Half-Moon in Equestria 17

As soon as the sun rose, Twilight was all over you, trying to get you up.
"Come on Twilight, give him a break" Spike says, doing his best to keep her from pouncing you.
"Too late" You groan, sitting up, before you feel Twilight magically carrying you to the table, where breakfast sits. Looking, you see toast and tea on the table. Sighing, you grab a glass, and quickly gulp it down. You immediately feel re-invigorated, and ask Twilight "What kind of tea is this? I've never had one with this much immediate power."
Giggling Twilight responds "Its my own special brew. I use it for late night study sessions, and the mornings after."
"Makes sense" you say, downing another glass, before digging into some toast. While you eat, Twilight is running around, grabbing books and stuffing them into a saddlebag she has across her back.
"Twilight" you say, putting down your current piece of toast "You are'nt going to need any of that. I would advise only bringing a notebook, some writing tools, and chalk if you have any."
Looking dejected, she nods and puts back the books, before getting some quills, an inkwell, and a notepad.
Standing up, you give a quick stretch, before Twilight litterally shoves you out the door.
In the early morning sunlight, you quickly walk towards the field where your circle was set up, Twilight bouncing along behind you like Pinkie Pie. Glancing back, you think 'Speak of the devil'. Pinkie Pie is bouncing along behind Twilight, until Twilight looks back, and Pinkie vanishes.
Pinkie Pie, probably the only living thing that could never learn alchemy.
You chuckle softly at this thought, and Twilight asks "Something funny?".
"Ah, nothing" You reply "besides we are almost there." Gestuing ahead, you cant help but notice Twilight looks a little upset.
Walking towards the middle of the circle, you make sure to step over the lines in the dirt, and Twilight seems to have enough sense to do so as well.nearing the center, you hear the familiar poof of Trixies smoke, and she steps out, announcing to the world "The Great and Powerful Trixie has arrived".
You keep waling, until you reach the center, but you can tell Twilight has stopped, and both she and Trixie were likely staring at eachother in shock. You smile, turn around and sit down.

Twilight and Trixie stare at eachother for a good minute before Trixie hisses out "You! You are the other? Bah, Trixie will deal with you, and then Anon will be Trixies teacher only".
"You! You think you can beat me? I will show you true magic, and send you running back to that little shack of yours with your tail between your legs."
Trixies retort is cut off from a bolt of magic shot from Twilights horn. She quickly raises a shield, and the bolt hits it and is deflected. Trixie counters with some of her own bolts, which are absorbed by Twilights shield.
This continues back and forth for a bit, before you grow bored, and press your palms to the ground, and activate the circle. The mass amount of glowing white lines around them shock Twilight's and Trixie's attentions back to you. the ground slowly rises a bit, the outer eges turning into a channel filled with water about 7 feet acroos, and 4 feet deep. The pile of wood turns into a pair of desks, designed to fit ponys, as well as a chalkboard for you. several tree's sprout up, but these are small, no more than a few feet high. both their faces drop, and you smile, Standing up.
"Now, hopefully you have gotten that out of your system, and we can get to learning." stepping over to the board, you motion the still stunned Trixie and Twilight to their desks.
They both slowly make there way there and sit down, before they both snap at you.
"WHY HER!" they both yell, pointing a hoof at eachother.
"Easy" You say, sitting down "Because I knew of your relation with eachother, and felt it could be excelent fuel for learning. And also, because you poth show great promise in what it takes to be a true alchemist."
"Now" You say, turning to the chalkboard "There is one Law to alchemy. This must be followed in order for alchemy to work. It is  the Law of Equivelant Exchange. It states that in order to gain something, something of equal value must be lost. This may seem like a steep price, but in actuality, it is all in how you manage things. Like this now island for example. the dirt that made up where the trench was turned into water, and was used for raising the height of the island a bit. the pile of wood was turned into the desks and blackboard. the tree's were made of leftover wood and dirt."
"But how? wouldnt all the dirt be needed to be turned into water?" Twilight asks.
"Not quite, the dirt is a solid, and materials come in 3 states. Solid, which is often the most dense, liquid which sits in the middle, and gas which is hardly dense. Turning a solid into a liquid leaves you with more liquid than solid, because the material is less packed together. the same goes for when you convert a liquid to a gas. Of course the opposite is true as well, turning a gas into a liquid leaves much less liquid than gas, and a liquid to a solid works the same way."
Both Trixie and Twilight begin jotting down notes, occasionally giving an evil glare at eachother.
"Next are the Main Taboo's of Alchemy. The largest and most critical one is No Human/Pony Transmutations. This includes trying to bring somepony who died back to life. The reason this is taboo, is because of the dangers and the cost. To put it simply, what could match the value of someones life?"
They both seem to understand the weight of what you say, and nod, before continuing to write notes.
"Chimearagy is the next Taboo. It involves the fusing of animals together to create a new creature. This isnt banned for the same reason asn Human/Pony Trasnmutation is. Its banned because it is Dangerous, and also Unethical, considering you are sacrificing many animals minds to make one new one."
Twilight looks like she is going to vomit, and Trixie is covering her mouth with a hoof.
"Thats simply awful, Why would somepony do that" Trixie asks.
"Many reasons, To make a bestial weapon, better guards, or sometimes just for the heck of it."
Trixie and Twilight look at you aghast.
You simply continue "The last main taboo is transforming materials into money or valuables meant for exchange. This is more in place to keep economys from crashing, and causong imbalances in social structures".
Twilight nods, but Trixie looks unsure at this news.
"Now For the next lesson".