Need for Repeated Trials - SC.5.N.1.3

Judy did an experiment to see what type of metal conducts electricity best.

What is the best way for her to be sure that the results are correct?

• test different types of metal

• do the experiment several times

• make a graph to show her results

• check to see whether other students did the same experiment

When a scientist performed an experiment, she did not get the results she expected.

What should she do?

• change the results

• assume her results are correct

• assume her results are incorrect

• do the experiment again to test her results

What is the best reason why Basil should record all the steps of his experiment in his report of the results?

• to test each type of fruit juice the same way

• to be sure the experiment can be repeated to confirm the results

• to be sure he uses the same amount of fruit juice for each test

• be sure he does not repeat the test using the same fruit juice twice

Rosario did only one trial of her experiment. What is the best reason why she should repeat her experiment?

• to get a better grade

• to check her conclusions

• to be sure she used the fewest possible steps

• to see whether another method gives the same results

Marshall does an experiment to see what type of insulator keeps a cup of boiling water hot the longest.

What is the best way for Marshall to be sure that his results are accurate?

• do more trials of the experiment

• use different materials as insulators

• record the data in two types of graphs

• form conclusions based on his observations

Scientists at a plastics factory have found a new type of plastic. They are doing experiments to learn about its properties.

Why will the scientists repeat their experiments?

• to test different properties

• to make sure the data they collect are correct

• to try to color the plastic different colors

• to check that this plastic is not the same as another plastic

Ponciano and his brother tested the amount of salt in two samples of ocean water from the same location.

What is the best reason why they should test more samples of ocean water from this location?

• to make sure the water had not gotten warmer

• to make sure their measuring cups were the same

• to make sure they get the same results when they repeat their test

• to change their results if they don’t think they got correct results the first

  time

Some students made different types of paper airplanes. They tested the planes to

see which flew farthest.

Why do the students need to do several trials of the experiment before analyzing the results?

• to see how the airplanes fly after they have landed a few times

• to have everyone get a chance to launch the airplanes

• to get a more accurate measure of how far each plane can fly

• to try the airplanes both indoors and outdoors

A class was divided into 6 groups. Each group tested the same foods to see which ones contained fat. One group’s results were different from those of the other groups.

What would be best for that group to do next?

• change their results to match those of the other groups

• repeat the experiment and see whether they get different results

• check their measuring tools to see whether they are accurate

• discard their results and assume they made a mistake

Jay did an experiment to show the flow of liquid through the membrane surrounding an egg. These are the materials he used in his experiment:

Materials

1 pint jar

1 cup of vinegar

1 raw egg in its shell

tongs

What is the best reason for Jay to list the materials as part of his plan?

• so that his experiment can be repeated

• so that he remembers to return anything he borrows

• so that he knows what he needs when he goes shopping

• so that he can be sure that he does not leave anything out