In this lesson you will:
Resources:
Use the definitions in any textbook or read them and see examples on this page.
Check out these internet sites:
http://www.psinvention.com/mixtures.htm
http://afhs2.sd381.k12.id.us/whitaker/physcispecmix.htm
http://home.earthlink.net/~dmocarski/chapters/chapter8/main.htm
http://solospirit.wustl.edu/education/Science%20Side/exp5.htm
| Salt and water | Copper sulfate and water |
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| chalk and water | Soil and water |
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| Oil and vinegar | Oil and water | kerosene and water |
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| Liquid laundry starch and water |
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A common example of the tyndall effect occurs when you can see the path of the movie projector light in the movie theater.
For more information on the tyndall effect, do an internet search for tyndall effect or visit some of the suggested sites before you do your lesson activity.
In a mixture of salt and water, the salt is the solute and the water is the solvent.
In a mixture of alcohol and water, the alcohol is the solute and the water is the solvent.
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Lesson 12: Types of Mixtures |
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A mixture consists of two or more pure substances. Various terms are used when describing mixtures Homogeneous: used to describe substances that look the same throughout. Homogeneous substances have one phase and uniform composition. Heterogeneous: used to describe substances in which you can see more than one color or type of matter. Heterogeneous substances have more than one phase and a nonuniform composition. Phase: is a visibly distinct portion of matter Tyndall effect: is seen when a mixture makes a beam of light visible. There are several types of mixtures. They are:
Solutions: are mixtures made by mixing a solute and a solvent. The solute is the substance that dissolves. The solvent is the substance that does the dissolving. Solutions are homogeneous and do not show the tyndall effect. (Help with solute and solvent) Suspensions: are heterogeneous mixtures of a solid and a liquid in which the solid does not dissolve. Suspensions will settle when left standing undisturbed. Suspensions will show the tyndall effect. Emulsions: are a special type of suspension. This mixture consists of two liquids that do not mix. Since the liquids do not mix, emulsions are heterogeneous. Emulsions will settle into layers when they are left standing undisturbed. Emulsions will show the tyndall effect. Colloidal Dispersions: are mixtures with characteristics part way between a solution and a suspension. Colloidal dispersions may appear homogeneous but are actually heterogeneous. Colloidal dispersions do not settle when left standing undisturbed for a period of time. Colloidal dispersions do show the tyndall effect.
Visit one, none or all of these sites to gain a better understanding of the different types of mixtures and the tyndall effect. site a: Scroll down to find the different types of mixtures at this earthlink site site b: Read about the Tyndall Effect site c: SilverGen site showing the tyndall effect with lasers Part 1: Check out the Poseidon Software and Invention site. As you read, look for the link to Oobleck. If you didn't look at the recipe for OOBLECK, then go back to the site above and note the recipe for OOBLECK. Make the OOBLECK and note its properties. Remember that OOBLECK is an example of a colloid. Part 2: Mix up an example of a solution, suspension, emulsion and colloidal dispersion. Test whether each of these mixtures shows the tyndall effect by shining a flashlight at the side of the container. If the mixture makes the beam of light visible then the mixture shows the tyndall effect. Part 3: NOW, try some questions to determine whether you recognize the various types of mixtures. Click the white dot below that indicates the correct answer. If you get most of the answers correct then it shows that you have a good understanding of the terms discussed above. 1.
Salt and water is an example of a:
2.
A mixture of clay and water is an example
of a:
3.
A mixture of alcohol and water is an example
of a:
4.
A mixture made of oil and water is an
example of a:
5.
A mixture is described as a heterogeneous
liquid where two liquids are visible and
the mixture shows the tyndall effect.
This mixture would be a:
6.
A mixture is described as looking homogeneous,
not settling when left standing undisturbed
and does show the tyndall effect. This
mixture would be classified as a:
7.
A mixture is described as being homogeneous
but does not show the tyndall effect.
This mixture would correctly be classified
as a:
8.
Which of these is an example of a colloidal
dispersion?
9.
If you wanted to make an emulsion, which
of the following substances would you
add to water?
10.
If you want to make a solution, which
would you mix with water?
Classify each of the following mixtures as a solution, suspension, emulsion or colloidal dispersion. Click outside the white box when you are finished typing your answer to each question. This will let the computer know that it should check whether your answer was correct or not. 1.
A glass of whole milk
2. A glass of pop
3.
A cup of black coffee
4.
Italian salad dressing
5.
Gravel and water
6.
Hot chicken Lipton noodle soup
7.
A glass of cool iced tea
8.
Ketchup
9.
A glass of orange juice
10.
A mixture of water and diesel fuel
You will assess yourself as to whether you understand the terms described in this lesson. You will be tested on these terms in your unit test. If you feel that you don't understand these terms well enough, then read the lesson material again. Be sure that you read all the examples and look at the pictures that pop up when your mouse rolls over the highlighted words. Try to find all of these highlighted words that cause something else to pop up. Then redo the activity and the assignment. Read each pop up message as it is displayed on the screen. |
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