the cool thing about science is that everything is modelled. equations are found for everything. and then people use it to find other things. problem is the conditions are always ideal. like no interactions with each other. infinite time. stuff like that. so then the smart scientists model up a new correction factor. so make their ideal model into another ideal model that has less idealness. but it is still ideal for some parts, and that must be changed. so in the end. there is nothing that is constant. everything is variable. that sucks.