lesson
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Imagine dropping an antacid tablet into cold water and another into hot water — one vanishes in seconds, while the other slowly fizzles away.
In science, saying "hot water dissolves it faster" is not enough. You need an airtight argument that connects what you observed to the fundamental laws of science.
How do scientists convince the world that their conclusions are correct?
The Three Parts of CER
A CER argument organizes scientific thinking into three distinct components: a claim, evidence, and reasoning.
📊Create an interactive visual framework showing the three blocks of CER stacked like building blocks of a scientific explanation. Block 1 (top): 'Claim - The Answer' with an icon of a bullseye/flag. Block 2 (middle): 'Evidence - The Data' with an icon of a ruler/bar chart. Block 3 (foundation): 'Reasoning - The Science Principle' with an icon of a brain/gears. Each block has a brief definition card with color coding: Claim (blue #2563eb), Evidence (green #16a34a), Reasoning (purple #9333ea). Smooth hover elevation effect, clean typography, responsive layout for 350px width.
A claim is a single, direct sentence that answers your research question without using words like "because" or "I think".
Evidence consists of specific, measurable facts from observations or experiments, such as numbers, units, and percentage changes.
Reasoning is the scientific principle, rule, or mechanism that explains why that specific evidence proves your claim.
What does a complete CER argument look like when analyzing real lab data?
Worked Example: Dissolving Rates
A student investigates how water temperature affects dissolving time by dropping identical 2.5 g antacid tablets into 200 mL beakers at different temperatures.
📊Create a clean comparison card displaying the experiment data: 3 beakers labeled with temperature and dissolving time. Beaker 1: Cold (20°C) -> 54 seconds. Beaker 2: Room Temp (40°C) -> 27 seconds. Beaker 3: Hot (60°C) -> 12 seconds. Below the beakers, show a mini bar chart plotting time vs. temperature with a clear downward trend. Text in #1e2945, accent bars in #2563eb, clean borders.