in if statement. why can' t we compare two string and return a print statement?

Question

if '10'>'5':
print ('hello')

Answer 1

Python doesn't see that as numbers you could also try
if "house" > "car" :
print("hello")

how should the Programm know the size of an object?

But you could compare them exactly.

if "5" == "5":

that will work.

Answer 2

You can. However string comparison is not what you think in python. The greater and less than signs will compare the order of the string rather than its actual size. Because 1 is before 5, any string starting with it will be less than any string starting with 5.
Think of it as a comparison of words in a dictionary. The position of "alpha" will always be before "beta" in a dictionary, therefore its position is always less than "beta".