Analyze models of the Earth

Analyze the Models of the Earth

By Razelina Monguez

​Review

​Our solar system is made up of the Sun and all the objects that move around it. These objects include planets, moons, asteroids, and comets. The sizes of the objects in the solar system are difficult to imagine without the help of a model. Models make certain characteristics of a system easier to understand. A model can be a physical object, a graph, a diagram, or a simulation. The diagram is a model that shows the relative sizes of the Sun, the Moon, and Earth. The two small dots represent the accurate sizes of Earth and the Moon compared to the Sun. A close-up view of Earth and the Moon is also shown.

Multiple Choice

Complete the sentence to estimate the diameter of the Sun compared to Earth.

The Sun's diameter is about _________ times greater than Earth's.

• 3

• 10

• 100

​The Sun is the largest object in the solar system. While the Sun's diameter is about one hundred times greater than Earth's, the Sun's volume is more than one million times greater than Earth's. This means that over one million Earths could fit inside the Sun!

Multiple Select

If a model showed every object in the solar system, the model would be hard to understand. Scientists often choose to show certain characteristics in a model and leave out others. A characteristic that is left out is called a limitation of the model.

Look again at the model where the size of the Sun compared to Earth and the Moon is accurately represented. Then, answer the question below.

Which of the following are limitations of this model? Select all that apply.

• The model does not show the distances between Earth, the Moon, and the Sun.

• The model does not show the movement of Earth and the Moon around the Sun.

• The model does not show the size of Earth compared to the Sun and the Moon.

​The passage below describes two friends creating a physical model of the solar system. Read the passage and then answer the questions below.

​​​Ashley and Tina are creating a model showing the distances between Earth, the Moon, and the Sun. They choose a blue ball to represent Earth, a gray ball to represent the Moon, and a yellow ball to represent the Sun.

Ashley and Tina take the balls to the middle of a large field at their school. They know that Earth is about 240 thousand miles from the Moon and about 93 million miles from the Sun. In their model, they choose to represent one million miles with one step.

Multiple Choice

The yellow ball is in the center of the field. Tina wants to represent the distance from the Earth to the Sun. So, she should hold the blue ball ___________ away from the yellow ball.

• 93 inches

• 93 steps

• 240 steps

Multiple Choice

Ashley wants to represent the distance between the Earth and the moon. So, she should hold the gray ball ________ away from the blue ball.

• 4 inches

• 4 steps

• 240 steps

​In addition to showing size and distance, models can show how objects in the solar system move and interact with one another. For example, the model below uses arrows to show movement. The arrows show the movement of Earth and the Moon around the Sun. The gray lines represent the paths of Earth and the Moon.

Multiple Choice

Earth moves in a repeating path around the Sun. The regular, repeating path of an object as it moves around another object is called an orbit. Most planets move in a nearly circular orbit around the Sun.

Complete the sentence.

The model shows that ________ orbits Earth, and ______ orbits ________.

• the Earth, the Moon, Saturn
• the Moon, Earth, the Sun
• Venus, the Earth, Jupiter
• the Sun, the Moon, Mars

Multiple Choice

The model shows that Earth orbits the Sun, and the Moon orbits Earth.

It takes one year for Earth to orbit the Sun once. During this time, the Moon orbits Earth about 12 times.

Complete the sentence,

It takes about ____ days for the Earth to orbit the Sun, and about _____ days for the Moon to orbit Earth.

• 300 days, 28 days
• 365 days, 30.4 days
• 365 days, 60 days
• 400 days, 15 days

​Earth is always in motion. In addition to orbiting the Sun, Earth is constantly rotating, or spinning. Earth rotates around an imaginary line called an axis.

​How does Earth's rotation affect what we see in the night sky? The North Star, also known as Polaris, has long been a trusted navigation tool for explorers. This is because Polaris does not appear to move over the course of the night. Instead, it remains in the northern part of the sky. Polaris is the star that Earth's axis points closest to. When Earth rotates, all the stars appear to move around Polaris while Polaris stays still. But really, it is Earth that is rotating!

Multiple Choice

The passage below describes a student creating a physical model of Earth's rotation.

Tony is creating a model showing how Earth rotates over the course of one day. He uses a globe to represent Earth.

Tony knows that Earth spins on its axis, completing one rotation every 24 hours. He slowly spins the globe counterclockwise, completing one rotation in about 6 seconds.

In Tony's model, 1 second of rotation represents about _____ hours.

• 2 hours
• 6 hours
• 12 hours
• 4 hours

Multiple Select

Look at the model showing the movement of Earth, the Moon, and the Sun. Like all models, it shows some characteristics and leaves out others.

What are the characteristics of the solar system?. Click all that apply.

• Earth's orbit the Sun

• The Sun's diameter is over 100 times larger than the Earth

• Earth is more than 350 times as far from the Sun as it is from the Moon

• The moon completes about 12 orbits around Earth each time earth orbits the Sun

• Earth rotates