1) The document outlines a two-phase plan to create a scale model of the solar system using one of the classroom walls. 2) Phase I involves calculating the scale distances between the sun and each planet based on the wall length and the actual maximum distance between objects in the solar system. 3) Phase II will use a different scale to represent the actual sizes of each planet and the sun based on converting their real radii to radii that can be modeled on the classroom wall.

1. THE SOLAR SYSTEM
A scale model. The scale
Fran J. García Gil
Our objective: To make a scale model of the solar system using one of the wall of our
class. In order to work in this way, we have to work in two phases:
PHASE I: Calculate distances between the sun and the planets (orbit radius)
PHASE II: Represent a scale model of sun and the planets (the scale we will use here will be
different).
PHASE I: Distances between sun and the planets.
We have a wall of 8.9 m in the class, and the largest distance we want to represent is
30.06 AU (Astronomical Units).
Question 1: How many meters do we need to represent one AU
8.9m÷30.06 AU =0.30m every AU
Question 2: Investigate (Internet) the distance from the sun to the rest of the planets.
Question 3: Try to complete the following table:
Planet Real distance (AU) Class distance
Mercury 0.39
Venus 0.72
Earth 1
Mars 1,52
Jupiter 5,2
Saturn 9,54
Uranus 19,22
Neptune 30,06
PHASE II: Planet sizes
If we used the same scale we used for the distances between planets, we had a radium
for sun of 0.00459 AU. So, it will be better for us to chose another scale.
For example, Sun Radius could be 1.25 m. The problem now is, what will be the radius of
every planet?
Let's think. Sun real radius is 695,000 km. So, if we are going to make a sun wtih a radius of
1.25 m = 125 cm, every km is transformed into:
Question 1: How many real km are in 1 cm of the representation?
695,000km÷125cm=5560 km/cm

2. Question 2: How many cm do we need to represent a real km
125cm/695,000km=0.000180cm/ km
Question 3: Investigate (Internet) the radius of every planet.
Question 4: Try to complete the following table:
Planet Real diameter (km) Real radius (km) Class radius (cm)
Sun 695
Mercury 4878
Venus 12104
Earth 12576
Mars 6787
Jupiter 142800
Saturn 120000
Uranus 51118
Neptune 49528
To be continued... with the mathematical use of scales