Claim, Evidence, Reasoning in Science

Claim, Evidence, Reasoning (CER) Worksheet

Read each scenario carefully. For each scenario, formulate a scientific claim, provide relevant evidence from the scenario, and explain your reasoning, connecting the evidence to your claim using scientific principles.

Scenario 1: A scientist is investigating the effect of different light colors on plant growth. She grows three identical plants: Plant A under red light, Plant B under green light, and Plant C under blue light. All other conditions (water, soil, temperature) are kept the same. After two weeks, Plant A has grown 15 cm, Plant B has grown 5 cm, and Plant C has grown 12 cm.

Claim:

Evidence:

Reasoning:

Scenario 2: A student mixes two clear, colorless solutions, Solution X and Solution Y. Immediately, a yellow precipitate forms at the bottom of the beaker, and the beaker feels warm to the touch. When tested with litmus paper, the resulting solution is neutral.

Claim:

Evidence:

Reasoning:

Scenario 3: Over the past 50 years, the average annual temperature in a specific forest ecosystem has increased by 2°C. Researchers observe a significant decline in the population of a cold-adapted species of moss and an increase in the population of a heat-tolerant insect species. The rainfall patterns have remained consistent.

Claim:

Evidence:

Reasoning: