Hello, how are you?
Good. Photography really is a science as well as an art form. 
That is an fun way to put it. What kind of variables are there in photography? 
I think the focus like in pictorialism is one variable. 
I have always been curious about flash. Is it recommended to use it outdoors?
Using a flash really depends on the time of day the picture is being taken during as well as weather conditions
I am sort of new to photography, can you explain ISO to me?
ISO is the relationship between exposure and the output of image lightness with a digital camera.