Look, They Like each Other!
Background: An important way of understanding the world around us is to classify the things in it. This lab will help you learn about materials called "mixtures." There are three types of mixtures: solutions, alloys and mechanical mixtures. During this lab you will make solutions and mechanical mixtures and then examine some of their properties.
Materials:
| tap water | sugar |
| wooden splints | iron filings |
| three 100 ml beakers | pepper |
| salt | a magnet |
Making Solutions
Process:
1. Use a grease pencil to write your group number on the side of a 100 ml beaker. Now, fill a test tube 3/4 full of water and add a scoop of salt about size of your little fingernail to the water. Stir the solution with the wooden splint until all the salt disappears. Place the test tube in your numbered beaker.
2. Reread the first step and make a sugar solution in another test tube. Place this test tube in your numbered beaker.
3. Now, using the same steps, see what happens when you mix pepper and water in another test tube. Place the test tube in your beaker.
Questions:
1. What happened to the salt and sugar particles when they came in contact with water?
2. Look closely. Can you see the components of either solution?
3. Were you able to make a pepper solution? Explain your results.
4. So, do all materials form solutions?
5. a) How might you separate the sugar solution into its components?
b) How about the salt solution?
6. How might you separate the water and pepper?
Making Mechanical Mixtures
Process:
4. Tear two loose leaf pages into halves. On one half, mix together two small piles of salt and sugar. Set the page to one side.
5. On a half page, mix together two small piles of salt and pepper. Set the page to one side.
6. On a half page, mix together two small piles of salt and iron filings. Set the page to one side.
Questions:
7. Look closely. Do the particles of mixtures disappear when they come in contact with each other? (Recall what happened to the sugar and salt when they were combined with water.)
8. How might you separate the sugar and salt?
9. How about the salt and pepper?
10. How could you separate the salt and iron filings?
11. Can the components of mixtures and solutions be separated by direct, physical means?