When my students struggled with accuracy and precision and just plain fought me about writing values with units and significant digits, I knew I had to do something. This activity works! When students are done, they understand why we write values the way that we do and why significant digits or figures are so important. There's some laughter too and a lot of that early in the year grumpiness vanishes.
This activity reinforces the differences between accuracy and precision and how many significant digits are appropriate by determining the number of popcorn kernels in a bag at the front of the room when they only have access to 10.0 kernels and a balance.
Students decide how and what data to collect, determine a value, compare it to that of the class, and identify the sources of error. The class then counts the kernels, each group taking a portion.
This is an excellent activity to demonstrate that 100.0 kernels is not 100 kernels. When students have completed this activity, they understand why significant digits are important in chemistry.
If you have an advanced class, you could also determine the standard deviation.
• Hands on experience
• Works for chemistry or physics
• Cooperative Learning
• Data Collection
• Teacher instructions and set up
• Reinforcement of difficult concepts
• Student handouts
Keywords: precision, accuracy, deviation, error, measure, measurement, unit, units, exponent, calculate, calculation, percent error, percent difference, standard deviation, counting, physics, chemistry.