Ontario Grade 8 Science and Technology (Grade 8)
Chapters: 5
1. A. STEM Skills and Connections
A1 STEM Investigation and Communication Skills · A2 Coding and Emerging Technologies · A3 Applications, Connections, and Contributions
- The Scientific Method – The scientific method is the careful way scientists find out how the world works. Observe something, ask a testable question, make a hypothesis (a clear, testable guess), test it with a fair experiment (change one variable, measure one, keep the rest the same), repeat and record data, analyse it, draw a conclusion and share it so others can check. Results that fail the test are useful too: they send you back to a new hypothesis.
- Programming Basics: Sequence, Selection, Loops and Functions – A program is a set of exact instructions a computer follows. Every program is built from three structures: sequence (steps in order), selection (if/else choices) and iteration (loops). Variables store values. Functions group code into reusable, named blocks, which makes programs modular and easier to test, debug and maintain.
- Science, Technology and Society – Science is a way of finding out how the natural world works by asking questions and testing ideas. Technology is the use of that knowledge to make tools, machines and systems that solve problems. Together they change society: food, health, transport and communication. Each technology has benefits and costs for people and the environment, so we weigh them before we decide. Science and technology can solve local problems through the design cycle, and ideas have come from many communities across history, not from one place or one kind of person.
2. B. Life Systems
B1 Relating Science and Technology to Our Changing World · B2 Exploring and Understanding Concepts
- The Cell: Basic Unit of Life – Every living thing is made of cells. Robert Hooke first saw cells in cork in 1665. Cells are prokaryotic (no true nucleus, like bacteria) or eukaryotic (true nucleus). Plant cells have a cell wall, chloroplasts and a big vacuole; animal cells do not. Each organelle has a job. Water enters and leaves cells by osmosis. Cells make new cells by mitosis (growth) and meiosis (sex cells).
3. C. Matter and Energy
C1 Relating Science and Technology to Our Changing World · C2 Exploring and Understanding Concepts
- Density – Density tells how much mass is packed into each unit of volume: ρ = m ÷ V. Its SI unit is kg/m³; in the lab we often use g/cm³ (1 g/cm³ = 1000 kg/m³). Water has density 1 g/cm³. An object less dense than a liquid floats in it; a denser one sinks.
4. D. Structures and Mechanisms
D1 Relating Science and Technology to Our Changing World · D2 Exploring and Understanding Concepts
- Work, Energy and Power – Work is done when a force moves an object: W = F × s, measured in joules (J). Energy is the ability to do work. A moving body has kinetic energy ½mv²; a raised body has potential energy mgh. Energy is never made or destroyed, only changed from one form to another. Power is how fast work is done: P = W ÷ t, in watts. Simple machines like levers and pulleys let a small effort move a big load.
5. E. Earth and Space Systems
E1 Relating Science and Technology to Our Changing World · E2 Exploring and Understanding Concepts
- Water Resources – Almost all water on Earth is salty sea water; only a tiny part is usable fresh water. Growing population, farming, industry and pollution cause water scarcity. Multipurpose dams store water for many uses but also create problems. Rainwater harvesting is an old and simple way to save water.
- Water in the Atmosphere – Air always holds some water as invisible vapour; the amount is called humidity. Absolute humidity is the actual mass of vapour in a volume of air; relative humidity is how full the air is compared with the most it could hold at that temperature. Water becomes vapour by evaporation (taking heat) and turns back to water by condensation (giving heat) when air cools to its dew point. Condensation near the ground gives dew, frost, mist and fog; higher up it gives clouds: cirrus, cumulus, stratus and nimbus. When drops or crystals grow heavy they fall as precipitation: rain, snow, sleet or hail. Rain forms in three main ways: convectional, orographic (relief) and cyclonic (frontal). Rainfall is heaviest near the equator and on windward coasts, and least in subtropical deserts, continental interiors and polar lands.