Science - Investigations and Repeated Trials

​REPEATING SCIENTIFIC INVESTIGATIONS

​Recognize and explain that when scientific investigations are carried out, the evidence produced by those investigations should be replicable by others. 

​You will need your

​I. Experiments need to be REPEATED

• scientists must keep detailed records in order to be able to REPEAT

• MORE Repeated Trials = More reliable results

​II. Reliable and Replicable

• ​Reliable : able to be trusted

  • If results of an experiment are consistent across many repetitions

• Replicable: able to be copied

  • other scientists follow the procedure EXACTLY

  • other scientists question, discuss and check each other's evidence and explanations for validity

Multiple Choice

Avi is comparing two brands of batteries. He uses two identical flashlights to see which battery lasts longer. What is the best reason for this experiment to be repeated?

• to check whether the results are consistent

• to make sure the flashlights were not broken

• to check that no one turned off one of the flashlights

• to make a prediction about a different brand of battery

Multiple Choice

Lauren is investigating the way plant stems transport liquids. She puts a white flower in a glass of water and then adds red food coloring to the water. She concludes that the

colored water moved up the stem to the flower petals. If the conclusion is correct, what should happen if Lauren repeats the experiment?

• She should get the same results

• She will follow a new procedure

• She should use a different kind of flower

• She will probably make different observations

Multiple Choice

Manuel and Chris are investigating the kinds of flowers that attract butterflies. They took a survey of people who work at local garden shops and nurseries. What is the best reason they should take careful notes about how they carry out their survey?

• so they do not leave out any steps

• so they can take out answers they do not like

• so their conclusions can be checked with another survey

• so they can decide whether they want to finish

  their investigation

Multiple Choice

Edena compares the time of one back-and-forth swing for each of five pendulums. She concludes that the longest pendulum swings back and forth the most slowly.

However, she does not record the lengths of the strings, the times, or the masses she uses.

What is the best reason that the results of Edena’s experiment are not very useful?

• She did not decide if her hypothesis is supported.

• She did not write down a prediction before beginning.

• The experiment cannot be repeated to confirm her results

• The experiment should have tested different types of string

Multiple Choice

Allison is studying constellations. On a clear night, she sketches the constellations she sees at different times. She concludes that the constellations appear to move in the

night sky. If this conclusion is correct, what should happen if Allison repeats the investigation?

• She should reach a new conclusion

• She should make similar observations

• She should choose different constellations

  to study.

• She should form an opinion about her favorite

  constellation.

Multiple Choice

Yoshi is investigating the way surface area affects the evaporation of water. She pours the same amount of water into a shallow dish and into a tall, narrow jar. She

measures the volume of water left after a few days. What is the best reason for Yoshi to record her steps and results carefully?

• The experiment will still work if it is cloudy

• She does not need to do the experiment again

• No one else will have to carry out the experiment

• Another student can repeat the experiment to check the results

Multiple Choice

Harry is investigating magnets. He wants to find out whether a magnet can pick up a paper clip through paper, glass, and other materials. What is the best reason for recording his steps and results carefully?

• No one will question his conclusions

• Someone else can repeat the experiment

• People might think he just made up the results

• He may not remember what materials he tested

Multiple Choice

Lauri is comparing the forces needed to pull a toy car up a ramp at different heights. She uses stacks of books to change the height of the ramp and then she measures the

force with a spring scale.

What is the best reason for several other students to repeat

this experiment?

• to change the results

• to make a new prediction

• to get enough data for a graph

• to check that the results are correct

Multiple Choice

Debbie is experimenting with static electricity. She rubs a balloon on the carpet and then records how long the balloon sticks to the wall.

What is the best reason another person should repeat this experiment?

• to make sure the results are accurate

• to find out if static electricity is dangerous

• to check that she did not use glue or tape

• to check that she recorded her data correctly

Multiple Choice

Fred is experimenting with electrical circuits. He connects three bulbs to a battery using this set up. What is the best reason for Fred to make an accurate drawing of his experimental set up?

• so he will not get an electrical shock

• so that all three bulbs will light up together

• so someone else can repeat the experiment

• so he can make a prediction before he starts

Multiple Choice

Vanka compared the water temperature in two beakers placed on different colors of paper. He found the temperature was higher in the beaker placed on dark paper.

Connie repeated Vanka’s experiment and got different results.

Which statement describes what most likely happened?

• Vanka is right, and Connie is wrong

• Connie is right, and Vanka is wrong

• One student made a mistake recording the data.

• One student did not follow established safety procedures

Multiple Choice

Marshall adds ice to a jar of water and closes the top. After some time passes, he sees that drops of water form on the outside of the jar.

What is the best reason for another person to do the same experiment again?

• to try another procedure

• to get the results more quickly

• to see if the results are the same

• to make more careful measurements

Multiple Choice

Hamil is investigating how adding salt to water changes the amount of time it takes water to boil. He concludes that it takes longer for the water containing salt to boil.

However, he does not record how long it took for the water to boil or the amounts of water and salt he used.

What is the best reason the results of Hamil’s investigation are not very useful?

• He did not record a prediction.

• Someone else might want to test a

  different variable

• He did not use the correct safety procedures.

• Someone else could not repeat his experiment

  to check his results

Multiple Choice

Chim drew this picture of what he observed after putting a pencil in a glass of water.

He concluded that the light rays were bent as they passed from the air to the water.

Why should another student do the same experiment again?

• to make a new prediction

• to use pencils of different lengths

• to try water at a different temperature

• to check that the results are the same

Multiple Choice

Suzanne is experimenting to find out what makes some objects float and others sink.

She fills an aquarium with water and tries many different objects. She tries to use

objects with about the same volume.

What is the best reason for Suzanne to describe the objects accurately?

• so she can make a graph

• so her experiment can be repeated

• so she does not use two objects that are

  the same

• so she can compare her conclusion

  with her prediction