Title: Scale model of the moon, earth, and sun
… and many graphics that help us learn about the moon.Principle(s) Investigated: Making a scale model of a portion of our solar system (the moon, earth, and sun).In the full 1.5 hours (including 2 short movies and a PowerPoint presentation), we looked into:
How our moon compares to other moons in our solar system in size and color.
Why the moon has phases. Why we don't have an eclipse every month.
Why we have high and low tides.
6 moon rocks borrowed from NASA. We also look at moon rock and moon dust simulants.
A comparison of an Apple iPhone 5s and the Apollo Guidance Computer.
What the far side of the moon looks like.
The central focus of this 1.5 hour lesson is for the students to learn about our moon, and try to comprehend the scale of our solar system. An acrylic disc containing real moon rocks was borrowed from NASA for the lesson. For the first 30 minutes of this lesson I give a presentation about the moon while the students took turns looking at moon rocks as they were passed from student to student. Also borrowed from NASA and passed around the class were moon dust simulant and rocks that are similar to moon rocks. During the presentation students were encouraged to ask questions.
NGSS Cross Cutting Concepts
1. Patterns. Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.
phases of the moon
tides
days last 24 hours
lunar month is 29.53 days
2. Cause and effect: Mechanism and explanation. Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.
Tides are effected by the position of the moon, and to a lesser extent the position of the sun.
Phases of the moon are a result of the location of the moon relative to the sun and earth.
3. Scale, proportion, and quantity. In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale, proportion, or quantity affect a system’s structure or performance.
Given a globe, make a scale model of a portion of our solar system (the moon, earth, and sun).
To better understand the scale, also scale down the speed of sound and speed of light.
4. Systems and system models. Defining the system under study — specifying its boundaries and making explicit a model of that system — provides tools for understanding and testing ideas that are applicable throughout science and engineering.
Given a globe, make a scale model of a portion of our solar system (the moon, earth, and sun).
To better understand the scale, also scale down the speed of sound and speed of light
6. Structure and function. The way in which an object or living thing is shaped and its substructure determine many of its properties and functions.
How the moon formed (likely from the earth being struck by a giant impact).
How craters on the moon were formed.
We also examine simulated moon dust and actual moon rocks.
7. Stability and change. For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.
The moon is tidally locked to the earth.
Materials:
Globes
string
meter stick
calculator
Procedure: Given a globe, we want to make a model of the sun, earth, and moon system at the correct scale in size and distance.
Students are given the following diameters and distances:
Sun diameter = 1.39 x 109 m
Average distance from the sun to the earth = 1.49 x 1011 m
Earth diameter = 1.27 x 107 m
Average distance from the earth to the moon = 3.84 x 108 m
Moon diameter = 3.48 x 106 m
Students measure a globe with a string and meter stick.
Students get out a sheet of paper.
Worksheet on page 19 of 39 page PowerPoint presentation. Text in black should be copied.
Students figure out what to write to replace the orange text. Text in orange should not be copied.
Student prior knowledge:
Scientific notation (a × 10b)
basic algebra: the student should be able to multiply or divide both sides of an equation by the same variable.
Explanation:
Students measure our globe.
Students calculate the scale for our model:
Students calculate the size of our model moon: 48mm
This is as much as I expect my 8th grade students to do in class.
The most advanced students can do additional calculations, or help fellow students with their calculations.
I present the students with the rest of the results:
We discuss our results.
I show the students where the sun could be placed using mapping software (google maps):
Questions & Answers:
1. What is scale?
Wikipedia: In Euclidean geometry, uniform scaling (or isotropic scaling) is a linear transformation that enlarges (increases) or shrinks (diminishes) objects by a scale factor that is the same in all directions. The result of uniform scaling is similar (in the geometric sense) to the original.
Uniform scaling is common when making models for toys:
2. Why do we make scale models?
We make some models in order to better understand a system. Our model of the sun, earth, and moon are a good example of this.
In order to save money, scale models are often built to test potential aircraft designs in a wind tunnel.
This is a 1:11 3D printed model:
3. How does our moon compare to other moons in our solar system?
Our moon is not the largest moon in our solar system.
The Moon is exceptionally large relative to Earth: a quarter the diameter of the planet and 1/81 its mass. It is the largest moon in the Solar System relative to the size of its planet, though Charon is larger relative to the dwarf planet Pluto, at 1/9 Pluto's mass. Notice Venus and Mercury are not included in this picture – they are the only planets that do not have moons.
Applications to Everyday Life:
We often think of the moon as something we see at night. Some students are surprised to hear that half of the time that the moon is in the sky, it is during the day. The new moon is up during the day. It is not easy to see, because the sun is bright. This is a great picture for us to understand why this is true. It also helps us understand the phases of the moon. But it might throw off your understanding of the distances between the sun, earth, and moon.
Looking at the above picture you might think that the new moon should cause a solar eclipse each night. We don't have a solar eclipse every month, because the moon does not revolve around the earth on the same plane that the earth revolves around the sun.
Some student's want to know what the far side of the moon looks like.
Notice how this image is not perfectly “sewn together” by NASA.
Videos: