Togheter with students on the blackboard presents the proper order of the planets and write their names.
Practise
4.  Teacher asks students to look at the names of the planets and to remeber the order he asks them to write a sentences in which all the words with start with the letter from the planets.
MVEMJSUN
Example:  "Many Velociraptors Easily Munch Juicy Steaks, Napping Under Nebulas."
My Very Energetic Monkey Jumps Swiftly Upstairs Now."
5. Teachers shows the students balls ( "polystyren ) of different sizes and asks which represents which planet.
6, There is a short discussion about the size of the planet. Teacher corrects the students knowledge and provides the correct information about the sieze of the planets. Together with students the pick up the proper balls.
 Close up: Students are plaing the" Blooket" game in groups about the size of planets and solar system,
Link to the game:
https://dashboard.blooket.com/set/6058583541ed3000236b1def
Link to the general website
https://dashboard.blooket.com/discover
7. Continuation of the lesson, 
Students create their own solar system, individually or in groups, preferably during the next lesson.
Before givinh them this task, dicuss with students, what materials they can use, what could represent gas planet,rocks? 
Students should:Create appropriately sized spheres or larger balls (2-3 each) representing the planets. Theycan also use ready-made lightweight styrofoam balls or balls of different sizes, paint them appropriately, or cover them with paper, foil, fabric, etc. When making the planets, pay attention to the size of each planet, its color, and the materials it is made of: rocks, gases, ice, etc.
Then place your planets accordingly: starting from the central position of the Sun and replicating the order of planets in the Solar System.