Energy and Control

The Energy and Control strand introduces students to the concept of energy through concrete contexts and investigations, and gradually leads them to a more theoretical consideration of the topic. Some of the aspects of energy examined through concrete experiences include the common forms of energy, its conversions, and its uses. By experimenting with various devices that control the amount of energy dispensed, students will come to understand the relationship between energy consumption and energy conservation.

The topics covered in this strand are:

Grade 1: Energy in Our Lives
Grade 2: Energy From Wind and Moving Water
Grade 3: Forces and Movement
Grade 4: Light and Sound Energy
Grade 5: Conservation of Energy
Grade 6: Electricity
Grade 7: Heat
Grade 8: Optics

As in other strands in the curriculum, investigation of energy begins with an examination of its most common forms, in contexts that are familiar to students, and gradually expands to include more complex forms and global contexts. The exploration of connections with the real world includes such topics as the wise use of energy, energy resources throughout the world, social and economic factors in energy generation, and consumer trends and preferences in energy use.

It is important that students follow established safety practices in all investigations. These practices include:

  • operating safely any appliances used in investigations related to energy (e.g., a hairdryer, an electric fan);
  • incorporating appropriate safety features in devices or products they design and build, and following safe practices while doing so;
  • using all materials (e.g., elastics, springs, light bulbs) in an appropriate and safe manner;
  • following the teacher’s instructions during investigations that involve observation of the sun (e.g., never looking either at the sun directly or at reflections of its rays in a mirror);
  • using safely any device that enables one to study or produce sound (e.g., tapes, microphones, portable cassette players);
  • using proper techniques in handling and disposing of glass;
  • following safety procedures in investigations involving electricity;
  • using appropriate techniques in handling hot materials.

Energy and Control: Grade 7 – Heat

Overview

Students will learn about the causes and effects of heat. They will investigate its properties and how these are related to the measurement of temperature. Students will also be introduced to the particle theory, which can help them to explain their observations and to understand both the relationship between heat and temperature and the concept of heat capacity.

Society’s need to maintain its ability to produce heat is another focus of study. Students will consider ideas about recycling excess or waste heat and about how to make better use of alternative, renewable heat sources to replace non-renewable resources that are being depleted.

Overall Expectations

By the end of Grade 7, students will:

  • demonstrate understanding that heat is a result of molecular motion;
  • identify, through experimentation, ways in which heat changes substances, and describe how heat is transferred;
  • explain how the characteristics and properties of heat can be used, and identify the effect of some of these applications on products, systems, and living things in the natural and human-made environments.

Specific Expectations


Understanding Basic Concepts

By the end of Grade 7, students will:

  • distinguish between the concept of temperature and the concept of heat (e.g., temperature is a measure of the average kinetic energy of the molecules in a substance; heat is thermal energy that is transferred from one substance to another);
  • compare the motions of particles in a solid, a liquid, and a gas using the particle theory;
  • explain how heat is transmitted by conduction, convection, and radiation in solids, liquids, and gases (e.g., conduction: a pot heating on a stove; convection: a liquid heating in the pot; radiation: the air being warmed by heat from the element);
  • describe how various surfaces absorb radiant heat;
  • describe the effect of heating and cooling on the volume of a solid, a liquid, and a gas;
  • investigate and identify factors affecting the rate of temperature change (e.g., mass, nature of liquid) using a constant heat source;
  • describe the effect of heat on the motion of particles and explain how changes of state occur (e.g., from a liquid into a gas or vapour);
  • compare, in qualitative terms, the heat capacities of common materials (e.g., water and aluminum have greater heat capacities than sand and Pyrex);
  • identify systems that are controlled by sensory inputs and feedbacks (e.g., a thermostat);
  • design and build a device that minimizes energy transfer (e.g., an incubator, a Thermos flask).

Developing Skills of Inquiry, Design, and Communication

By the end of Grade 7, students will:

  • formulate questions about and identify needs and problems related to heat (e.g., interactions involving energy transfers), and explore possible answers and solutions (e.g., identify the steps that could be followed to test the effectiveness of the heating system in a home that uses solar energy);
  • plan investigations for some of these answers and solutions, identifying variables that need to be held constant to ensure a fair test and identifying criteria for assessing solutions;
  • use appropriate vocabulary, including correct science and technology terminology, to communicate ideas, procedures, and results (e.g., state the boiling and freezing points of water, room temperature, and body temperature in degrees Celsius; correctly use the terms heat conductor and heat insulator);
  • compile qualitative and quantitative data gathered through investigation in order to record and present results, using diagrams, flow charts, frequency tables, bar graphs, line graphs, and stem-and-leaf plots produced by hand or with a computer (e.g., plot a graph showing the decrease in temperature of various liquids from identical initial temperatures);
  • communicate the procedures and results of investigations for specific purposes and to specific audiences, using media works, written notes and descriptions, charts, graphs, drawings, and oral presentations (e.g., use a diagram to illustrate convection in a liquid or a gas).

Relating Science and Technology to the World Outside the School

By the end of Grade 7, students will:

  • recognize heat as a necessity for the survival of plants and animals;
  • explain how the heating and cooling of the earth’s surface produces air movement that results in all weather effects (e.g., convection currents);
  • describe the water cycle as a process of energy transfer involving convection and radiation;
  • identify different forms of energy that can be transformed into heat energy (e.g., mechanical, chemical, nuclear, or electrical energy);
  • explain how mechanical systems produce heat (e.g., by friction), and describe ways to make these systems more efficient (e.g., by lubrication);
  • describe and explain issues related to heat pollution, including both positive and negative aspects (e.g., industrial processes and generation of electricity cause heat pollution of large bodies of water);
  • explain why heat energy is considered to be the final or end form of energy transformation;
  • identify the purpose of the specialized features of various instruments that are used to measure temperature (e.g., temperature probes provide accurate continuous readings);
  • identify and describe steps that can be taken to conserve energy (e.g., using insulation) and the reasons for doing so (e.g., rising fuel costs);
  • identify the components of a system that are designed to transfer heat energy (e.g., in a room, a house, or a shopping centre) and describe methods for conserving energy within that system.