Make facts, time and time again, the heart of science (8)
I believe the answer is:
generate
'make' is the definition.
(I know that make is a more specific form of the action develop)
'facts time and time again the heart of science' is the wordplay.
'facts' becomes 'gen'.
'time' becomes 't' (abbreviation).
'and' says to put letters next to each other.
'time again' becomes 'era' (era is a kind of time. I am not sure about the 'again' bit.).
'the heart of' means to look at the middle letters.
The central letter of 'science' is 'e'.
't' after 'era' is 'erat'.
'gen'+'erat'+'e'='GENERATE'
Can you help me to learn more?
(Other definitions for generate that I've seen before include "Engender" , "Cause to arise; produce" , "Give rise to" , "Create for teenager" , "Bring into existence for teenager" .)