TEKS 5.7B
The student knows that matter has physical
properties.The student is expected to
demonstrate that some mixtures maintain the
physical properties of their ingredients
What are some physical properties of matter?
Color Texture Odor Conducts heat Conducts
electricity
Magnetic Floats or sinks Solubility Boiling point Melting point Mass
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
Salad is an example of a mixture
The lettuce and vegetables do not change when mixed
Is cereal a mixture?
Yes…the properties of the substances do not change.
You can still see the bananas, cereal, and milk.
Is cake a mixture?
No…the properties of the substances change.
The eggs, flour, and sugar change when the cake is mixed and baked.
Substances in a mixture can be separated by their physical
properties…
Milk and cereal can be separated by pouring the mixture through a strainer.
The cereal would be trapped in the strainer and the milk would pass through.
QUESTION:
How could you separate a mixture of sand and sawdust?
ANSWER: You can
separate the sand from the sawdust by adding water. The sand will sink and the sawdust will float.
Sawdust
Water
Sand
QUESTION:
Which scientific tool could you use to separate a mixture of iron filings and sand?
ANSWER: You can
separate the iron filings from the sand by using a magnet.
Iron filings
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
You can make a solution when you stir sugar into water. The sugar dissolves and the water
remains clear.
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
All solutions are mixtures but not all mixtures are
solutions Sugar + Water = ?
Mixture and a solution Sand + Water = ?
Mixture but not a solution
Other examples of solutions:
Soda = Gas + Liquid Jewelry = Solid + Solid Air = Gas + Gas
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.
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.
