| Chizpurfle
Join Date: Mar 2006 Location: underwater
Posts: 10,319
 x9
|  Stuck inside with Sirius | *Splish-Splash* | bamBAM | ☁ Spooktacular ☁
Wow, they were quiet today. Noble hadn’t intended for them to work in silence…nor for them to stay in their seats as Bernadette and Carsyn seemed determined to do. It was meant to be a fun lesson; something a little different…and even those camped out at the back (Claudine) seemed to be taking it more seriously than nodded. He almost nodded appreciatively as Morgan broke the silence, and, gave not only a correct answer, but also the correct reasoning. Hopefully some of the others were taking note. Naya and Catherine certainly seemed to have written plenty down on their parchments so far. Meanwhile, Isla had the sense to actually get up and look more closely at the objects, and Cole and some of the others soon followed.
As quills were downed, and eyes returned to the front, Noble took it as a sign to move on. [b] “As I’m sure you’ve realised, there wasn’t necessarily a one-to-one match for metals and objects. However, this is how I would have matched them…” He picked up his piece of chalk and moved to the blackboard, writing the name of the object matched to each metals as he explained his reasoning. “Gold, as I’m sure most of you are aware, is used for jewellery. It’s valuable, and is pretty inert – that is, doesn’t react with chemicals on your skin and leave the black marks Bernadette mentioned earlier. Copper, is cheap, durable and readily available. This makes it good for coins. Its value, or lack thereof is also important here – you don’t want the metal the coin is made from to be worth more than the coin’s face value.”
“As Morgan shared, mercury is the liquid metal used in thermometers. As it gets warmer, mercury expands in a predictable way, which we can use to tell the temperature.” Hmm, what next? “Lead is a soft metal. Easily pliable by hand, one common use is to piece together the often elaborate shapes in stain glass. What lead would not be good for is fencing – iron would be a much better choice, due to it’s strength. However, in pure form it is prone to oxidisation – more commonly known as rusting – which can make it fragile, and therefore, a metal mixture, or alloy as Noah said earlier, would prove a better choice.”
And that left two metals. “Iron can also be used for broom footplates. However, on several of the more advanced models, they’re more likely to be made of aluminium. Strong and light – of which, the latter is obviously hugely important when considering resistance and weight in the air. And finally, magnesium can be used for sparklers, as it burns easily with a bright white flame.” Noble paused briefly, letting those who were still writing catch up. As he did so, he moved back to his desk.
“I’ve mentioned several properties of different metals now…and maybe you considered others whilst trying to match up the metals and objects. As well as helping us choose the right metal for the job, certain properties can also help us identify the metal in a substance. I said that magnesium is good for sparklers because it burns a bright white. Well, different metals produce different colour flames…and this is very useful indeed, if, say, you’re designing magical fireworks.”
Yes, magical fireworks. They had heard that correctly.
Noble leant forward, carefully adjusting the air hole of the lit burner on his desk until the flame turned blue. He then put on his safety goggles. “The experiment we’ll be doing in the rest of the lesson is called the flame test, and we can use it to identify the metals from their flame colours. In each of these containers,” he gestured to the opaque jars on his desk, “is a powdered compound containing a different metal. First you’re going to dip one of these pre-soaked spills into the powder. They’re pre-soaked in water so that wood doesn’t burn, only the metal.” He picked up a spill, and dipped it in the powder a couple of times, so that the bottom inch or so was decently covered. “Then you’re going to hold it in the middle of the blue flame, and observe the colour change as the powder reacts.” He did so, the flame turning a bright purple; that particular compound contained potassium. “Once you’re done observing, put the spill safely on the heatproof mat to cool. Do that for each powder, and use the table of colours on page 243 in your textbook to identify the metal.”
He put the spill on his mat, before picking up the rag he used for cleaning the blackboard. He wiped off the previous list of metals and objects, and proceeded to write up the instructions for the experiment for them to refer to if needed. As he did so, he was reminded of something. “You’ll need to carefully light your burners from the one on my desk. Dry spills are next to the sink as usual. Once you’ve put on your goggles, you may begin.”
Quote:
Originally Posted by Instructions Equipment:
Safety goggles
Burner
Heat proof mat
Spills - dry for lighting the burner, damp for the metal tests
Variety of metal salts, labelled A-E.
Instructions:
1) Light your gas burners from the flame at the front of the class using a dry spill.
2) Dip a clean damp damp spill into the metal compound, and make sure it’s well covered.
3) Hold the powder-covered spill in the middle of a blue flame, and watch the colour it burns.
4) Once you're done observing, put the burnt spill on the heatproof mat. Quote:
Originally Posted by colours they burn A - blue-white
B - purple
C - white
D - red
E - green Quote:
Originally Posted by textbook Copper - green
Iron - brick red
Magnesium - white
Potassium - purple
Lead - blue-white
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