Earth and Space Science
Earth and Space Science on the Grade 5 OST examines Earth's cycles and its place in the solar system. Questions ask you to use models, diagrams, and data to explain what drives water movement, weathering, day and night, shadows, moon phases, and seasons.
Core rules and concepts
- The Sun is the major source of energy for the water cycle. Evaporation changes liquid water to vapor; condensation changes vapor to droplets; precipitation returns water to Earth; runoff and infiltration move it downhill and underground.
- Water is conserved in a closed system: it changes state and location, but no new water is created.
- Weather is the short-term state of the atmosphere; climate is the long-term pattern.
- Earth rotates on its axis once about every 24 hours, causing day and night and the apparent movement of the Sun. Shadows are shortest near noon and longest near sunrise and sunset.
- Earth revolves around the Sun once a year. The tilt of Earth's axis, not distance from the Sun, causes seasons.
- The Moon's phases result from the changing angle between Earth, the Moon, and the Sun; the Moon does not make its own light.
Worked example
A sidewalk puddle is gone after a sunny afternoon. Explain the change. Reasoning: energy from the Sun increases evaporation, turning liquid water into water vapor that mixes with air. The water is not destroyed; it moved into the atmosphere and may condense later. If a cold glass is nearby, droplets form because vapor loses energy and condenses.
Traps that cost marks
- Saying heat destroys water or that water disappears.
- Confusing weather and climate.
- Claiming seasons happen because Earth is closer to the Sun.
- Treating moon phases as Earth's shadow; that explains eclipses, not phases.