Safety and Lab Measurement

Which statement describes two unsafe laboratory practices represented in the diagram?

• 
  The flame is too high and the test tube is unstoppered.

• The opening of the test tube is pointed toward the student and the student is not wearing goggles.

• The test tube is unstoppered and the student is not wearing goggles.

• The beaker has water in it and the flame is under the tripod.

A scientist is developing a system to remove harmful bacteria from a contaminated water supply, In order to trap the bacteria and prevent them from going through the filter, she must make sure the pores in the filter are no larger than

• 
  1 nm

• 10 µm

• 1µm

• 100 µm

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

A clear plastic ruler is placed across the middle of the field of view of a compound light microscope. A row of cells can be seen under low-power magnification (100×).

What is the average length of a single cell in micrometers (µm)?

• 10µm

• 100µm

• 2000µm

• 200µm

Tags

NGSS.MS-LS1-1

A diagram of the actual size of a peppered moth wingspan is shown below.

An estimated length of the wingspan could be

• 
  3 centimeters

• 3 grams

• 3 milliliters

• 3 kilometers

What is the approximate length of the earthworm shown in the diagram below?

• 9 mm

• 90 mm

• 10.6 cm

• 106 cm

What is the volume of water represented in the graduated cylinder shown below?

• 10.3 mL

• 13.0 mL

• 14.0 mL

• 15.0 mL

A student measured an earthworm using a metric ruler, as shown in the diagram below.

What is the length of section A?

• 7.6 cm

• 11.6 cm

• 46 mm

• 23 mm