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Densities of liquids
We have been learning about density recently in my middle school science classroom. Most previous work was done using mass and volume to calculate density. This activity was designed to help students identify how density differences in liquids can be used to sort the liquids. Teacher preparation was kept to a minimum. Five different liquid solutions were prepared. Each solution contained corn syrup and water. The solutions were each made in separate 800 ml beakers. The least dense solution had about 75 ml corn syrup added, the second least dense had about 150 ml corn syrup, the middle solution was about 220 ml corn syrup, the second densest contained just over 275 ml corn syrup, and the densest had almost 350 ml corn syrup in it. All beakers were filled up to approximately 700 ml using tap water. The corn syrup was dissolved in the water of each beaker. Next I added quite a bit of food coloring into each beaker (probably close to 25 drops in each.) NOTE: from experience, I know better than to make the layers fit Roy G. Biv as the kids figured that out too quickly.
Students were given small amounts of each liquid (close to 20 ml) along with a dropper for each liquid. Each group of students had 10 small test tubes for experimenting in . The protocol was to experiment with ONLY two liquids at a time and keep detailed observations of the results. Students were reminded they should determine which of each liquid combination was the densest. The students were to ONLY use 9 of their test tubes in this testing.
As a FINAL challenge the students were asked to try and get all 5 liquids in order from densest at the bottom to least dense at the top of their final (10th) test tube.
Students were given small amounts of each liquid (close to 20 ml) along with a dropper for each liquid. Each group of students had 10 small test tubes for experimenting in . The protocol was to experiment with ONLY two liquids at a time and keep detailed observations of the results. Students were reminded they should determine which of each liquid combination was the densest. The students were to ONLY use 9 of their test tubes in this testing.
As a FINAL challenge the students were asked to try and get all 5 liquids in order from densest at the bottom to least dense at the top of their final (10th) test tube.
2 Comments
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Comment by Glen Westbroek on February 7, 2009 at 10:59pm - I'd not thought about doing it as a competition. That could be fun in determining a winner. Thanks for the suggestion.
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Thanks for the post.