By Mary Lou Alfieri and Susan M. Frack
The word salt conjures up different images to different people. To the chemist salt is known as sodium chloride. To the geologist salt is known as halite. To most people salt is just plain salt. However, plain old salt comes in a variety of forms. There's table salt, rock salt, canning salt, animal salt, and softener salt. One question remains...are all these forms of salt the same.
To discover the properties of salt in its different forms.
- different types of salt (table, rock, canning, animal, and softener salt)
- filter paper
- glass slides
- pertri dish (1/2 for each type of salt)
- eye dropper
- Place a small sample of each type of salt on a separate piece of filter paper. Examine each type of salt with the magnifiers. Record your observations for each salt type in the data table.
- Measure out 10 grams of each type of salt. (Use the salt that you obtained in step one add to it if needed). Compare the sizes of the "piles" of each type of salt. Record your observations.
- Try to determine the hardness of each type of salt. Use the penny, nail, glass, etc. to do this. Record your information.
- Label each petri dish for a specific salt type. Place 10 drops of water in each dish. Add salt until no more will dissolve. (**It will not take very much salt). Compare the residues left in each dish. Record your observations.
- Discuss the data you've collected with your group members. Develop a statement that explains why all the different salts are all salt.
- What types(s) of crystals did you observe?
- Was there a difference in the hardness of each type of salt?
- Was there a difference in size of the "piles" of 10 grams of each salt?
- Write your statement about salt here: