Oil, plastic, rocks.
Substances that all living things
soft water
Water, salt, dissolved gases, rocks, sea shells, and sometimes oil/trash.
The things dissolved or floating around in the water.
Oxygen is dissolved in water. Some things such as water movement and air currents/ wind aid in the mixing process. Also, aquatic plants release oxygen into the water.
Maybe the water has some CO2 dissolved in it.
Ruth would know that some of the copper sulphate crystals had dissolved in the water by observing if the water changed color to blue, which indicates that the copper sulphate dissolved. Additionally, she could check if there are fewer crystals at the bottom of the container, as they would have dissolved into the water. Ruth can also test by inserting a clean spoon and checking if any more crystals can stick to it, indicating that some have dissolved.
If you are looking for examples, here are some: salt water sugar water sodium hydroxide dissolved in water Kool-Aid coffee tea
The oxygen dissolved in water is a measure of dissolved oxygen (DO).
This is called: a solution
Water soluble things are all the things that get dissolved in water completely and homogeneously. A few common examples are salt, sugar, alum, copper sulphate and powdered milk.
Some limestones are made by precipitation of dissolved calcium carbonate. Some cherts are formed from dissolved silicates in thermal springs and evaporite minerals, such as gypsum and rock salt (halite) are formed by evaporation of water from solutions of dissolved minerals.