A marine biologist writes two lines in her notebook at a tide pool. Line 1: 'Nine of the 12 sea stars I counted were on shaded rock.' Line 2: 'Sea stars avoid direct sunlight.' How are the two lines best classified?

Four entries appear in a field notebook after a morning at a pond. Which entry is an inference rather than an observation?

A student examines a leaf under a microscope and writes four sentences. Which one is an observation?

A lab notebook reads: 'The seedling is 24 cm tall and has three yellow lower leaves. The soil is low in nitrogen.' Which part of the entry is the inference, and why?

Two lab partners record the same beaker of pond water. Ana writes '14 Daphnia in a 10 mL sample.' Ben writes 'This water is healthy.' What is the key difference between the two records?

A researcher finds gnawed bark on ten aspen trunks near a river and writes: 'Beavers have been feeding here this winter.' Why is this statement an inference?

A biology textbook states: 'All living things are made of one or more cells, cells are the basic unit of life, and all cells come from existing cells.' What is this statement?

A student writes: 'If bean seedlings are watered with 2% salt solution, then their average height after 14 days will be less than that of seedlings watered with distilled water.' What is this statement?

In a genetics chapter a student reads: 'The two alleles for a trait separate from each other during the formation of gametes.' Mendel stated this after counting thousands of offspring. What is this statement?

A classmate says that evolution by natural selection is 'only a theory, so it has not been proven yet.' Which statement corrects the way the word theory is used in science?

How is a scientific law related to a scientific theory?

A student wants to investigate aquarium fish and lists four questions. Which one can be tested by an experiment?

A gardener claims, 'Compost makes tomato plants healthier.' Which rewrite turns the claim into a form an experiment could test?

A science fair judge rejects one project question as untestable. Which question is it, and why?

An accepted explanation of a cell process has 30 years of support. A group then publishes results it cannot account for, and three other laboratories repeat the work and get the same results. What should happen to the explanation?

One laboratory reports a single result that conflicts with a widely supported theory. What is needed before the theory is revised?

New imaging methods let researchers measure a process far more precisely than before. The measurements match an accepted explanation in most respects but show one step happens in a different order. What is the likely outcome?

What makes an explanation scientific rather than unscientific?

A researcher predicted that a soil fungus would slow the growth of a weed. In her trial the weeds grown with the fungus reached the same height as those grown without it. What is the appropriate next step?

Halfway through an enzyme experiment a student notices that the tubes in the control group sat on a warm windowsill while the treated tubes stayed on the bench. What should she do?