Earth Science · B4 Science

Lesson notes

Learning Objectives

Indicator: B4.2.1.3.1 - Demonstrate the process of evapotranspiration

By the end of the lesson, learners can:

Demonstrate that plants release water vapour by carrying out the plastic bag experiment on a potted plant.
Explain that transpiration is the release of water vapour from plant leaves, just as humans release water vapour when they breathe out.
Identify the connection between evaporation from the ground and transpiration from plants as together forming evapotranspiration.
Communicate observations from the group experiment clearly, using appropriate vocabulary such as water vapour, droplets, and transpiration.

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Curriculum details

Strand: Cycles (Strand 2)
Sub-strand: Earth Science (2.1)
Content standard: B4.2.1.3 - Show understanding of the roles of condensation, evaporation, transpiration and precipitation in the hydrological (water) cycle
Indicator: B4.2.1.3.1 - Demonstrate the process of evapotranspiration
Suggested placement: Term 1, Week 11 (Week 11 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Science Curriculum (Basic 4-6), 2019, p. 5
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

- Guide learners are guided to breathe out or blow air onto a transparent surface, e.g. a glass or plastic bottle and share their observations.
- Explain to learners that just as humans release water vapour when they respire, so do plants when they transpire.
- Put learners into groups and give each group a young potted plant, plastic wrap bag and a rubber band to undertake the following activities:
(1) Let learners examine the surface of the leaves of the plants and mop off any water droplets on the leaves.
(2) Tie the plastic wrap bag around the plant up to the stem and leave it for an hour. (3) Observe both plant and plastic wrap surfaces. (4) Let learners report on what happens.