2. Astronomy: From planets to the Universe

3. Our solar system The sun is a very ordinary star among thousands of millions of other stars in the Milky Way galaxy. It has a planetary system made up of planets, dwarf planets, moons, asteroids, comets and other material left over after its formation. Lets start with our Solar System

4. Planets in our solar system: Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

6. Solar system What do you think is incorrect about this representation of the solar system? They are misleading as they do not show the relative sizes of our sun and the planets or the vast distances between them.

7. Task : Constructing a model. To appreciate the relative size of the sun and the planets we shall make a model. Using the items suggested on the chart, arrange them in the correct order and make labels for them.

8. BodyDiameterDistance to scale from one object to next / m Distance to scale of object to sun / m Suggested object Sun24010-Basketball Mercury0.8910Pinhead Venus2719Peppercorn Earth2.11326Peppercorn Mars1.19539Pinhead Jupiter24112134Grape Saturn20249246Marble Uranus8281493Dried pea Neptune7.8244774Dried pea

10. Now that we have represented the solar system, we must try and understand the scale. Calculate the approximate scale if: If the earth is 12,724 km wide and in this model it is 2.1 mm The sun is 1,391,900 km in diameter whereas the basketball is only 240 mm in diameter.

11. The scale is approximately 1: 6,000,000. This means that 1 m will represent about 6,000,000 km. ( every cm represents 60,000 km) To demonstrate this effectively we shall go outside and use a trundle wheel to space out the distances between the planets.