Big difference in volume vs. Large difference in volume? which one is better in academic writing?

Question

Big difference in volume vs. Large difference in volume?  which one is better in academic writing?

Answer

Large.

"Big" and "large" are synonyms, but "large" sounds more formal.

Answer

Large.

Actually 'Big' and 'Large' may be used interchangeably. But normally while trying to portray something of significance, we use 'large'.