A SOLAR SYSTEM SCALE MODEL
The amount of empty space in the Solar System is incredibly impressive, and
easy to demonstrate with a scale model. Younger kids obviously can’t calculate
how big everything should be, but they can be told that “the width of the Earth is
ten times smaller than Jupiter’s width” and be given a range of possible scale
objects to pick for an Earth model.
For our scale model, we picked a scale of 5,600 million – if you shrink everything
by 5,600 million, the Sun will be 25cm diameter – the size of a soccer ball.
We have rounded the actual distance measurements.
Actual Size
(diameter)
Sun
Mercury
Venus
Earth
[Moon
1,400,000 km
4,900 km
12,100 km
12,800 km
3,500 km
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
6,800 km
143,000 km
121,000 km
51,000 km
50,000 km
2,400 km
Actual Distance
from Sun
Scale Size
(diameter)
58 million km
108 million km
150 million km
380,000 km
from Earth
228 million km
778 million km
1,430 million km
2,900 million km
4,500 million km
5,900 million km
25 cm
1 mm
2 mm
2 mm
0.6 mm
1 mm
2.6 cm
2.2 cm
9 mm
9 mm
0.4 mm
Scale
Distance
from Sun
10 m
19 m
27 m
7 cm
from Earth]
40 m
140 m
255 m
510 m
800 m
1 km
A class exercise:
This can be started in the classroom, and finished outside.
 Give the learners the following information:
Diameter of the Sun: 1,400,000 km
Diameter of the Earth: 12,800km
 How much wider is the Sun than the Earth?
[Ans: 1,400,000km ÷ 12,800km = 109 times wider (109 times bigger diameter)]

If we made a model solar system with the Sun the size of a soccer ball (25cm
diameter) then how big should the Earth be?
[Ans: 25cm ÷ 109 = about 2mm diameter]
 The Earth is 150 million km from the Sun. How far is this in our scale model?
[Ans: 150 million = 150,000,000 = (150,000,000 ÷ 1,400,000 = ) 107 Sun
diameters; 107 x 25cm = 27m in our model]
Either continue in this way with the rest of the planets, or give the learners the
scale-model distances and sizes of the other planets and get them to find suitable
objects (e.g. rocks) and put their scale model planets the correct distance from
the scale-model Sun.