Middle school · for use with the Next Generation Science Standards*

MS-ESS1-1: Moon phases, eclipses and seasons

What students must show for performance expectation MS-ESS1-1, with a lesson sequence built on live data, the misconceptions to expect, and assessment questions with answers.

FreeMost tools need no sign-upNo ads on this page
At a glance
5lesson steps
3live tools
5assessment questions
11 to 14age range

Last updated . Curriculum links last reviewed November 2026.

What students must show

Our summary
  • Students build and use a model of the Earth, Sun and Moon that explains why the Moon goes through phases, why solar and lunar eclipses happen, and why we have seasons.
In scope

Models can be physical, drawn or conceptual.

Not assessed

The official page sets no assessment boundary for this standard.

Our summary, in our own words. Read the official wording.

The three dimensions

Middle school
Practice

Developing and using models

Develop and use a model to describe phenomena.

Core idea

ESS1.A and ESS1.B

The apparent motions of the Sun, Moon and stars can be modeled; the solar-system model explains eclipses; Earth's tilted axis causes the seasons.

Crosscutting

Patterns

Patterns can be used to identify cause and effect.

Live tools for this standard

3 tools
Moon globetoday's phase, lit the way it is right nowEclipse trackerthe next solar and lunar eclipses, and what each will look like from your townLive ISS trackerthe edge of the night side shows which pole leans toward the Sun today

Lesson sequence

Engage to evaluate
  1. Engage10 min

    Show today's live Moon. Ask students to sketch what causes its shape. Collect the "Earth's shadow" idea without correcting it yet.

  2. Explore30 min

    In a dark room, each student holds a polystyrene ball at arm's length in front of a lamp and turns slowly. Record the phase at 8 positions and find the one that matches today's live Moon.

  3. Explain20 min

    Eclipses: line up the lamp, your head and the ball. Solar eclipse: the ball blocks the lamp. Lunar eclipse: the ball is in your head's shadow. Now tilt the ball's path about 5 degrees: why don't eclipses happen every month? Check the eclipse tracker for the next real ones.

  4. Elaborate20 min

    Seasons: tilt a globe 23.4 degrees and walk it around the lamp. In June the north leans toward the lamp. Compare with where daylight ends on the tracker today.

  5. Evaluate15 min

    Each student explains one phenomenon (a phase, an eclipse or a season) with a labeled diagram of their model.

Common misconceptions

3 to watch for
Students often think

The Moon's phases are caused by Earth's shadow.

In fact

Half of the Moon is always lit by the Sun; as it circles us we see more or less of that lit half. Earth's shadow only reaches the Moon during a lunar eclipse.

Try this

The ball model shows every phase without your head ever shading it.

Students often think

It is summer when Earth is closest to the Sun.

In fact

Earth is closest to the Sun in early January, during the northern winter. The tilt changes how directly sunlight strikes and how long the days last.

Try this

Point a flashlight at the desk from directly above, then tilt it: the tilted patch spreads out and looks dimmer.

Students often think

There is an eclipse every month.

In fact

The Moon's orbit is tilted about 5 degrees, so most months it passes above or below the Sun or Earth's shadow.

Try this

The tilted path in the model; the eclipse tracker shows 4 to 7 eclipses a year.

Assessment questions

Answers folded away

MS-ESS1-1: Moon phases, eclipses and seasons · orbitalradar.com/schools/us/standards/ms-ess1-1

  1. Which phase is the Moon in during a solar eclipse?
    1. New Moon
    2. Full Moon
    3. First quarter
  2. Why is it summer in the Northern Hemisphere in June?
    1. Earth is closest to the Sun
    2. The north is tilted toward the Sun
    3. The Sun gives off more energy
  3. A lunar eclipse can only happen at full Moon. Use your model to explain why.
  4. Why is it winter in Australia when it is summer in the US?
  5. Look at today's live Moon. Is it waxing or waning? When is the next full Moon?
Answer key
  1. New Moon.
  2. The north is tilted toward the Sun.
  3. Only at full Moon is the Moon on the far side of Earth from the Sun, where Earth's shadow points.
  4. When the north tilts toward the Sun, the south tilts away from it.
  5. It depends on the date: check the Moon globe.

Worksheet

US Letter
Moon diary

One page on US Letter, filled in with live numbers when you open it. Teacher notes and answers included.

The same idea in state standards

Texas, Florida, Georgia

Related, not equivalent: each state words and groups its standards differently.

More standards pages

Middle school

Grade 1: 1-ESS1-1 1-ESS1-2

Grade 5: 5-PS2-1 5-ESS1-1 5-ESS1-2

Middle school: MS-ESS1-1 MS-ESS1-2 MS-ESS1-3 MS-PS2-4

High school: HS-ESS1-1 HS-ESS1-2 HS-ESS1-3 HS-ESS1-4 HS-ESS1-6 HS-PS2-4

Middle school activities All 15 standards

About these codes

These are our suggestions for where each tool fits. Always preview a page before using it with a class: some tools show ads, these school pages do not.

Codes are performance expectations of the Next Generation Science Standards*, for example 5-ESS1-2. Each summary is our own wording; follow the link on a standard page for the official text.

Suggest a link

Know a better fit for your class, or a topic we have missed? Tell us and we will add it.

Share this page with one link: orbitalradar.com/schools/us/standards/ms-ess1-1

Cite this page

Pick a style, then copy it or download it for your reference manager.

Orbital Radar. (2026, November 6). MS-ESS1-1: Moon phases, eclipses and seasons. Retrieved November 6, 2026, from https://orbitalradar.com/schools/us/standards/ms-ess1-1

“MS-ESS1-1: Moon phases, eclipses and seasons.” Orbital Radar, 6 Nov. 2026, orbitalradar.com/schools/us/standards/ms-ess1-1. Accessed 6 Nov. 2026.

Orbital Radar (2026) MS-ESS1-1: Moon phases, eclipses and seasons. Available at: https://orbitalradar.com/schools/us/standards/ms-ess1-1 (Accessed: 6 November 2026).

Orbital Radar. “MS-ESS1-1: Moon phases, eclipses and seasons.” Last modified November 6, 2026. https://orbitalradar.com/schools/us/standards/ms-ess1-1.

@misc{orbitalradar_schools_us_standards_ms_ess1_1,
  author       = {{Orbital Radar}},
  title        = {MS-ESS1-1: Moon phases, eclipses and seasons},
  year         = {2026},
  month        = nov,
  howpublished = {\url{https://orbitalradar.com/schools/us/standards/ms-ess1-1}},
  url          = {https://orbitalradar.com/schools/us/standards/ms-ess1-1},
  urldate      = {2026-11-06},
  note         = {Accessed 2026-11-06}
}
TY  - ELEC
AU  - Orbital Radar,
TI  - MS-ESS1-1: Moon phases, eclipses and seasons
PY  - 2026
DA  - 2026/11/06
PB  - Orbital Radar
UR  - https://orbitalradar.com/schools/us/standards/ms-ess1-1
Y2  - 2026/11/06
LA  - en-US
ER  -
Download RISFor Zotero, EndNote and Mendeley

Live figures change, so keep the date you accessed the page. How to cite Orbital Radar

* Next Generation Science Standards is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.