system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What do the upside down triangles in math and physics mean?

For example, Maxwell's equations contain upside down triangles. What exactly do they represent? 

How does it apply to the real world?
gpt
It represents a vector derivative. 

It tells you how a vector (a quantity that has both an amount and a direction) will change over time.

For instance, in some of Maxwell's equations, it represents how a charged particle's movement is affected by electromagnetic fields over time.