2nd Grade Science Question of the Day

1. Ice melting and butter melting are reversible because cooling made them hard again. Cooking an egg is not reversible because cooling the cooked egg did not make it raw again. This shows melting can change back, but cooking cannot. (correct answer)
2. Ice melting is reversible, butter melting is reversible, and egg cooking is not reversible. These are the answers because my friend said so. I agree with my friend.
3. Ice melted in the sun and butter melted on bread. The egg cooked in the pan. Then we put things on a plate to cool.
4. Egg cooking is reversible because it can get cold again. Ice melting is not reversible because water spills. Butter melting is not reversible because it is greasy.

Explanation: This question assesses the skill 2-PS1-4: Constructing an argument with evidence that some temperature changes are reversible and some are not. An ARGUMENT has three parts: CLAIM (what you believe—which changes are reversible?), EVIDENCE (observations and test results—what happened when we tried to reverse?), REASONING (why evidence supports claim—this shows it's reversible because...). For reversible changes, evidence shows applying opposite temperature returns material to original state. For not reversible changes, evidence shows even with opposite temperature, material stays changed. The examples are ice melting, butter melting, and egg cooking. REVERSIBLE changes: ice melting and butter melting because water can refreeze and butter can reharden. NOT REVERSIBLE changes: egg cooking because cooling doesn't uncook egg. A complete argument includes claim about each, evidence from observations, and reasoning explaining why. The correct answer is A because it includes all three parts of an argument: CLAIM (states which are reversible and which are not), EVIDENCE (references specific observations from the examples—'cooling made them hard again', 'cooling the cooked egg did not make it raw again'), REASONING (explains why this evidence shows reversibility or not—'this shows melting can change back, but cooking cannot'). The argument uses observations to support the claim. Choice B is incorrect because it provides claim without evidence, using opinion. This error happens when students state opinion without observations and don't connect evidence to claim. To help students construct evidence-based arguments: Teach the three-part structure explicitly using graphic organizer—CLAIM (what I believe), EVIDENCE (what I observed), REASONING (why this supports my claim). Model argument construction: 'I claim ice melting is reversible. My evidence is that when we put the water back in the freezer, it became ice again. This shows it's reversible because we could change it back.' Practice with clear examples first—one reversible, one not reversible—before multiple examples. Sentence frames: 'I claim [change] is [reversible/not reversible] because [evidence]. This shows [reasoning].' Emphasize: Claims need evidence (not 'I think'), evidence must be observations (not opinions), reasoning connects evidence to claim (explains WHY). Use comparison: Show ice melting (observe melting, observe refreezing, conclude reversible) vs egg cooking (observe cooking, try cooling, observe it doesn't uncook, conclude not reversible). Watch for: Students who give claims without evidence, list observations without claims, use 'because I said so' instead of evidence, or don't explain their reasoning. Require all three parts—claim, evidence, reasoning—in every argument.