2. Intoduction  The orbits of some planets are almost perfect circles, but others are not. Some orbits are shaped more like ovals.  Scientists call these oval shapes "ellipses“.  Since the Sun is not at the center of an elliptical orbit, the planet moves closer towards and further away from the Sun as it orbits.

3. Introduction  The place where the planet is closest to the Sun is called perihelion  When the planet is furthest away from the Sun, it is at aphelion.  The words "aphelion" and "perihelion" come from the Greek language.  In Greek, "helios" mean Sun, "peri" means near, and "apo" means away from.

4. How to find Distance?  If you want to find distance, you must know Eccentricity of an Orbit, Semi-major axis, Sun’s diameters when she is in perihelion and aphelion.

5. Formulas  You will need these formulas:  Where a is the mean distance to the Sun,  e the eccentricity of an ellipse.  d a – Sun’s diameter in aphelion  d p –Sun’s diameter in perihelion.  a A - distance in aphelion.  a p - distance in perihelion.

6. Targets  To find distance from Earth to Sun.  To find the eccentricity.  To compare sun‘s diameters in photos.  To compare rezults.  To find out, why is cold in winter.

7. ?

8. Hypothesis  I think, that distance in perihelion and afelion will be very close to Semi-major axis.

9. Work progres  I found 2 Sun pictures, when she is in aphelion and perihelion.

10.  I gauged sun’s diameters. d a =7,9cm d p =8,15cm

11.  I found

12.  I found how many persent differentiate sun diameters in aphelion and perihelion.

13.  I found the eccentricity.

14.  I found a A and a d  For the Earth a = 149,600,000 km Aphelion: Perihelion:

15. Why is cold in winter?  I found out why is cold in winter. Earth reaches perihelion, its closest approach to the Sun and when you might think it should be warmest, in January - the middle of winter in the Northern Hemisphere! The difference in distance is not the cause of our seasons. Instead, seasons are caused by the tilt of Earth's axis.

16. Results NameReal size My size Perihelion 147 098 074 km 147 264 159 km Aphelion 152 097 701 km 151 931 614 km Eccentricity 0,016 710 219 0,0156

17. Inference MMy Hypothesis had reasserted. NNow I know what’s mean eccentricity, perihelion and aphelion. II know how to find eccentricity, perihelion and aphelion.  I know why in summer are warm and why in winter are cold. IIf you want to fly in the Sun, you must fly in winter, because distance is the shortest in winter.

18. Thanks