How can you distinguish between the amounts of water from other material in a container?

Question

I have a cactus in a glass container at the corner of my room. The cactus is dead so I do not put water in that container any more. Recently someone has started put water in that container. NOW the total container weighs 2.4 kilograms. How can I find out NOW how much water is in there without emptying it or by spending more than 5 minutes with it? I will buy any equipment to do this, as long as it does not cost too much.

An easier way to simulate this picture in your mind would be – ‘you have a container full of sand/ soil, a nice plant (you do not want to kill it or remove it) and water. By using some kind of electronics equipment how can you find out the weight of sand/soil and the weight of water in that container? (Above constraints apply)’

Please feel free to ask any relevant question. Thank you!!

Answer 1

Weigh it, let it all evaporate and then weigh it again, you dont have to spend any more than 5 minutes "with" it but it will take more than 5 minutes