AQA GCSE Physics Red Shift and the Expanding Universe Worksheet

What is covered

Questions and skills covered

The worksheet contains 6 pages of printable questions. A separate 6-page solutions PDF makes it easy to mark, review or share answers after the activity.

• Red-shift is an increased corresponding wavelength, not dimming or all light becoming red
• Big Bang model initially very small, extremely hot and dense
• Corresponding absorption-feature patterns and confidence from multiple matches
• Both galaxies recede; larger shift indicates faster recession
• Exact wavelength changes and rejecting equal added nm for all model lines
• Consistent fractional wavelength shifts in author model; no red-shift equation required
• One common reference feature across distance survey; greater distance with greater shift and recession speed
• Expanding space/separation is not automatically growing galaxy size
• Backwards expansion supports smaller past, not a direct initial-temperature measurement
• Calibration, independent repeats and peer review with linked confidence reasons
• Distance comparisons do not alone establish speed change with time
• Separate supernova observations from1998 onwards and accelerating recession
• Refining models to account for new and earlier evidence
• Dark mass and dark energy are not fully understood; uncertainty does not erase separate evidence
• Scaffolded six-mark-style observation→inference→limitation argument, original best-fit rubric

About this activity

Link measured wavelength changes to recession and expansion; distinguish observation, inference and claims beyond the data.

Before you start

After teaching4.8.2. Compare corresponding spectral features, subtract nm values and explain qualitative trends. Both-tier GCSE only.