Mixtures

 

Objective

To learn the definition and characteristics of a mixture.  Also, to learn that a solution is a type of mixture.

 

TEKS: 5.7(B) demonstrate that some mixtures maintain the physical      properties of their ingredients

 

Supplies

          plastic plates or pie tins

          trail mix (pretzels, peanuts, m&ms, raisins)

          popsicle sticks

          sand

          iron filings

          tweezers

          magnets

          napkins

          plastic cups

          sugar

 

Focus

          Today we will learn about mixtures.

          Tell them mixtures are all around us.  Ask what they think a mixture is.  Ask for examples, which may include air, sand, cracker jacks, sea water, etc.

         

Explanation/Model/Guided Practice

          Mixture- the combination of two or more different substances (write on board where everyone can see it)

          Activity:

1.     Have students observe the physical properties of each ingredient for the trail mix and tell you what to record on the chart (on transparency).

2.     Next, have them mix the ingredients on the plate/tin with the popsicle stick and observe the physical properties of the mixture.  Record their observations of the mixture.

3.     Ask them if they can separate the mixture back into its original parts.  Add this to the definition on the board.  

4.     Have the physical properties of the ingredients changed?  Ask them if they can make a conclusion about mixtures from this information.  Add this to the definition of a mixture.

 

Independent Practice

          Activity:

          Have students repeat the above activity with iron filings and sand and the worksheet.

1.     Observe the properties of the iron filings and sand.  Record on the chart.

2.     Mix the two substances with the popsicle stick.  Record your observations of the mixture.

3.     Hypothesize the ways your group can separate the mixture using the tools provided. (Magnets not available at this point.)  If students do not think of using a magnet in a minute or two, ask them what they know about iron.  Now what do they think they should use?  When a student suggests a magnet, be sure to ask them to keep it in the baggie so it will be easy to collect the iron filings.

4.     When the mixture is separated, have students note whether or not the physical properties of the two substances were altered.

5.     Have students complete the included questions.

 

If there is enough time--------

          Let students mix some sugar and water.  Talk about how a solution is a type of mixture in which the particles of the substances are evenly distributed.  IMPORTANT- Be sure to tell them that solutions can be solid (brass & other alloys), liquid (sugar water, orange juice), or gas (air)- see chart on C29