an observation
In physics, when you notice something happening, you are making an observation. Observations are the first step in the scientific method and are used to gather information about the natural world. These observations can lead to hypotheses and further investigations.
A "prohibition notice" is a piece of paper that formally prohibits something from happening, often issued by a regulatory authority or governing body to enforce compliance with laws or regulations.
5 sences
Probability?
To not let something happen. "He prevented the ball from getting in the goal."
Something is happening Something is happening
Give him/her something to notice
The chance of something happening.
Verbs show that something is happening or exists. They express actions, states, or occurrences in a sentence.
No nothing is happening
The chance of something happening can be called a probability.
I think you find out when you notice that strange things are happening to you, but for Percy Jackson, he was first attacked by the fury and then was told by his mom, so I would think that he would notice something's up when a flying beast attacks you asking for Zeus' lightning bolt.