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  • Were at one of the UK’s leading firework manufacturers

  • and this is their 125 mm air starburst shell.

  • A 20-minute display will not drop 10,000 fireworks.

  • And 60% of them will release bad boys.

  • Each one costs around £ 30 and contains half a kilo of explosive.

  • And we have to launch it to a height to over 100 meters.

  • As you can see, it’s much more than a bowl of loose powder.

  • And this is how they test the component parts.

  • The basic firework recipe is flash powder,

  • a potent form of gunpowder.

  • It’s a mixture of Potassium Perchlorate and Aluminium.

  • These ingredients are mixed together in 7 kilo batches

  • and a small sample is ignited to make sure it has a requisite brightness.

  • This sample has been mixed with Strontium to make it glow red and it’s clearly a pass.

  • Well, this sample has Barium added to glow green.

  • Again, it does the trick nicely.

  • If a firework is packed with this loose powder,

  • it would explode in one instant flash.

  • So the gun powder mixture is turned into pellet to prolong the burn time.

  • As the burning pellets go to the sky,

  • they create the spreading patterns we are all familiar with.

  • This test checks whether this particular pellets size will burn of its efficient time

  • to create a burst diameter of 18 meters.

  • There are two roughly formed rings of starscentral ring and an outer ring.

  • The outer ring is made of stars of a slightly larger size.

  • Therefore their behaviour and when they burst in the middle

  • ignites these stars and blows them in the circle formation.

  • The initial will be the heavy larger stars will travel further.

  • That’s in the sky youll see one small ring and then a larger ring around it.

  • The next test checks the fireworks 2 fuses.

  • Firstly, a length of fuse is measured down to which itll slowly burn inside the firework

  • to ensure it ignites at the correct altitude.

  • A fuse this length should burn any about 12 seconds.

  • It has, so it’s a pass.

  • As second external fuse is needed to lose the firework.

  • Racking the fuse in paper should contain the hot gases

  • and make the fuse burn much quicker.

  • We expect this link to fuse to burn within a hundred fifty second.

  • Looks like a pass to me.

  • The final test is to ensure the firework is no louder than European regulation of 120 decibels.

  • The same noise level as enigmatic drill at close range.

Were at one of the UK’s leading firework manufacturers

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B2 中上級

I Didn't Know That - 花火 (I Didn't Know That - Fireworks)

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    Go Tutor に公開 2021 年 01 月 14 日
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