A simple home experiment:
Find two points, such a hill/mountain-tops that are visible from each
other, but 10 or 20 miles, at least apart east/west..
This is not sufficient to prove the earth is spherical. This method was used to
calculate the diameter of the earth, already knowing that it was a sphere and the sun was
very far away. To prove it was not flat, one has to use 3 locations. Using just two only
helps to prove the stupid flat earther's thought that the sun was much closer to the
flat earth. 3 locations prove that it can't be flat because the angle changes too much
over distance. It can be done in any direction but is easier to do North to South because
time of day only needs to be at high noon and distance known.
One need only watch a ship approaching shore from any direction to
notice that the horizon is curved.