Notes

Mixture : when substances are mixted without any reaction (no rearrangement in chemical bonds)

Compound : same as mixture but with a reaction (change of chemical bonds)

Physic states : solid (atoms and molecules packed together and moving slowly), liquid (less dense and more dynamic movement) and gas (least dense and very active movement)

Phase transition : a change of physic state, a change in the amount of energy as created by heat (or magic).

• Solid to Liquid: Melting
• Solid to Gas: Sublimation
• Liquid to Solid: Freezing
• Liquid to Gas: Evaporation or Boiling
• Gas to Solid: Deposition
• Gas to Liquid: Condensation

Solution : a mixture with an element in small quantities (the solute) is dissolved in an element in bigger quantities (the solvant). Can be solid, liquid or a gas.

To brew a potion : ingredients alone are not enough. Needs energy (heat / magic) and the right order to add ingredients.

Essay

Prompt
I will give you a few options for your essay this week. The only stipulation is that it needs to be 200 words or more. You can write on ONE of the following topics:

a. What is a phase transition? Name and give an example of 3 different phase transitions we see in Magical or Muggle life and discuss what causes the transition.

OR

b. Describe what mixtures, compounds, and solutions are. Provide an example of at least one of them that you have used in your Magical or Non-Magical life (and identify which of the three it is).

Response (topic a)
In the universe, matter can be found under three states : as a solid, a liquid or a gas. The difference between these states is the density of the atoms and molecule, and how much they move. Solids have the highest density, and their particules move very slowly. Gases have the lowest density and their particules are in very activement movement.

A phase transition is when matter changes its state ; for example, when a solid becomes a liquid. This phase transition is called "melting". We see it commonly : by instance, when you held an ice cube in your hand, it starts to melt and transform into water. 

Every phase transition is triggered by energy : it can be heat or magic. In the ice cube case, it's the heat of your hand that causes the ice to change into water.

Another common phase transition is "boiling" : when a liquid transforms into a gas. It can be seen everytime you cook and boil water : water in gas form is created above the pan. The cooking fire heat is what create the transition.

A rarer transition is when a solid becomes a gas : it's called "sublimation". When a solid transforms into a gas, it usually goes through a liquid state : if you put ice cubes in a pan and heat them, they will melt before they boil. For the transition to be direct, you have to supply more energy.