passing variables between python 3 scripts using subprocess command ('import * from ...' command just works on module level) [duplicate]

i have a python 3 script('script1') on windows, and i try to pass a variable('var') to another script('script2').

script1:

import subprocess
from tkinter import *
w=Tk()
def script2(var):
    subprocess.Popen('script2.py',stdout=subprocess.PIPE,shell=True)
b1=Button(w,text='var 1',command=lambda:script2('var 1'))
b1.pack()
b2=Button(w,text='var 2',command=lambda:script2('var 2'))
b2.pack()
w.mainloop()

script2:

print(var)

nothing happens...thx all