🔬 9th grade Science: how to help at home

What each unit covers

1. 🧫Cells from Cells

   How cells copy their DNA and divide by mitosis, the stages in order, why cells divide for growth and healing, and what can go wrong when cell growth isn't controlled.

2. 🌱Reproduction

   How organisms reproduce with one parent or two, why sexual reproduction creates variety, the parts of a flower, and the strengths and weaknesses of each approach.

3. 🌿Photosynthesis & Respiration

   The reactants, products and location of photosynthesis and cellular respiration, why they are complementary, and how they link plants, animals and the carbon cycle.

4. 🧬Human Reproductive System

   Practices the structure and function of the human reproductive system and the role of hormones, in plain scientific terms. Families may wish to read it together.

5. 🦎Evolution & Selection

   Practices variation, adaptation, natural and artificial selection, mutations, the evidence for evolution from fossils and rock layers, and how new species can form.

6. ⚛️Atoms & Electrons

   Protons, neutrons and electrons, drawing electron shells for the first 20 elements, valence electrons, periodic table groups and periods, and ions and isotopes.

7. 🧪Electrons & Compounds

   How valence electrons decide whether atoms gain, lose or share electrons, ionic and covalent compounds, and reading simple chemical formulas.

8. ⚗️Chemical Change

   Telling a chemical change from a physical change, reading simple word and symbol equations, why mass is conserved, what speeds a reaction up, exothermic and endothermic changes, and GHS safety.

9. 🚀Forces, Motion & Momentum

   Practices Newton's second law (F = ma), momentum and its conservation, and designing devices that reduce the force of a collision.

10. 🧲Energy & Magnetism

    Practices the law of conservation of energy, potential and kinetic energy, efficiency, and the link between electric current and magnetic fields in electromagnets and generators.

11. 🔌Circuits & Ohm's Law

    Circuit components and their jobs, current, potential difference and resistance with their symbols and SI units, calculating with V = I × R, and how current, voltage and resistance behave in series and parallel circuits.

12. 🌎Science & Society

    Practices weighing the costs and benefits of technologies, spotting unforeseen consequences, taking action on science issues, and linking science to careers and hobbies.

13. 🌲Ecosystem Dynamics

    Practices carrying capacity, energy flow and the 10% rule, how ecosystems respond to disturbance, and evaluating solutions to human impacts, using New York's Adirondack lakes, Great Lakes and Hudson River as examples.

14. 🫀Body Systems & Homeostasis

    Practices the levels of organization in a multicellular organism (cells, tissues, organs and organ systems) and how systems work together, and how feedback loops such as sweating, shivering and insulin keep body temperature, water and blood sugar in a stable range.

15. 🧬DNA, Proteins & Traits

    Practices how the order of bases in DNA codes for the order of amino acids in proteins, how cells build carbon-based molecules from sugars and elements like nitrogen, how chromosomes carry genes from parents to offspring, and using Punnett squares and probability to predict how traits are spread in offspring and populations.

16. 🐺Populations & Evolution

    Practices using numbers to describe populations and biodiversity, judging the evidence that group behavior such as packs, schools and herds helps animals survive, using proportions to explain how a helpful inherited trait spreads, and how environmental change can grow some populations, form new species and end others.

17. 🌋Plate Tectonics

    Practices modeling Earth's interior from seismic evidence, how convection in the mantle moves plates, what happens at each kind of plate boundary, and why ocean crust is young while some continental rock, like the Adirondacks', is over a billion years old.

18. ☄️Earth's Early History

    Practices using evidence from meteorites, moon rocks and Earth's oldest minerals to describe how Earth formed about 4.6 billion years ago, and how living things and Earth's systems changed each other, from early microbes adding oxygen to the air to plants building soil.

19. 🌬️Air Masses & Fronts

    Practices how air masses get their temperature and humidity from where they form, what happens when they meet at cold, warm and stationary fronts, reading front symbols and air pressure, and explaining New York weather such as nor'easters and lake-effect snow.

20. ♻️Engineering for Sustainability

    Practices how engineers tackle big challenges such as clean water and pollution: setting criteria and constraints, breaking a problem into smaller parts, using models and computer simulations to test ideas and manage resources sustainably, and refining technologies that reduce human impacts on natural systems.

21. 🌗Moon, Tides & Seasons

    Practices explaining the repeating cycles of moon phases, eclipses, tides and seasons, and how gravity and Kepler's laws describe the orbits of the moon, planets and satellites.

22. ✨Stars & the Universe

    Practices how fusion in the sun's core makes the energy that reaches Earth, the life cycles of stars and the elements they make, and the evidence for the Big Bang: galaxies moving apart, leftover microwave radiation and the mix of elements.

23. 🌡️Climate & Earth's Systems

    Practices how energy flow and feedbacks among Earth's systems change climate, how carbon cycles through air, oceans, rocks and life, the evidence from ice cores and glaciers, and how people can reduce the causes of climate change.

24. 🏞️Water, Ice & Landscapes

    Practices how water's properties drive weathering, erosion and deposition, how glaciers shaped New York's valleys, lakes and Long Island, and how landforms, water and hazards shape where people live and work.

25. 🌈Waves & Electromagnetic Radiation

    Practices the wave equation (speed = frequency × wavelength), the electromagnetic spectrum and why higher-frequency radiation such as ultraviolet and X-rays can harm living tissue, evidence that light acts as both a wave and a particle, why digital transmission is reliable, and devices that use waves, from solar panels to fiber optics.

26. ⚗️Gases, Solutions, Acids & Bases

    Practices how the pressure, volume and temperature of a gas are related, how solutes dissolve and what affects solubility, comparing acids and bases with pH and neutralization, and reactions where electrons move from one substance to another (oxidation and reduction), as in rusting and batteries.

27. ⚛️Nuclear Energy & Bond Energy

    Practices how nuclei change in fission, fusion and radioactive decay, what alpha, beta and gamma radiation are, half-life calculations, and how the energy absorbed to break bonds and released to form bonds makes a reaction give off or take in energy.

28. 🧲Forces at a Distance & Heat Flow

    Practices reasoning with Newton's law of gravitation and Coulomb's law (how forces change when masses, charges or distances change), and how thermal energy flows from hotter to colder objects until they reach the same temperature, including simple mixing calculations.