Our Solar System to Scale
Posted April 18, 2010on:
Tomorrow the students learn just how big our solar system is and just how small we are. We will use the attached worksheet to calculate the percent distance from Pluto for the planets in our solar system and our nearest neighbor, Proxima Centauri.
To make this lesson really stick, we first calculate the percentages, then we lay out a long 100 meter tape outside. Students volunteer to be objects and they get a card with the picture of that object on it. Now we place them on the scale based on their percentage distance. The Sun is at the zero point, Mercury being only 1% of the distance to Pluto is at 1 meter. Earth is at 3 meters, Mars is at 4 meters. Jupiter jumps to 13 meters from the Sun. Pluto is at the 100 meter mark.
In addition to the vast distances, I then discuss how big these objects would be at this scale. The Sun, as huge as it is, is only 2.4 cm or 1 inch in diameter. The Earth would be 0.2 mm, about the size of the period at the end of a sentence.
We discuss how long it takes to get from the Earth to Mars (a 6 month trip by rocket). The people who are Earth and Mars are fighting for space on the tape, it’s crowded near the Sun. After they start to get a sense of scale, I hit them with this. At this scale, the next closes star, Proxima Centauri, is 676 km (420 miles) away, or roughly the distance from Philadelphia to Portland, Maine.