What do we call a pure sample that's run next to the tested substance to see if it's a component in the mixture?

def func1(x):

   return (x-32)*(5/9)

def func2(x):

   return (x/2.237)

def main():

   x = ""

   while x != "x":

       choice = input("Enter 1 to convert Fahrenheit temperature to Celsius\n"

                      "Enter 2 to convert speed from miles per hour to meters per second: ")

       if choice == "1":

           temp = input("please enter temperature in farenheit: ")

           print(func1(float(temp))," degrees celcius.")

       elif choice == "2":

           speed = input("please enter speed in miles per hour: ")

           print(func2(float(speed))," meters per second")

       else:

           print("error... enter value again...")

       x = input("enter x to exit, y to continue")

if __name__ == "__main__":

    main()

Explanation:

two function are defines func1 for converting temperature from ferenheit to celcius and func2 to convert speed from miles per hour to meters per second.