Your neighbor has gone on vacation for a week and has asked you to take care of her aquarium. The aquarium is filled with water and contains a few fishes and plants. Unfortunately, your neighbor forgot to tell you whether the water is fresh water or salt water and you need to know before adding any more water. You cannot analyze the water by smell and you certainly do not want to taste the water!
Devise a method of determining which type of water is in the aquarium using only materials available in the kitchen
You could take a sample of water to your local pool store where they can analyze the salt content. Because of the rise in popularity of salt water pools, they would more than likely have a test.