Читать книгу The Double Dangerous Book for Boys - Conn Iggulden - Страница 24

INTERESTING CHEMICAL REACTIONS

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Chemical reactions can be extremely dangerous. Read these for interest, but either don’t try them or get an adult involved and accept that trying them comes with risk. You should wear goggles, masks and gloves when using potentially toxic chemicals.

One difficulty of writing the first Dangerous Book was getting hold of chemicals. Even for something simple like growing crystals, finding a reliable source for copper sulphate or potassium permanganate was almost impossible. Since then, the website eBay will supply all sorts of interesting chemicals – for a price.

As a test, we bought pieces of sodium and potassium. These metals react so violently with water that they have to be kept under oil – just the moisture in air will cause them to combust. You may have seen them used in school chemistry labs: tiny pieces dropped into a bowl of water to fizz around and glow purple or orange. In comparison, dropping a large piece into a drinks bottle half-full of water will cause it to explode after two or three seconds. Do not try that. If you do try that, make sure you run a long way and are safely behind something; learning about the properties of sodium and potassium is interesting, but it should not be at the expense of eyes or fingers. Please be clear about this: the man who invented the stunt kite became a recluse when he heard a boy had been carried off a cliff by one of his kites – a death that would not have happened if not for his invention. If in doubt, don’t do it.

Without resorting to the internet, some things found around the home can also be made to react in interesting ways. Of course, sometimes a reaction is just setting something on fire.

1

FLAMING BUBBLES

This first one should not be tried without adult supervision. It involves large bursts of flame and, frankly, of the eight or ten times we tried it for this chapter, we almost set the house on fire twice and actually did burn all the hair off our fingers and forearms. It was spectacular, but come to think of it, just do not try this inside. Or at all.

We used a kitchen bowl half-filled with water, some liquid soap, a box of matches and some butane gas of the sort that refills cigarette lighters. It’s available from any supermarket.

Upturn the butane gas in the water and press the nozzle against the bottom of the bowl. The gas will form large bubbles in the soap – exactly like a bubble bath, but, you know, filled with highly flammable gas.

Wet your hand in cold water. Do not forget to do this. Move away from the bowl. On the two occasions we nearly set fire to the kitchen, it was when we forgot to move clear of the bowl and the butane-filled spatters of foam on the kitchen counter.

Touch a match to the bubbles. The flame burns bright and large, but if you remembered to wet your hand, you won’t be burned before the flame is out. Probably.

2

MATCH AND MATCH, OR MATCH AND CANDLE

This is fiddly, but nice when it works. When you blow out a candle or a match, a line of smoke rises in a curling grey/white line. That line can be set on fire, so that the flame travels back down and relights the candle or match below.

This could easily take half a dozen attempts. We suggest you never try this on a date, or at a formal dinner table. Not because of fumes or setting something on fire. It just might suggest you are not completely focused on the event.

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3

THE FIRE SNAKE

This next one is pretty spectacular, though the main ingredients can be found in most kitchens. Now, it can be done indoors, in theory. It smells quite pleasant, like burned sugar or toasted marshmallows. It does involve flame and considerable heat, however, so there is always a chance you will burn the house down. Outdoors on a windless day might be a better idea. You may have seen versions of it in indoor fireworks sets. We’ll call it the Ram’s Horn, or possibly the Dragon’s Tail. Or the Fire Snake.

You’ll need some ordinary sand, lighter fluid and a kitchen cereal bowl. The bowl will get hot, so stand it on something solid, like a piece of tile. We used an old wooden chopping board.

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Fill the bowl almost to the brim with the sand and pack it down. Scoop out the centre, or mould the sand so the centre is lower than the edges. Take 10g (⅓oz) of bicarbonate of soda (ordinary baking soda) and mix it with 40g (1⅓oz) of ordinary white sugar. Use a cup or any container for the mixture.

Squirt lighter fluid onto the sand until it is dark and wet with it. Be generous – it’s not easy or advisable to add more later. When you have drenched the sand in the bowl, pour in the mixture of baking soda and sugar – doing your best to keep it to the centre of the bowl. The ideal is a cone shape. Narrower cones will create longer snakes – or horns. Or dragon’s tails.

With a match, touch a flame to the lighter fluid. There is no going back from this point. What happens will take up to half an hour. The heat will ignite the mixture. A snake (or possibly a ram’s horn) of thick black ash rises slowly out of the bowl and begins to curl on itself. The ash is actually cool to the touch, but the bowl is not, so be careful not to get burned poking at it.

You’ll be able to get different widths of snake (or tail) with different cone diameters of the baking powder/sugar mix, but keep the same ratio of 1:4 as it works well.

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After half an hour, the bubbling comes to an end. By then, the ash should be about eighteen inches to two feet long (45–60cm). It is a thing of awe.

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The ash is formed from carbon dioxide released when the baking soda is heated – the burning sugar caramelises and creates the ash, while the baking powder inflates it. When the flames have gone out, you can usually lift the entire snake (or dragon’s tail) away from the bowl. Take it outside if you are overcome with the desire to squish it, however.