OST Grade 5 Science cheat sheet

Earth's rotation on its axis (about 24 hours) causes day and night; rotation goes west to east, so the Sun appears to rise in the east and set in the west.

Earth's revolution around the Sun (about 365.25 days) plus the 23.5° tilt of its axis causes the seasons; the hemisphere tilted toward the Sun gets more direct sunlight and longer days.

Moon phases repeat in about 29.5 days: new → waxing crescent → first quarter → waxing gibbous → full → waning gibbous → third quarter → waning crescent.

The Moon's gravity causes ocean tides; most coasts have two high tides and two low tides roughly every 24 hours 50 minutes.

A solar eclipse happens at new moon when the Moon blocks the Sun; a lunar eclipse happens at full moon when Earth's shadow falls on the Moon.

The Sun is a medium-sized star made mostly of hydrogen and helium; it gives Earth light and heat and is the center of our solar system.

Rock layers follow superposition: in undisturbed layers, the oldest rock is at the bottom and the youngest is at the top; fossils in layers show relative age.

Weathering breaks rock into smaller pieces, erosion moves the pieces (water, wind, ice, gravity), and deposition drops them, building deltas and dunes.

A food chain always starts with a producer (plant or algae) that makes its own food by photosynthesis; arrows point in the direction energy flows, toward the eater.

Roles in an ecosystem: producers make food, consumers eat other organisms (herbivore, carnivore, omnivore), and decomposers (fungi, bacteria) break down dead material and return nutrients to soil.

Photosynthesis uses carbon dioxide + water + sunlight to make sugar and release oxygen; respiration uses sugar + oxygen to release energy, carbon dioxide, and water.

Adaptations are inherited traits that help an organism survive in its habitat: camouflage, thick fur, long roots, sharp beaks, migration, and hibernation.

An inherited trait comes from parents through genes (eye color, fur pattern); a learned behavior is acquired from experience (riding a bike, a bird learning a song).

In a population, individuals with helpful variations are more likely to survive and reproduce, so those traits become more common over generations (natural selection).

Symbiosis types: mutualism benefits both organisms, commensalism helps one and does not affect the other, and parasitism helps one and harms the other.

Cells are the basic unit of life; the cell membrane controls what enters and leaves, the nucleus holds genetic information, and chloroplasts in plant cells carry out photosynthesis.

Matter is anything with mass and volume; the three common states are solid (fixed shape), liquid (fixed volume, changing shape), and gas (fills its container).

Physical changes alter form but not identity (melting, dissolving, cutting); chemical changes form new substances and often show color change, gas, heat, light, or a new odor.

Density = mass ÷ volume; an object floats in a fluid if its density is less than the fluid's density and sinks if its density is greater.

Mixtures can be separated by physical means (filtering, evaporating, magnets, sorting); compounds must be broken apart by chemical reactions.

Newton's laws: an object at rest stays at rest unless a force acts; force = mass × acceleration; every action has an equal and opposite reaction.

Forces have size and direction; balanced forces cause no change in motion, while unbalanced forces change an object's speed or direction.

Energy forms include motion, light, sound, heat, electrical, and stored (potential) energy; energy is never created or destroyed, only transferred or transformed.

In a simple circuit, current flows only through a closed loop; a series circuit has one path (one bulb out = all out) and a parallel circuit has branches (one bulb out = others stay lit).

A testable question names one variable to change and one to measure; 'Does fertilizer amount affect plant height?' is testable, while 'Are plants nice?' is not.

Variables: the independent variable is what the experimenter changes on purpose, the dependent variable is what is measured, and controlled variables are kept the same.

A fair test changes only one variable at a time; a control group gets no treatment and is used for comparison.

A hypothesis is a prediction that can be tested; it is supported or not supported by data, never 'proven' by one experiment.

An observation uses the senses or measurements; an inference is a conclusion based on evidence (footprints in mud → an animal walked there).

Tools: metric ruler for length, graduated cylinder for liquid volume, balance for mass, thermometer for temperature, hand lens or microscope for small detail.

Data are most clearly shown with graphs: bar graphs compare categories, line graphs show change over time, and circle graphs show parts of a whole.

A valid conclusion restates the question, uses the data as evidence, and names sources of error; repeating trials improves reliability.

