NATURE OF SCIENCE: Errors in measurement

Taking reading in a burette by not keeping it at the eye level gives rise to

• systematic error

• random error

True or False?

Repeating a reading never removes the systematic error.

• True

• False

Which of these is NOT true for systematic errors?

• They arise due to errors in the measuring instruments used.

• Repeating the observations or increasing the sample size can eliminate them

• They are reproducible inaccuracies that are consistently in the same direction.

• They arise from misinterpretation of procedure

Repeated measurements of a quantity can reduce the effects of

• both random errors and systematic errors

• neither random errors nor random errors

• random errors

• systematic errors

Olu is testing the effects of three different liquids on plant growth. Olu needs to measure out 19 mL of each liquid for her investigation. Which of the following tools should she use to get the most accurate measurements?

THINK: What tools do we use to measure volume?

• A beaker with increments of 20 mL

• A beaker with increments of 10 mL

• A graduated cylinder with increments of 1 mL

• A graduated cylinder with increments of 5 mL

Dennen needs to measure out 3 mL of liquid for an investigation. Which of the following tools would he use for the most accurate measurement?

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Which of the following tools will provide the most accurate measurement of the mass of a small object?

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Shiloh wanted to measure the length of a plastic spork from the cafeteria. She lined up the spork next to the ruler as shown below and observed the length of the spork. She recorded a length of 9cm.

THINK: What are the three things all scientists do when they measure?

• She recorded the wrong units.

• She needed to choose a larger ruler.

• She used the wrong type of ruler.

• She lined up the end of the spork at the wrong place on the ruler.

Miguel wants to use an electric scale to find the mass of a rock. He makes sure there are no objects sitting on the pan of a scale. Miguel turns on the scale, and this is what he sees:

Miguel made a measurement error and his measurement is incorrect. What did Miguel do incorrectly?

• Miguel forgot to zero (tare) the scale

• Miguel forgot to turn on the scale

• Miguel forgot to place the object on the scale

• Miguel forgot to read the final measurement on the scale

Kacey needed to measure the amount of liquid in a graduated cylinder. He used a graduated cylinder that measured in milliliters. Kacey found that the volume of the liquid was 25 milliliters.

Unfortunately, Kacey made a measurement error and her measurement is incorrect. What did Kacey do incorrectly?

• He looked at the top of the meniscus instead of the bottom of the meniscus.

• He used a graduated cylinder instead of a beaker.

• He used the wrong units.

• He forgot to put an object in the beaker and calculate the amount of displaced water.