It is important to know who the audience is, because when presenting something for someone, you will want to know what they enjoy, and if they will be bored, or not. It's important, so that they actually are interested and pay attention.
Closest thing I could find or think of would be Thermocline. A point in which the warmer surface water mixes with the cooler deeper water
What happened show us your question so we can awnswer it