Biology · Investigate

Read an invented growth log

What does a small growth table support, and what cannot it tell us?

Read two complete invented plant-height logs and separate a measured change in the example from an explanation of its cause.

15–25 minutes, or two differences for a first try. More time is optional.

An invented table shows days 0, 2 and 4; plant A has heights 2, 3 and 4 cm; plant B has heights 2, 4 and 5 cm. Total changes are A +2 cm and B +3 cm.
Invented record: same start, different changes. Open full-size diagram ↗

Start here

Use this invented table: day 0, 2, 4; plant A heights 2, 3, 4 cm; plant B heights 2, 4, 5 cm. Their growing conditions are not supplied.

Use your idea or the example below. Talk, write, draw, point or listen first. You can stop after one step.

Try it your way.

  1. Keep units and timing

    Copy or read both rows with the same day headings. These numbers are a constructed practice dataset, not plants measured by Horizon.

  2. Calculate a change

    From day 0 to 4, A changes by 4 − 2 = 2 cm and B by 5 − 2 = 3 cm. Compare changes from the starting height, not only final heights.

  3. Keep cause open

    B has a larger total change in this example. You cannot explain that difference by light, water or treatment because those conditions and repeated samples are missing.

  4. Choose a next question

    Name information that would help a fair comparison, such as the starting type, conditions and repeated records. You can leave the cause unresolved.

One possible version

Invented record: same start, different changes

Day headings are 0, 2, 4. A is 2, 3, 4 cm; B is 2, 4, 5 cm. The table supplies no growing conditions.

  • Both begin at 2 cm. A gains 2 cm by day 4; B gains 3 cm.
  • During days 2 to 4 both gain 1 cm, although their final heights differ.
  • The table supports these differences; it does not identify why they occurred.

Two invented logs cannot establish that a treatment causes growth, predict a species’ growth or represent all plants.

A different way.

Compare the start and finish labels aloud, or draw arrows showing the changes. Growing a plant or plotting a graph is optional.

If you want more.

Plot the three supplied values for each plant on the same labelled axes. Explain why B’s two interval changes are unequal rather than assuming a constant growth rate.

Something to keep?

Did I describe a difference without inventing its cause?

You can keep a question, a sketch or a change of mind. A finished product is optional.

This opens an editable starter in your project tools. It asks before replacing open work. Choosing it does not save or share your work automatically.

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