A strand of hair has an average mass of 2.17 × 10-5 ounces. A grain of rice has an average mass of 0.002 ounces. How much heavier is a grain of rice than a strand of hair? Express your answer in scientific notation.

To find out how much heavier a grain of rice is compared to a strand of hair, we need to calculate the difference in mass.

Mass of a grain of rice = 0.002 ounces

Mass of a strand of hair = 2.17 × 10^-5 ounces

Difference in mass = Mass of rice - Mass of hair
= 0.002 - 2.17 × 10^-5
= 0.002 - 0.0000217
= 0.0019783

Now, we need to express this in scientific notation.

0.0019783 = 1.9783 × 10^-3

Therefore, a grain of rice is 1.9783 × 10^-3 ounces heavier than a strand of hair.