In this lab experience, students float a paper clip on the surface of water and then use soap to change the surface tension, finally counting how many drops of water they can balance on a penny’s face. Students learn that the intermolecular interactions between water molecules give rise to surface tension and that disrupting these interactions by the introduction of a surfactant changes the surface tension.
Safety:
Before conducting the lab, review the safety precautions on the student page with the class. Then discuss any safety precautions that are specific to your science laboratory or classroom.
Materials Included in Kit
Consumable:
Construction paper, black, half sheets, package of 10, 2
Cotton swabs, package of 75
Paraffin wax, 4 oz blocks, 4
Soap solution, 70 mL
Pipets, 20
Non-Consumable:
Paper clips, box of 100
Petri dishes, 30
1-800-452-1261
