Evaporation and Salt

An experiment to find the percentage of three separated components
Research Question:
Is it possible to separate salt, sand and iron filings from each other in a mixture, to figure out the percentage of each component in the original mixture?
Background Research:
In this Investigation, I will be separating sand, salt, iron fillings in a mixture and finding their percentages. Iron is a magnetic solid which is incapable of being dissolved in water. Salt is a non-magnetic solid which is capable of being dissolved in water. Sand is a non-magnetic solid which is incapable of being dissolved in water. I used this research to help me complete my experiment. (Separating salt, sand and iron)
Hypothesis:
If the sand, salt, and iron mixture can be broken down in its separate ingredients, then the percentages of the sand, salt, and iron from the larger mixture will correspond with those percentages from our smaller sample of sand, salt, and iron.
Variables:
Independent Variable | Separating salt, sand and iron fillings | Dependent Variable | The percentage of each component in the mixture | Controlled Variable | What would happen if you didn’t control this Variable? | How are you going to control this Variable? | The amount of water | If I didn’t control this then I could have had too much water to evaporate and it could take long. | I will control this variable by making sure there is a right amount of water. | The flame of the Bunsen burner | The flame will change the temperature of the water being evaporated. If I didn’t the control it might not boil or it could get to hot. | Turn it up so the water evaporate slowly and fast making sure I get the salt | | |