How to Physically Separate a Mixture of Table Salt & Sand

You already know that salt dissolves but sand doesn't just from visiting the beach.

A lot of things in nature don't come neatly separated into their component parts the way we might like them to be. Separating the components of a mixture is an important problem in chemistry -- when chemists are trying to make a drug, for example, they may need to separate one mirror-image form of the drug compound from another. In beginning science courses, however, you'll probably be given much simpler assignments, like separating sand from salt. If you ever find yourself stuck with this assignment, here's how it works.

Things You'll Need

• Water
• Beaker
• Spoon
• Erlenmeyer flask
• Funnel
• Filter paper
• Safety glasses
• Tripod
• Wire gauze mesh
• Bunsen burner
• Lighter or match

Instructions

1. Pour the sand-salt mixture into a beaker. Add water -- preferably the volume of water will be double that of the sand and salt -- and stir for two minutes.

2. Place a funnel in the mouth of an Erlenmeyer flask and fit filter paper inside the funnel by folding the paper filter in quarters and opening up the center of the folds to make a cone.

3. Pour the sand-and-water mixture into the filter-paper cone. The filter paper will capture the sand but not the salt, which is dissolved in the water.

4. Put on safety glasses, place a tripod over a Bunsen burner and seat wire gauze mesh on top of the tripod. Place the beaker on the wire gauze. Carefully light the burner.

5. Heat the solution to boiling. Once the water has evaporated, only your salt will be left, and you will have successfully separated sand from salt.

References

• The Nuffield Foundation and Royal Society of Chemistry: Separating Sand and Salt