How Many Drops?
Main Subject Area: Science
Additional Subjects: Mathematics
Duration of Lesson: 90 minutes
Additional Subject Area Standard(s):
Students will collect data on coins and their different properties.
1 penny, 1 nickel and 1 quarter
Bottle of water
Soap (glycerine or dish soap)
Coins Used in Lesson:
Grade Level(s): 6-8
2. Discuss the concept of surface tension as a class.
3. Ask your students to estimate and record how many drops of plain water they think will fit on each of the coins. Have them estimate for each side (obverse and reverse.) Then have the students record their estimates for the number of drops each side of each coin will hold of soapy water.
4. Have your students clean each of the coins and make sure there is no remaining soap.
5. Have your students test their hypotheses by dropping first the plain water on each side of each coin and then the soapy water. They should record their results next to their predictions.
6. Each group of 4 can make a chart of their results. Stem and leaf plots of their predictions and actual results help the students to see their data. Students can then analyze the data for the mean, median, mode, and average.
7. Students should then draw and write conclusions based on their data.
Assessment / Evaluation:
Differentiated Learning Options: