def add_drip_columns(cave_results_df):
    """
    Calculates Drips per min
    Calculates Drip Rate Error
    Adds all as columns ad returns input df.

    Parameters
    ----------
    cave_results_df : pandas dataframe

    Returns
    -------
    cave_results_df : pandas dataframe
    """
    # Data Conversions
    cave_results_df['DripsPerMin'] = 60.0/cave_results_df['DripInterval']

    # Error Propagation
    cave_results_df['DripRate_Err'] = (60*cave_results_df['DripInterval_err'] / 
                   cave_results_df['DripInterval'].pow(2))
    
    return cave_results_df