You can use a pH indicator to measure some liquids to see whether they are acids or bases. Just like in determining if a solution is an acid or a base, Jesus told us of an indicator to determine if we are his disciples, it is the love God gives us for one another....
When we go through things that we think have no purpose and are not helping us to succeed at our plans, we need to remember that in God all things work together for good. Your trials, while they are difficult for you at the time, are working to the furtherance of His Kingdom. Not yours....