1. TEKS 5.5C The student knows that matter has physical properties.
The student is expected to
demonstrate that some mixtures maintain the physical properties of their ingredients

2. What are some physical properties of matter?
Color
Texture
Odor
Conducts heat
Conducts electricity
Magnetic
Floats or sinks
Solubility
Boiling point
Melting point
Mass

3. Mixtures Form when two or more substances combine
Keep their physical properties
Can be separated by their physical properties
Do not form a new substance

4. Salad is an example of a mixture
The lettuce and vegetables do not change when mixed

5. Is cereal a mixture?
Yes…the properties of the substances do not change.
You can still see the bananas, cereal, and milk.

6. Is cake a mixture? No…the properties of the substances change.
The eggs, flour, and sugar change when the cake is mixed and baked.

7. Substances in a mixture can be separated by their physical properties…
Milk and cereal can be separated by pouring the mixture through a strainer.

8. The cereal would be trapped in the strainer and the milk would pass through.

9. QUESTION:
How could you separate a mixture of sand and sawdust?

10. ANSWER:
You can separate the sand from the sawdust by adding water. The sand will sink and the sawdust will float.
Sawdust
Water
Sand

11. QUESTION:
Which scientific tool could you use to separate a mixture of iron filings and sand?

12. ANSWER:
You can separate the iron filings from the sand by using a magnet.
Iron filings

13. Solutions are a special kind of mixture
One of the substances
dissolves in another
The substance spreads out evenly
Solutions may be clear or colored

14. You can make a solution when you stir sugar into water
You can make a solution when you stir sugar into water. The sugar dissolves and the water remains clear.

15. Do all substances dissolve?
No…if you mix sand with water, the sand does not dissolve but settles on the bottom of the glass.
Sand + water

16. All solutions are mixtures but not all mixtures are solutions
Sugar + Water = ?
Mixture and a solution
Sand + Water = ?
Mixture but not a solution

17. Other examples of solutions:
Soda = Gas + Liquid
Jewelry = Solid + Solid
Air = Gas + Gas

18. Solutions can be separated
Most solutions can be separated by evaporation.
To separate a saltwater solution, let the water evaporate.
Once the water is gone, the salt will be left.

19. Challenge
You are given a mixture of salt, sand, and gravel. Design a plan to separate this mixture? What tools would you use? List your steps in order.
NOTE: Answers may vary. Sample answer: Add water to the mixture. Pour mixture through a wire mesh screen (small enough to trap the pebbles but large enough to let the sand flow through). This will separate the pebbles from the sand and the salt. Using a funnel with filter paper, pour the sand and salt mixture through to trap the sand in the filter paper allowing the salt water to flow through. Put salt water solution in a petri dish and allow the water to evaporate leaving salt crystals.