Grade 9 · Science

Grade 9 science

Grade 9 science is the first high-school course: chemistry gets numbers (protons, neutrons, electrons), electricity gets formulas, and ecology looks at whole systems. Here is what the year covers, where students usually get stuck, and one way to help.

What your teen learns this year

Courses differ by province and state, but most grade 9 science covers several of these:

Atoms and elements. Protons, neutrons and electrons, the periodic table, and how atoms form compounds.
Electricity. Current, voltage and resistance, circuits, and the cost of the energy we use.
Ecosystems and sustainability. How matter and energy move through ecosystems, and human effects such as climate change.
Space. The solar system and the universe, and how we explore them.
Scientific skills. Investigations, graphs and units, and in Ontario, links to technology and careers.

Ontario's grade 9 science is one course for everyone (SNC1W). In the US, grade 9 is often biology or physical science.

Where kids usually get stuck

1Reading the mass number as the neutron count. The mass number counts protons and neutrons together. The neutrons are what is left after taking away the protons.
2Forgetting that an ion has a different number of electrons. A sodium ion, Na⁺, has 11 protons but only 10 electrons: it lost one.
3Mixing up power and energy. A 100 W bulb uses 100 joules every second. The bill counts energy: power × time, in kilowatt-hours.

One of Pip's tricks

Neutrons are the gap

Use it when finding the protons, neutrons and electrons in an atom, or reading an isotope name like carbon-14.

The atomic number is the number of protons, and a neutral atom has the same number of electrons.
The mass number counts protons plus neutrons, so the neutrons are the gap: mass number minus atomic number.
An isotope name like carbon-14 gives you the mass number; look up the atomic number on the periodic table and subtract.

Watch it work. Carbon-13, atomic number 6. Protons = 6, and a neutral atom has 6 electrons too. Neutrons are the gap: 13 − 6 = 7. So: 6 protons, 7 neutrons, 6 electrons.

Why it works: protons and neutrons both sit in the nucleus and each counts as one unit of mass number, while electrons weigh almost nothing, so taking away the protons leaves exactly the neutrons.

Try three

Have a go, then tap to see the answer.

1.Oxygen-18 (atomic number 8): how many neutrons?
Show the answer
10. 18 − 8 = 10.
2.Sodium-23 (atomic number 11): how many electrons in a neutral atom?
Show the answer
11. A neutral atom has as many electrons as protons, and the atomic number is the proton count.
3.How many electrons does a sodium ion, Na⁺, have? (Sodium's atomic number is 11.)
Show the answer
10. The + means it has lost one electron: 11 − 1 = 10.

How Sparkpip fits in

Pip, Sparkpip's tutor, works through questions like these with your teen one small step at a time, using methods like the one above.

Start free See how it works

Your curriculum

Sparkpip is built on the grade 9 science curriculum for your province or state. The official pages:

Also: Grade 8 science · Grade 10 science · Grade 9 math · Grade 9 English