Ontario Grade 9 SNC1W Science (Grade 9, De-streamed)
Chapters: 5
1. A. STEM Skills, Careers, and Connections
A1 STEM Investigation Skills · A2 Applications, Careers, and Connections
- 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.
- Career Planning: From Knowing Yourself to Your First Job – Career planning has five steps. 1) Know yourself: interests, skills and values. 2) Explore career families and find out the work, study needed, pay and demand. 3) Plan a pathway with SMART goals and a plan B. 4) Search for jobs with a CV, cover letter, digital portfolio and interview practice. 5) Make the move from school to work and keep learning, because careers change over a lifetime.
2. B. Biology
B1 Relating Science to Our Changing World · B2 Investigating and Understanding Concepts
- Ecosystem, Food Chains and Energy Flow – An ecosystem is all the living things in a place plus the non-living things around them, working together. Energy enters as sunlight, passes one way up a food chain, and only about 10% moves to each next level.
3. C. Chemistry
C1 Relating Science to Our Changing World · C2 Investigating and Understanding Concepts
- Environmental Stewardship: Caring for the Planet as We Use Technology – Environmental stewardship means using the Earth's resources carefully so they last, and fixing harm where we can. Every product, from a phone to a hospital machine, has a life cycle: raw materials, making, transport, use and end of life. Each stage uses energy and makes waste. Good stewards keep products longer, choose efficient machines, follow the waste hierarchy (refuse, reduce, reuse, recycle, then dispose), send e-waste to proper recyclers and support laws and company practices that protect nature. Technology can harm the environment, but it can also help: solar panels, LEDs and smart sensors cut waste.
- Structure of the Atom – An atom has a tiny, heavy, positive nucleus made of protons and neutrons. Electrons move around it in fixed shells K, L, M, N. The number of protons (Z) tells the element; protons + neutrons give the mass number (A). Outer electrons decide valency. Isotopes share Z; isobars share A.
4. D. Physics
D1 Relating Science to Our Changing World · D2 Investigating and Understanding Concepts
- Electric Current, Potential Difference and Electric Circuits – Electric current is the rate of flow of charge, I = Q/t, measured in amperes with an ammeter joined in series. Potential difference is the work done to move a unit charge between two points, V = W/Q, measured in volts with a voltmeter joined in parallel. Charge flows only in a closed circuit.
- Ohm's Law – At constant temperature, the current through a conductor is directly proportional to the potential difference across it: V = I × R. R is the resistance, measured in ohms (Ω); 1 Ω = 1 V/1 A. The V–I graph of an ohmic conductor is a straight line through the origin.
5. E. Earth and Space Science
E1 Relating Science to Our Changing World · E2 Investigating and Understanding Concepts
- Space Exploration – Space exploration means sending rockets, satellites, probes and people beyond Earth's air. Rockets rise by pushing gas down (action–reaction). At about 7.9 km/s sideways a craft keeps falling around Earth in orbit; at 11.2 km/s it escapes. Since 1957 space has been a place of rivalry and cooperation, and it gives us weather forecasts, navigation, communication and new science.
- Stars and Galaxies: From Starlight to the Big Bang – Everything we know about stars comes from their light. Splitting starlight into a spectrum shows dark lines that tell us which elements a star has; the colour tells us its temperature (blue = hot, red = cool) and stars are sorted into classes O B A F G K M. The H-R diagram plots true brightness against temperature: most stars, including the Sun, lie on the main sequence, with giants top right and white dwarfs bottom left. A star is born in a nebula and its mass decides its life: a Sun-like star becomes a red giant and then a white dwarf; a star of more than about 8 solar masses becomes a supergiant, explodes as a supernova and leaves a neutron star or black hole. Stars gather in galaxies, which are spiral, elliptical or irregular. Distances are huge, so we use the astronomical unit, the light-year and the parsec. Galaxies are moving apart, faster when farther (Hubble's law), which together with the cosmic microwave background supports the Big Bang about 13.8 billion years ago.