A week passed with Mitsuki learning to harness the Earth and the Sun's Gravitational Waves. After the week ended, Ai and Prince, Mitsuki's parents returned to her.
"It seems you've gained some level of mastery over the Sun and Earth's Gravitational Waves. As a member of the Kirisawa House Of Dream Knights, there is a bit I need to teach you specifically concerning the dominant affinity of the Kirisawa Family" Ai said to Mitsuki.
"I know a bit about that. The dominant affinity of the Kirisawa House is Flame isn't it Mom?" Mitsuki said.
"Exactly, but not all Kirisawas inherit an affinity for Fire as our dominant affinity. I for instance inherited my Mom, Saito Kusanagi's affinity for Water. This is my dominant affinity but I do possess a passive affinity for Flame" Ai explained.
"You never told me that" Mitsuki admitted.
"You know about my abilities don't you?" Ai asked.
"Yes, your two dominant abilities are your mastery over Water and all its states as well as the ability to utilize the Moon's Gravitational Pull" Mitsuki said.
"Ironically, my passive affinity for Flame as a member of the Kirisawa House manifests in my mastery over the states of Water" Ai admitted.
"How come?" Mitsuki asked.
"You are aware of the significance of Flame and what it symbolizes for the Kirisawa House aren't you?" Ai asked.
"Flame for the Kirisawa House symbolizes Fortitude" Mitsuki replied.
"And amongst the four categories of Flame you know what the trait of the Blue Flame Of Fortitude is don't you Mitsuki?" Ai asked.
Mitsuki nodded.
"Yes, it is also known as the Catalyst Flame because it is the Flame that fuels Transition" Mitsuki replied.
"Do you understand how this category of Flame works?" Ai asked Mitsuki.
"Not really" Mitsuki admitted.
"Let me give you a little lesson as well as a demonstration. Every object with mass converts some of the energy present within it into Heat. Different bodies perform this action at different scales depending first on how large or small the body is and secondly on how conductive the body is but Heat has a unique trait as well" Ai explained.
"A unique trait? What is this unique trait?" Mitsuki asked.
"Heat typically desires to move from regions where it is prevalent or focused to regions where it is less prevalent. In other words Heat typically attempts to move from hotter bodies to colder bodies. When Heat exerts this unique trait, there is always a peculiar side effect" Ai explained.
"A peculiar side effect?" Mitsuki wondered.
"Yes, there is typically an alteration in the mass of the body the Heat either leaves or moves into" Ai explained.
"Can you explain this in detail?" Mitsuki asked.
"We're here at the Lake so let me give you a little demonstration" Ai said as she stretched her hands over the Lake.
Orbs of Water arose from the Lake.
"First of all, I'll direct all the Heat contained in the Liquid Water out of it" Ai said.
As Mitsuki watched, the orbs of Water froze.
"I see" Mitsuki realized what Ai meant.
"This can only work if the surrounding temperature is lower than the temperature of the body. In cases such as this, the Heat contained in the body attempts to escape into the surrounding air which is cooler than the body. It helps to think of the surrounding air as a body as well" Ai explained.
"I see" Mitsuki said.
"Next, I'll do the reverse. I'll move Heat into the orbs of Water" Ai said and did as she had planned.
First, the orbs melted, then they began to vapourize.
"In this case, the surrounding temperature needs to be higher than the temperature of the body to allow the Heat to flow into the body from its environment" Ai explained.
"I understand" Mitsuki observed closely.
"Did you observe anything peculiar as I carried out this experiment?" Ai asked.
"The greater the Heat flowing into the body, the more fluid the body became. On the other hand, the greater the Heat escaping the body the more rigid the body became" Mitsuki noted.
"Excellent observation" Ai praised her.
"This is typically why when two bodies with different temperatures are in contact with each other, the body from which Heat is escaping feels cold while the body absorbing Heat feels hot" Ai concluded the lesson.