SC15.6.1

Science (2015) Grade(s): 6

SC15.6.1
Create and manipulate models (e.g., physical, graphical, conceptual) to explain the occurrences of day/night cycles, length of year, seasons, tides, eclipses, and lunar phases based on patterns of the observed motions of celestial bodies.

Unpacked Content

Scientific and Engineering Practices

Developing and Using Models

Crosscutting Concepts

Patterns

Knowledge

Students know:

Earth rotates on its tilted axis once in approximately 24 hours; this rotation is considered an Earth day. Due to the rotation of the Earth, the side of the Earth facing the sun experiences light (day); the side of the Earth facing away from the sun experiences dark (night).
The Earth-moon system revolves around the sun once in approximately 365 days; this revolution is considered an Earth year.
The distance between Earth and the sun stays relatively constant throughout the Earth's orbit.
The Earth's rotation axis is tilted with respect to its orbital plane around the sun. Earth maintains the same relative orientation in space, with its North Pole pointed toward the North Star throughout its orbit.
Solar energy travels in a straight line from the sun and hits different parts of the curved Earth at different angles — more directly at the equator and less directly at the poles.
Because the Earth's axis is tilted, the most direct and intense solar energy occurs over the summer months, and the least direct and intense solar energy occurs over the winter months.
The change in season at a given place on Earth is directly related to the orientation of the tilted Earth and the position of Earth in its orbit around the sun because of the change in the directness and intensity of the solar energy at that place over the course of the year.
Summer occurs in the Northern Hemisphere at times in the Earth's orbit when the northern axis of Earth is tilted toward the sun.
Summer occurs in the Southern Hemisphere at times in the Earth's orbit when the southern axis of Earth is tilted toward the sun.
Winter occurs in the Northern Hemisphere at times in the Earth's orbit when the northern axis of Earth is tilted away from the sun.
Winter occurs in the Southern Hemisphere at times in the Earth's orbit when the southern axis of Earth is tilted away from the sun.
A tide is the daily rise and fall of sea level.
Low tide is the lowest sea level at a particular time and place on Earth.
High tide is the highest sea level at a particular time and place on Earth.
Tides occur as a result of the moon's gravitational pull on the Earth.
Solar energy is prevented from reaching the Earth during a solar eclipse because the moon is located between the sun and Earth.
Solar energy is prevented from reaching the moon (and thus reflecting off of the moon to Earth) during a lunar eclipse because Earth is located between the sun and moon.
Because the moon's orbital plane is tilted with respect to the plane of the Earth's orbit around the sun, for a majority of time during an Earth month, the moon is not in a position to block solar energy from reaching Earth, and Earth is not in a position to block solar energy from reaching the moon.
A lunar eclipse can only occur during a full moon.
The moon rotates on its axis approximately once a month.
The moon orbits Earth approximately once a month.
The moon rotates on its axis at the same rate at which it orbits Earth so that the side of the moon that faces Earth remains the same as it orbits.
The moon's orbital plane is tilted with respect to the plane of the Earth's orbit around the sun.
Solar energy coming from the sun bounces off of the moon and is viewed on Earth as the bright part of the moon.
The visible proportion of the illuminated part of the moon (as viewed from Earth) changes over the course of a month as the location of the moon relative to Earth and the sun changes. This change in illumination is known as the lunar phase.
The moon appears to become more fully illuminated until "full" and then less fully illuminated until dark, or "new," in a pattern of change that corresponds to what proportion of the illuminated part of the moon is visible from Earth.
The lunar phase of the moon is a result of the relative positions of the Earth, sun, and moon.

Skills

Students are able to:

Develop a model of the Sun-Earth-Moon systems and identify the relevant components.
Describe the relationships between components of the model.
Use patterns observed from their model to provide causal accounts for events and make predictions for events by constructing explanations.

Understanding

Students understand that:

Patterns in the occurrences of day/night cycles, length of year, seasons, tides, eclipses, and lunar phases can be observed and explained using models based on observed motion of celestial bodies.

Vocabulary

Model
Earth
Moon
Sun
Orbit
Rotation
Axis
Tilted
Day
Night
Hour
Revolution
Constant
Orbital plane
Orientation
Solar Energy
Equator
Poles
Northern Hemisphere
Southern Hemisphere
Winter
Summer
Tides
Gravitational pull
Low tide
High tide
Eclipse
Solar eclipse
Lunar Eclipse
Lunar phases (new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent)
Illumination