Lunar Phases

ASPIRE - Astrophysics Science Project Integrating Research and Education
Type Category
Instructional Materials
Interactive Simulation , Simulation
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



Lunar Phases is an interactive simulation consisting of three scaffolding activities. In Activity One, students are tasked with determining which half of the Earth and Moon is lit as the Moon revolves around the Earth. The directions state that users should click on the picture to start the simulation; however, no such illustration exists. Rather, users should click on the box labeled "Activity One" in order to begin. If students select the correct shadows on their first attempt, a congratulatory message will appear. If this message fails to appear, then students should click the right arrow. They will then receive an error message and must reassess their work. In Activity 2, students are asked to select the illustration that matches how the Moon appears to us as it revolves around Earth. If wrong answers are selected, students will not be allowed to go on to the next phase. Students receive immediate feedback if correct answers are selected. After working through the phases, students can then take a short assessment to check their understanding. In Activity 3, students run a simulation which ties together the information obtained in the first two activities. Two viewpoints are provided here: students can view the Sun-Earth-Moon system from a point in space as well as view the lunar phases from Earth. Teachers should note that students are not active participants in Activity Three. Lunar Phases requires both JavaScript and Adobe Flash Player.

Intended Audience

- none -
Educational Level
  • Middle School
  • Grade 8
  • Grade 7
  • Grade 6
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-ESS1-1 Develop and use a model of the Earth-sun-moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons.

Clarification Statement: Examples of models can be physical, graphical, or conceptual.

Assessment Boundary: none

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
In this simulation, students use an interactive model to investigate the cyclic patterns of lunar phases. Since MS-ESS1-1 includes model development, students would need to design their own model to meet the Performance Expectation. To achieve this, teachers may want to provide styrofoam balls and flashlights to their students and encourage them to create a kinesthetic model that mimics the on-line simulation. This site does not deal with eclipses or seasons.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Lunar Phases is an interactive simulation that allows students to study the cyclic nature of the Moon's rotation around Earth. Please note, that in these activities, students are not developing their own model. In order to fulfill the requirements of the Practice, students will need to create their own model which can then be used to explain phases. As mentioned above, teachers could provide students with styrofoam balls and flashlights and then challenge their students with developing just such a model.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
Activities 1 and 2 of Lunar Phases require students to align shadows and determine the appearance of the Moon at selected locations in its orbit around the Earth. This should lead students to the dual conclusions that the Moon is always half illuminated by the Sun and that the cyclic nature of lunar phases is due to the Moon’s location relative to Earth. Unfortunately, Activity 3, which uses these conclusions as the basis for a simulation, does not allow for user input. To ensure that students do not become passive observers, teachers should construct questions that can be answered by the simulation. For example, students may be tasked with discussing why the New Moon is not visible to observers on Earth or why different halves of the Moon are illuminated for the First and Third Quarters.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
The simulation found in Activity 3 does not allow students to enter data or change variables. Therefore, once students appear to understand that lunar phases are a result of a cyclic change in the Moon’s position relative to Earth, teachers may want to administer a pen and paper summative assessment using various geometric alignments of the Sun-Earth-Moon. Students would then be required to use their knowledge of the patterns gained in the activities to predict lunar phases.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The sequential nature of the three activities in Lunar Phases strongly aligns to the portion of the Disciplinary Core Idea pertaining to the Moon’s motion. Throughout the simulation, the practice of using models to describe phenomena is reinforced while the relationship between lunar phases and location in the cyclic orbit (patterns) is emphasized. The primary drawback of this simulation is that students are using, not creating, a model for phases.

  • Instructional Supports: Lunar Phases provides students with an opportunity to use a scientifically accurate representation of the Sun-Earth-Moon system in order to explain the appearance of phases. The simulation uses grade appropriate language; however, limited information/explanation is provided. Teachers will need to produce writing prompts in order to assist students in constructing their explanations for the appearance of phases. No suggestions are provided to assist the teacher in differentiating the lesson.

  • Monitoring Student Progress: Lunar Phases does not include either a formative assessment or scoring guidelines to assess student achievement. A 9-question assessment is provided at the end of Activity 2; however, students only receive feedback on Questions 1-8.

  • Quality of Technological Interactivity: Activities 1 and 2 require student input and provide instantaneous feedback. A short assessment follows Activity 2 which serves to monitor understanding. Because students are not allowed to input data in Activity 3, there is a chance that they may become confused or lose focus. Teachers should be prepared to re-direct student attention with questions/scenarios for students to solve. An example of this could include a task dealing with the when and why of specific lunar phase occurrence. As indicated in the introduction, the directions for accessing the activities are confusing.