Question

1. judy did an experiment to see what type of metal conducts electricity best. what should she do to be sure that her results are correct? a. test different types of metal b. do the experiment several times c. make a graph to show her results d. check to see whether other students did the same experiment 20. michael rides a bike made by company a. luis rides a bike made by company b. how can michael and luis determine in a scientific way whose bike has tires that last longer? a. read information about the tires from each manufacturer. b. ask ten classmates who ride each bike which tires last longer. c. each student should ride their own bike for 25 days, then compare the tires. d. use a machine to test the bikes in the same way for 25 days, then compare the tires.

Explanation:

For question 19, repeating an experiment multiple times helps to reduce random errors and increase the reliability of results. For question 20, using a machine to test the bikes in the same way for a set period controls variables and provides a more scientific comparison.

Answer:

1. B. Do the experiment several times
2. D. Use a machine to test the bikes in the same way for 25 days, then compare the tires.