Scale a supplied orbital-cycle interval

Supplied materials

• All measurements and observations below are supplied classroom examples. They are not data from actual learners or a claim about a particular real site.
• Paper or browser document; an ordinary calculator is optional.
• Rule: Elapsed model days equal period in days multiplied by cycle fraction. Formula: a*b. Variable key: a = model period (days), b = cycle fraction
• Distinct worked inputs and result: A distinct simplified cycle is 24 days: one quarter is 24×0.25=6 days.
• Assessment case 1: Supplied case 1: model period (days)=28; cycle fraction=0.25, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
• Assessment case 2: Supplied case 2: model period (days)=28; cycle fraction=0.5, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
• Assessment case 3: Supplied case 3: model period (days)=32; cycle fraction=0.25, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
• Assessment case 4: Supplied case 4: model period (days)=32; cycle fraction=0.75, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
• Assessment case 5: Supplied case 5: model period (days)=40; cycle fraction=0.5, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
• Assessment case 6: Supplied case 6: model period (days)=40; cycle fraction=0.25, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?

Learn the idea

Fractions of a stated period represent elapsed model time. The fictional simplified cycle does not make every observed phase occur at an exact quarter-day count.

Elapsed model days equal period in days multiplied by cycle fraction. The formula in the supplied model is a*b. Variable key: a = model period (days), b = cycle fraction. Use the supplied simplified period. A fraction of a cycle is not a new astronomical constant.

A distinct simplified cycle is 24 days: one quarter is 24×0.25=6 days. Real phase timings need observation and orbital detail. Track the quantity and unit before calculating. Explain the meaning of a positive, negative or fractional result when relevant. A numerical answer supports the stated model calculation; broader claims require the additional measurements and assumptions described here.

1. Name the measured quantities and their units before substituting values.
2. Write the stated rule and use the variable key to match each symbol to its explicitly named quantity.
3. Calculate each supplied case separately, keeping intermediate arithmetic and the result unit.
4. Explain the result in context and identify the assumption that would invalidate direct use of the rule.

Check your reasoning

Your answer is temporary and is not saved to an account. Download your current answer before leaving or reloading. Written work on paper or in another app stays in your own file.

Take it further

Changed-input task: use the same stated model with model period (days)=29; cycle fraction=0.25. Expected result: 7.25 days. Explain what changes and keep this assumption: Real phase timings need observation and orbital detail.

Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.