Sunshine State Standard

SC.A.1.4.4

Materials

ï 10% Cobaltous Chloride solution in squeeze bottles ï coffee filters (1 or 2 per student) ï tray or container to hold filters while being saturated with the solution ï drying line on which to hang filters (string) ï green pipe cleaners ï green double leaf cut from crepe paper (optional) ïïïïCAUTION: Younger children should not handle the cobalt chloride solutionïïïï

What to do

ï In a tray, saturate the filter paper(s) with the solution and hang on the "line" to dry overnight. ï Next day, fold the dry filter paper in about fourths and attach the pipe cleaner. Fold the pipe cleaner in half and squeeze the lower 3/4 inch of the flower. Twist the pipe cleaner tightly around the bottom. ï Open the "flower" by separating the folded coffee filter. ï Discuss the shift in equilibrium (color change of the flower) when the weather is humid or it is about to rain. Co(H2O)62+ + 2Cl- = Co(H2O)2Cl22- + 4H2O Co(H2O)62+ is pink Co(H2O)2Cl22- is blue

Additional Information

Submitted by

Jeanne Dyer

Hillsborough County
, Florida
dyerj@mail.firn.edu