What can cause differences in weight when using a digital balance?

Question

I have this practice question but I don’t understand it, so two students were asked to find the weight of a penny on a digital balance. The first student (mike) found the weight was 0.001 grams and the second student (mindy) found the weight was 4.3.

 

For mindy, I’d say she didn’t reset the values of the scale before measuring? But I don't know for mike.

The question asks what each student may have done incorrectly.

Answer 1

One explanation is a systematic error, where this can occur because of a mechanical error or design. The word "tare" means resetting the scale to zero with the container on the scale.