#1880. Homogenous and Heterogeneous Mixtures

Science, level: Elementary
Posted Tue Aug 1 17:20:52 PDT 2000 by Lisa (lmcardillo@hotmail.com).
Indiana University of Pennsylvania, Indiana, Pa
Materials Required: plastic cups,plastic spoons salt(11 per group), pepper, water, food dye, kool-aid, glue, sand, soap
Activity Time: 60 minutes
Concepts Taught: TSW learn about homogenous and heterogeneous mixtures. They will also learn how to distinguish them

Procedure
1. Get an empty cup and put two spoonfuls of salt into it. Then add one spoonful of pepper to the salt. Mix the salt and pepper together. What do you notice about the mixture? Is it homogenous or heterogeneous? Record your answers and explanations on the worksheet. Should be able to clearly distinguish between the salt and paper particles.
2. Get another empty cup and fill it a fourth of the way with water. Add 1 spoonful of pepper to the water and mix with a clean spoon. What do you notice? Is it homogenous or heterogeneous? Record your observations and explanations on your worksheet. Should notice that the pepper particles are floating about in the water.
3. Fill another empty cup about a fourth of the way with water. Add about three or four drops of food dye to the water and mix it. What type of mixture is it? Record your observations and explanations on you worksheet. The water turns the color of the food dye after mixing.
4. Get another empty cup and fill it about half full with water. Add 1/2 package of Kool-Aid to the water. Is this mixture homogenous or heterogeneous? The water will turn the color of the Kool-Aid.
5. Now fill a glass halfway with water and add about two spoonfuls of sand to the water. What do you notice? The sand will just sink to the bottom of the cup once the mixing is over. What type of mixture is this?
6. With another empty cup fill halfway with water and add two spoonfuls of soap. Mix the two together so that bobbles form. What type of mixture is this? The soap will causes bubbles to form on top of the water and throughout the water.
7. Now put one spoonful of glue into an empty cup and mix three drops of food dye with it. What type of mixture is this? The glue will turn the color of the food dye.
Explanation of Observations
The first, second, fifth, and sixth mixtures are heterogeneous. This can be proven by looking at the mixtures that were created. In these mixtures, we can see two different phases. A heterogeneous mixture is the physical combination of two substances with two distinct phases. As I said these mixtures had two different phases.
The third, fourth, and seventh mixtures are homogenous. We can see this by looking and observing the created mixtures. They each look the same throughout and had uniform properties. This matches the definition of homogenous mixtures.