Earth's rotation on its axis (about 24 hours) causes day and night; rotation goes west to east, so the Sun appears to rise in the east and set in the west.

Earth's revolution around the Sun (about 365.25 days) plus the 23.5° tilt of its axis causes the seasons; the hemisphere tilted toward the Sun gets more direct sunlight and longer days.

Moon phases repeat in about 29.5 days: new → waxing crescent → first quarter → waxing gibbous → full → waning gibbous → third quarter → waning crescent.

The Moon's gravity causes ocean tides; most coasts have two high tides and two low tides roughly every 24 hours 50 minutes.

A solar eclipse happens at new moon when the Moon blocks the Sun; a lunar eclipse happens at full moon when Earth's shadow falls on the Moon.

The Sun is a medium-sized star made mostly of hydrogen and helium; it gives Earth light and heat and is the center of our solar system.

Rock layers follow superposition: in undisturbed layers, the oldest rock is at the bottom and the youngest is at the top; fossils in layers show relative age.

Weathering breaks rock into smaller pieces, erosion moves the pieces (water, wind, ice, gravity), and deposition drops them, building deltas and dunes.

A food chain always starts with a producer (plant or algae) that makes its own food by photosynthesis; arrows point in the direction energy flows, toward the eater.

Roles in an ecosystem: producers make food, consumers eat other organisms (herbivore, carnivore, omnivore), and decomposers (fungi, bacteria) break down dead material and return nutrients to soil.

Photosynthesis uses carbon dioxide + water + sunlight to make sugar and release oxygen; respiration uses sugar + oxygen to release energy, carbon dioxide, and water.

Adaptations are inherited traits that help an organism survive in its habitat: camouflage, thick fur, long roots, sharp beaks, migration, and hibernation.

An inherited trait comes from parents through genes (eye color, fur pattern); a learned behavior is acquired from experience (riding a bike, a bird learning a song).

In a population, individuals with helpful variations are more likely to survive and reproduce, so those traits become more common over generations (natural selection).

Symbiosis types: mutualism benefits both organisms, commensalism helps one and does not affect the other, and parasitism helps one and harms the other.

Cells are the basic unit of life; the cell membrane controls what enters and leaves, the nucleus holds genetic information, and chloroplasts in plant cells carry out photosynthesis.

Matter is anything with mass and volume; the three common states are solid (fixed shape), liquid (fixed volume, changing shape), and gas (fills its container).

Physical changes alter form but not identity (melting, dissolving, cutting); chemical changes form new substances and often show color change, gas, heat, light, or a new odor.

Density = mass ÷ volume; an object floats in a fluid if its density is less than the fluid's density and sinks if its density is greater.

Mixtures can be separated by physical means (filtering, evaporating, magnets, sorting); compounds must be broken apart by chemical reactions.

Newton's laws: an object at rest stays at rest unless a force acts; force = mass × acceleration; every action has an equal and opposite reaction.

Forces have size and direction; balanced forces cause no change in motion, while unbalanced forces change an object's speed or direction.

Energy forms include motion, light, sound, heat, electrical, and stored (potential) energy; energy is never created or destroyed, only transferred or transformed.

In a simple circuit, current flows only through a closed loop; a series circuit has one path (one bulb out = all out) and a parallel circuit has branches (one bulb out = others stay lit).

A testable question names one variable to change and one to measure; 'Does fertilizer amount affect plant height?' is testable, while 'Are plants nice?' is not.

Variables: the independent variable is what the experimenter changes on purpose, the dependent variable is what is measured, and controlled variables are kept the same.

A fair test changes only one variable at a time; a control group gets no treatment and is used for comparison.

A hypothesis is a prediction that can be tested; it is supported or not supported by data, never 'proven' by one experiment.

An observation uses the senses or measurements; an inference is a conclusion based on evidence (footprints in mud → an animal walked there).

Tools: metric ruler for length, graduated cylinder for liquid volume, balance for mass, thermometer for temperature, hand lens or microscope for small detail.

Data are most clearly shown with graphs: bar graphs compare categories, line graphs show change over time, and circle graphs show parts of a whole.

A valid conclusion restates the question, uses the data as evidence, and names sources of error; repeating trials improves reliability.