CLASSIFYING MIXTURES

Amber Sager

PURPOSE

To classify mixtures as solutions or colloids using the Tyndall effect

MATERIALS

sodium hydrogen carbonate

cornstarch

stirring rod

distilled water (or tap water)

flashlight

masking tape

3 jars with parallel sides

teaspoon

cup

PROCEDURE

In a cup, make a paste by mixing 1/2 teaspoon cornstarch with 4 teaspoons water.

PROCEDURE

Fill one jar with water. Add one half teaspoon sodium hydrogen carbonate to a second jar and fill with water. Stir to mix. Add the cornstarch paste to the third jar and fill with water. Stir to mix.

PROCEDURE

Turn out the lights in the room. Shine the beam of light from the flashlight at each of the jars and record your observations

Water Corn StarchBaking Soda

CONCLUSION

Some of the sources of error for this lab would be that I forgot to use the distilled water so I ended up using that tap water. That might have effected my results because tap water has certain minerals that distilled water doesn’t have. I can improve next time by following the directions completely.

CONCLUSION

The jars that I could see the light through were the water and water mixed with baking soda. I believe what made the light visible was that the mixtures had particles that were too tiny. If it was filtered I don’t think you would be able to see through it because the water is what makes it able to see through. If you were to replace the baking soda with sugar or salt I think it would be the same result because your salt and sugar are small.

CONCLUSION

If you were to replace the corn starch with flour or diluted milk it would again cause the same thing because of the consistency of the three items. You can distinguish a colloid from a suspension because you can’t see through a colloid but you can see through a suspension.

CA STATE STANDARD