current state, with such a large amount of sand and time, there is basically no big error in this half-hour hourglass.

And the base Yao Ran directly made 3 at once, because there were two other ones on the table, Yao Ran found the cup that was a little slanted just now. And the old man also kept watching Yao Ran's movements.

When Yao Ran handed the half-hour hourglass into his hands. The old man looked surprised, and Yao Ran said, "This half-hour hourglass is left for you to make a standard unit of measurement, and the hourglass made will be compared twice according to this time, and you can pass it without error." After passing the mile, use such a wooden frame to pack, then wrap it with hay, pack it in a wooden box, and then fill it with hay, and let people transport it to Yaozhai to sell it, and your future income will come out of these hourglasses. Do you understand? ”

"Including the expenses and expenses you recruit students, but the money given to students can't be too small, otherwise no one will work for you, you know? Yao Ran is good to your students, so that they can better study more things. ”

Yao Ran didn't know what the old man's personality was, but through nearly a day of contact, Yao Ran felt that this old man was not bad, but the wheels of the car would turn, and people would also change. Even if you pretend to be it, you can pretend for a long time, right?

So Yao Ran said the next words, and then Yao Ran saw that the old man had already picked out another box of materials in his hand and all of them had been ground. After seeing it, Yao Ran was stunned for a moment, and he didn't say that he was going to make glass. At this time, Yao Ran noticed that he was playing with the child with Hou Yun in the back, and when he felt Yao Ran's gaze, Hou Yun also looked over.

Then he pouted, looking at Yao Ran as if you didn't do it for me, Yao Ran also understood, the old man only picked up the materials because of Hou Yun's face, and grinded to help Hou Yun make another one.

And after the last one, the crooked one was originally intended for Hou Yun, and no one wants to use the things that the old man is making now, and the popular utensils now are that the common people love to use ironware, and the high-level ones are made of porcelain with a higher price.

Yao Ran smiled in his mouth, sat back on the stool in front of the stove, took the materials in the old man's hand, poured them into the crucible, and then took the scissors and baked them on the top of the flame again.