15 - Are You Like Sugar, Sand, Oil, or Egg? (Mixtures: Solution, Suspension, Emulsion, Colloid)
Author(s):
Ingrid Sherwood
School(s):
Aldine I.S.D.
Subject:
Science
Grade level:
4
Time Frame:
2 hour(s)
Description:
The student will learn about different types of mixtures and use the knowledge to write a social commentary.
Educational Objectives:
Vocabulary:
Vocabulary:
mixture
solution
suspension
emulsion
colloid
Aldine Benchmarks:
7, 8
Materials:
Optional:
1. example of a mixture, such as a salad or a collection of various pattern blocks
2. example of a solution, such as salt water or sugar water
3. example of a suspension, such as sand in water
4. example of an emulsion, such as oil and water
5. example of a colloid, such as mayonnaise or homogenized milk
Teacher Background:
A mixture is a combination of substances. All solutions, suspensions, emulsions, and colloids are types of mixtures.
A solution is a liquid that contains a dissolved substance -- a solid, liquid, or gas. The solvent is the liquid in which the substance is dissolved. The solute is the substance dissolved in the liquid. Solutions do not have to be liquid. There are solid solutions, such as glass, and gaseous solutions, such as air.
An emulsion is a suspension of small globules of one liquid in another. Water is a polar substance. Water is miscible with other polar liquids which dissolve in water. Oil is a nonpolar substance. Oil is miscible with other nonpolar liquids which dissolve in oil, but not all oils dissolve in each other. Oil and water do not mix; they are immiscible; they make an emulsion.
A suspension is a mixture of a solid in a liquid where the solid does not dissolve in the liquid but stays temporarily suspended in the liquid until gravity pulls it down.
A colloid is a solution containing tiny undissolved particles that permanently remain suspended in the liquid, such as homogenized milk and mayonnaise.
Advanced Preparation:
Procedures:
1. Show or tell students about different types of mixtures:
mixture - combination of substances, such as a salad or combination of pattern blocks
solution - a liquid homogeneously mixed with a solid, such as salt water or sugar water. Sugar or salt dissolves in water. The particles of sugar or salt actually separate and move between the particles of water. The salt or sugar can be retrieved by distilling the water or allowing the water to evaporate.
suspension - a mixture of a solid in a liquid where the solid does not dissolve in the liquid but stays temporarily suspended in the liquid until gravity pulls it down, such as sand shaken in a jar of water. Another example of a suspension is a snow globe.
emulsion - two liquids that do not mix, such as oil and water.
colloid - a solution containing tiny undissolved particles that permanently remain suspended in the liquid, such as homogenized milk or mayonnaise. Oil and vinegar do not mix, yet they are ingredients in mayonnaise. An egg added to the oil and vinegar acts as an emulsifying agent to prevent the oil droplets from coming together.
2. Have students ponder the way the substances in the different mixtures behave by translating the behavior of the substances in the mixtures to the way people behave in social situations.
3. Give some examples of translating the behavior of the substances in mixtures to the behavior of people in social situations. For example:
One day I felt like a wedged tomato in a salad. I was tossed around (by salad tongs), got caught in a downpour (of salad dressing), lost half of my seeds, and came right out of my skin. Another day I felt like a cherry tomato in a salad. I rolled when I got tossed around, let the rain (salad dressing) slide right off, and stayed intact, no matter how hard the onions and cucumbers attacked me.
4. Have students tell you if you're acting like sugar in a solution, sand in a suspension, oil in an emulsion, or egg in a colloid in the following scenarios:
1-My clothes/hair were so dorky, that I vanished into the crowd. (like sugar dissolving in water)
2-There was just no way I could stay away from my friends. We had too much to talk about. My friends and I just couldn't stay mingled with the others; we always floated together. (like oil in vinegar)
3-My best friend just called, and I had so much energy that I felt like I was flying. Eventually gravity pulled me down to Earth. (like sand shaken in water)
4-It was my party, and everyone was going to get along. (like an egg emulsifying oil and vinegar in mayonnaise)
5. Have students choose a situation in which they felt or behaved like sugar, sand, oil, or egg.
6. Have students write a paragraph describing their behavior in relation to others. The paragraph can be written as an expository or a riddle; students can tell what they were and describe the situation or describe the situation and have others guess what they were. They must give clues to enunciate some knowledge of mixtures.
Formative assessment:
The student will write a social commentary to enunciate some knowledge of mixtures.
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