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The Welsh Government funding for Universe in the Classroom ended in June 2018. We have left this site available as an archive of the project.

Scale of the Solar System

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How long does it take to travel to the Moon? How long would it take to reach the edge of the Solar System? In this activity students learn about the size of the Solar System, beginning with the Earth and Moon, and expanding out to encompass all the planets.

Scale of the Solar System Teacher Guide

Scale of the Solar System Student Worksheet

Full Instructions

Learning Objectives
Materials
Background Science

Solar System: The Solar System is made up of the Sun and everything that moves around it. There are eight planets, five dwarf planets and lots of moons, comets, asteroids and meteoroids.

New Horizons: The fastest spaceship ever built is called New Horizons, it launched in 2006 on a mission to reach Pluto in the dark, cold outer regions of the Solar System, and arrived in 2015. New Horizons travels at an amazing average speed of 58,536 kilometres per hour.

Scale Model: A scale model is a model that shows an object that has been made smaller or larger by an accurate amount (called the scale). The scale is shown as: the length used for the model, a colon (:), then the matching length of the real thing.

For example: if a table is 30 cm across, using a scale of 1:30 we would made a table that is 1cm across. If a table was 60 cm across and we used the scale 1:30 again, the model table would be 2cm across.

If a model has a scale of 1:10, any model with the size of 1 would have a size of 10 in the real world, so a model of a room that is 1 metres across would show a room that is 10 metres in real life.

Step-by-Step

1) Hold up your globe and “Moon” from the Universe-in-a-Box toolkit (or ask for two volunteers: one to hold the globe, one to hold the Moon. Ask the class how far they think the Moon lies from the Earth on this scale: should you hold them closer together or farther apart?

2) Let the students guess a few times, then explain that you could fit 30 planet Earths into the space between the Moon and the Earth! It is 384,000 km!

3) Additionally, you could measure the circumference of the globe, multiply this number by 30 and make the distance on the floor to demonstrate the exact distance to scale. When using the Universe in the Classroom Earth ball the moon should be around 12.5-metres.

4) How long do the students think it takes to travel this distance in a spaceship?

5) Can they use a calculator to work out how long it would take to travel to the Moon aboard New Horizons?

384,000 ÷ 58,536: 6.56 hours.

6) Now ask the students what the next closest object is to the Earth? (Answer: Mars.) In the next part of the activity they will learn the size of the Solar System and the distance between the objects.

7) Get a piece of string and draw a thick stripe on the string near one end, this will represent the Sun.

Solar System Scale String

8) Now you can either ask the students to practise their numeracy skills and fill in the Size of the Solar System student worksheet, or just use the values in the table below to demonstrate the distances between the planets in the Solar System.

Planet Distance from the Sun (km) Distance (cm)
Mercury 57 000 000 5.7
Venus 108 000 000 10.8
Earth 105 000 000 15
Mars 228 000 000 22.8
Jupiter 780 000 000 78
Saturn 1 430 000 000 143
Uranus 2 880 000 000 288
Neptune 4 500 000 000 450
Pluto 5 910 000 000 591

9) Ask for a volunteer to measure the distance from the “Sun” to Mercury using the values on the table above (or their own values). Draw a line on the string with the marker pen to represent Mercury.

10) Next, ask a second volunteer to measure the distance from the Sun to Venus. Continue until you have marked off the distance to each planet (plus to dwarf planet Pluto).

11) Now ask for nine volunteers to come and act as the planets. To choose your volunteers, you could ask the students to give you the name of the planets in order from the Sun (e.g. after Mercury, choose the student who names Venus).

Solar System Scale Demo

12) Ask them to stand in the correct order — Sun on the far-left and farthest planet from the Sun on the far-right — behind the string and hold their thumb over the small point representing their assigned planet.

Alternative: Use a piece of scrap paper to create a model of the Solar System. To do this you will need several sheets of A2 or A3 paper cut lengthways into several slivers roughly 5cm across. Fold the paper in half (always fold lengthways). Draw and label Uranus in the crease. Fold both ends to the centre, in one crease draw Neptune, in the other Saturn. Fold to Saturn and draw Jupiter in the crease. Fold to Jupiter, this crease will be the Asteroid belt. Fold to the Asteroid belt, this crease will be Mars. Finally, fold to Mars and then fold again. The three creases, going from Mars to the edge, will be Earth, Venus and Mercury. The very edge of the paper is the Sun. The other end is the location of dwarf planet Pluto.

13) What do the other children notice: Are all the planets equally spaced? Are the planets further from the Sun closer together or further apart? Why do they think this is?

14) If it takes around 7 hours to travel from Earth to the Moon, how long do they think it would take to get to Mars, Jupiter or even Pluto?

15) Ask the students to work out how long it would take to travel to each planet aboard New Horizons using the distances in their table. They will then convert the number from hours to days (by dividing by 24).

Conclusion

Now that you understand the awesome distances in space and why telescopes are such an essential tool in the exploration of our vast Universe, invite the class to use the robotic telescopes to discover the wonders of the cosmos!

Curriculum Links

KS2 Science in the Welsh National Curriculum
”The relative positions and key features of the Sun and planets in the solar system”

Resources

Print media and online resources.

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