Author note — to cover

Cover flow as volume per unit time at a constant rate: filling or emptying time from container volume and rate, volume delivered in a stated time, litre and cm3 links, minute and second conversions. Constant rates only; depth-time graphs of odd-shaped containers are Algebra's graph work, gradients the rates-on-graphs group's. Both tiers. (R11, R1)

• Fluency — direct questions on rates of flow, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).