Powering the Future with… · SHS2 General Science

Lesson notes

Learning Objectives

Indicator: 2.3.1.LI.1

By the end of the lesson, learners can:

Define electrical energy and electrical power in their own words, using correct scientific terminology.
Distinguish between electrical energy and electrical power, stating the SI unit for each (joule and watt respectively).
Calculate electrical power using the formula P = IV and electrical energy using the formula E = Pt, given appropriate values.
Read an electricity meter and calculate the energy consumed over a given period, expressing the result in kilowatt-hours (kWh).
Relate electrical energy and power to the operation of common appliances in their homes and school, explaining why higher-wattage appliances consume more energy.

This lesson opens the topic of electrical energy and power. Learners already know from JHS that electricity is a form of energy produced from sources such as batteries, generators, and the national grid. They have constructed simple circuits and know the meanings of current, voltage, and resistance. This lesson builds on that foundation by introducing the quantitative relationship between electrical energy, power, current, and voltage. The principle of transformers is scheduled for the next lesson, so it is not covered here.

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Curriculum details

Strand: Vigour Behind Life (Strand 3)
Sub-strand: Powering the Future with Energy Forms (3.1)
Content standard: 2.3.1.CS.1 - Demonstrate understanding of electricity as a form of energy. 2.3.1.LO.1 Construct and analyse electric circuits in determining resistance, potential difference, and current and distinguish between step-up and step-down transformers.
Indicator: 2.3.1.LI.1 - Explain the concept of electrical energy and power.
Suggested placement: Semester 2, Week 1 (Week 21 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: NaCCA curriculum document, p. 72

Exemplars (from the NaCCA curriculum)

- Review previous knowledge of sources of electrical energy through collaborative learning by using PHET simulations, pictures and videos. Ensure groups are manageable and supervised appropriately.
- Put learners in mixed-ability groups to construct functional electric circuits and use them to calculate current, resistance and voltage while providing positive remarks to group work.
- Demonstrate how meter reading is carried out and how to calculate energy consumed with meter reading and communicate their findings in groups.
- Using inclusive and differentiated learning, the teacher demonstrates to learners how appliance troubleshooting at home or school is done and dispels misconceptions and stereotypes about males' and females' abilities in handling electricity.
- Learners research on how to conduct energy audits, energy savings plans, and safety devices used in electrical circuits.
- Through experiments, lead learners to demonstrate the electrical conductivity of different liquids (distilled water, drinking water, lemon juice, sugar solution, coconut oil, vinegar, and other appropriate liquids)
- Use models, pictures and charts to help learners make their own cells through projectbased teaching.
- Assist learners to explain the heating effect of electric currents using Talk for Learning approaches.
NOTE: Learners should not taste the liquids during the activities.
Teaching and Learning Resources:
- PHET simulations, pictures, videos, charts and models showing sources of electrical energy.
- LEDs, bulbs, dry cells, connecting wires and switches.
- Meter, Videos, pictures and charts showing meter readings.
- Testers, sockets.
- Metal pins, rubber cap of injection bottle, connecting wires, distilled water, drinking water, vinegar, sugar solution and lemon juice.
- Pictures and charts of step-up and step-down transformers.
Assessment (2.3.1.AS.1). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning; Level 4 Extended critical thinking and reasoning.