Grade 9 and 10 Physics in Ontario: Electricity, Optics and Getting Ready for SPH3U

Ontario students do not take a physics course until Grade 11. Before SPH3U, physics is one unit inside each year's science course: electricity in Grade 9 Science (SNC1W) and light and geometric optics in Grade 10 Science (SNC2D). So if you are looking for help with Grade 10 physics, the optics unit is what you are looking at.

The two units look unrelated, and in a sense they are. What links them to Grade 11 Physics, SPH3U, is less the topics than the habits: treating a formula as a model of a relationship, drawing an accurate diagram before calculating anything, and keeping track of units. SPH3U expects all three from its first unit.

Grade 9 physics: electricity (SNC1W)

The physics strand of SNC1W is called Principles and Applications of Electricity. By the end of it, students should be able to:

• explain how electric charges behave in static and current electricity, and connect that behaviour to the structure of the atom

• test which materials conduct electric charge and which hold it

• identify the parts of a DC circuit, and the symbols and SI units for current, potential difference and resistance

• investigate how current, potential difference and resistance relate, build a mathematical model of that relationship, and use it to calculate values in real situations

• build series and parallel circuits and compare how current, potential difference and resistance behave in each

• tell electricity apart from electrical energy, and work out the efficiency of electrical devices

That mathematical model is the relationship most students know as Ohm's law (V = IR). SPH3U uses it by name in its Electricity and Magnetism unit. The full Grade 9 course is mapped in our SNC1W course guide.

Grade 10 physics: light and geometric optics (SNC2D)

The physics unit of SNC2D is Light and Geometric Optics. Students:

• describe types of light emission (incandescence, fluorescence, bioluminescence and others) and the regions of the electromagnetic spectrum

• investigate the laws of reflection with plane and curved mirrors, and draw ray diagrams to summarize what they find

• predict the location, orientation, size and type of images formed by mirrors and converging lenses, using ray diagrams and algebraic equations

• investigate refraction, calculate the speed of light in different media from the index of refraction, and explain total internal reflection

• explain how optical devices such as cameras, telescopes and microscopes work, and how effects like mirages and rainbows happen

The rest of the Grade 10 course is mapped in our SNC2D course guide.

The skills SPH3U assumes

SPH3U covers kinematics, forces, energy and society, waves and sound, and electricity and magnetism. Here is how Grades 9 and 10 feed into it:

Circuits carry straight over. SPH3U's Electricity and Magnetism unit analyses series, parallel and mixed circuits with Ohm's law and Kirchhoff's laws. Students who understood SNC1W circuits start that unit ahead. Students who memorized them start over.

Efficiency comes back. The efficiency calculations from SNC1W return in SPH3U's Energy and Society unit, alongside work and power.

Ray diagrams build the diagram-first habit. Optics is often the first time a student has to draw something accurately before any number appears. SPH3U's Forces unit runs on the same habit with free-body diagrams, and its Kinematics unit works in one and two dimensions with vector diagrams.

Equations as relationships. Solving an optics equation or V = IR for an unknown is the same algebra every SPH3U kinematics question uses. Rearranging before substituting is the habit to build now.

Light comes back in Grade 12. Geometric optics is not part of SPH3U, but SPH4U has a full unit on the wave nature of light, where refraction returns.

Where students lose marks

Series versus parallel. Current and potential difference behave differently in the two circuit types. Students who memorize a table of rules instead of picturing how charge flows mix them up under test pressure.

Freehand ray diagrams. A ray diagram is a measuring tool. Rays drawn without a ruler, or that miss the focal point, put the image in the wrong place before any equation is used.

Describing the image. Every mirror and lens question wants four judgements: location, orientation, size, and real or virtual. Students who give two or three of the four leave easy marks behind.

Units and symbols. Mixing up potential difference (volts) and current (amperes), or forgetting to convert milliamperes, costs full marks on otherwise correct work.

Most of these errors are invisible in homework that only checks the final answer. A Go2Grad tutor follows the method, from how the circuit is drawn to where each ray goes, and corrects it at the step where it slips. Request a tutor and we will match you within 2 to 3 days, or meet our tutors first.

How to get ready for SPH3U

• Redraw three circuits from memory. A series circuit, a parallel circuit and a mixed one. Predict how current and potential difference split in each before you check.

• Practise ray diagrams with a ruler. Place an object at different distances from a converging lens and describe each image in words: location, orientation, size, real or virtual.

• Rearrange before you substitute. Solve the equation for the unknown symbol first, then put in numbers with units. SPH3U kinematics depends on this.

• Keep Grade 10 math moving. SPH3U's kinematics leans on algebra and graphing from the start, and two-dimensional motion uses vector diagrams, which are easier when right-triangle trigonometry is solid.

• Use the summer well. Our summer prep guide for SPH3U and MCR3U has more on preparing for Grade 11 physics.

If you want to know what to expect once Grade 11 starts, our post on why Grade 11 physics feels so hard explains the jump.

When a physics tutor helps in Grade 9 or 10

Most students handle these units without help. A tutor is worth it when the physics unit mark lags behind the others, or when the plan includes SPH3U and then SPH4U, which programs such as U of T Engineering require. Go2Grad's tutors are graduate students and graduates in physics, math and the sciences, including PhD candidates, who also tutor SPH3U and SPH4U. We have worked with 290+ students across 4,700+ lessons.

Grade 9 and 10 physics FAQ

Is there a physics course in Grade 9 or 10 in Ontario?

No. Physics is a unit inside Grade 9 Science (SNC1W), where it covers electricity, and Grade 10 Science (SNC2D), where it covers light and geometric optics. The first stand-alone physics course is SPH3U in Grade 11.

What do you learn in Grade 9 physics?

The SNC1W electricity strand: static and current electricity, conductors, DC circuit components, the relationship between current, potential difference and resistance, series and parallel circuits, and the efficiency of electrical devices.

Is Grade 10 physics hard?

The optics unit is very manageable with careful ray diagrams. Most lost marks come from rushed diagrams and incomplete image descriptions rather than difficult math.

Do I need SNC2D to take SPH3U?

Yes. SPH3U lists Science, Grade 10, Academic (SNC2D) as its prerequisite.

If Grade 9 circuits or Grade 10 optics left gaps, or you want SPH3U to start on solid ground, request a tutor. We follow up with a free consultation to find the exact gap, then match you with a physics tutor within 2 to 3 days. Tutoring starts at $47.50/hour on a 20-hour package; see our pricing page for details.

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