Question

use the scaffold below to critique the two possible claims and to construct the strongest argument based on the evidence.
investigation question: is our sun releasing energy due to chemical or nuclear reactions?
possible claim #1
the sun is releasing energy due to...
possible claim #2
the sun is releasing energy due to...
evidence for claim #1
the evidence that supports this claim is...
evidence for claim #2
the evidence that supports this claim is...
evaluation and critique
use your science knowledge to critique claim #1 by considering the quality and strength of the evidence.
evaluation and critique
use your science knowledge to critique claim #2 by considering the quality and strength of the evidence.
decide which claim you think is best supported. write a scientific argument that includes the following:

• the investigation question;
• the claim you think is best supported by the evidence;
• a summary of the evidence that supports your claim;
• the critique of your claim compared to the other claim based on the evaluation of the evidence.

Explanation:

The scaffold requires analyzing two claims about the Sun’s energy source. Claim #1 (chemical reactions) is unsupported because chemical reactions release far less energy than the Sun emits over its 4.6-billion-year lifespan. Claim #2 (nuclear reactions, specifically fusion) is supported by evidence like the Sun’s long-term energy output matching fusion’s energy yield, and the detection of neutrinos (byproducts of fusion) from the Sun. A strong argument integrates the investigation question, the supported claim, evidence summary, and critique of the alternative claim.

Answer:

Scaffold Completion:

• Possible Claim #1: chemical reactions
• Possible Claim #2: nuclear fusion reactions
• Evidence for Claim #1: (No valid evidence—chemical reactions cannot sustain solar energy)
• Evidence for Claim #2: 1. Sun’s energy output (~3.8×10²⁶ W) aligns with hydrogen fusion in its core; 2. Neutrinos (fusion byproducts) detected from the Sun; 3. Fusion explains the Sun’s 4.6-billion-year lifespan.
• Evaluation of Claim #1: Chemical reactions (e.g., combustion) release ~10⁶ J/kg, insufficient to power the Sun for billions of years.
• Evaluation of Claim #2: Fusion (4×10¹⁴ J/kg from hydrogen to helium) provides enough energy for the Sun’s lifespan; neutrino detection confirms fusion occurs.

Strongest Argument:

Investigation Question: Is our Sun releasing energy due to chemical or nuclear reactions?
Best-supported claim: The Sun releases energy via nuclear fusion reactions.
Evidence summary: Fusion produces ~4×10¹⁴ J/kg (100 million times more than chemical reactions), matching the Sun’s 3.8×10²⁶ W output over 4.6 billion years; neutrinos (fusion byproducts) are detected from the Sun.
Critique: Chemical reactions lack the energy density to sustain solar energy. Fusion is the only process consistent with observational evidence.