1. GRYMOEDD FORCES Is gravity real - or does the Earth just suck? A yw disgyrchiant yn bod – neu a yw’r Ddaear yn sugno?

2. 2 Sir Isaac Newton

3. 3 Pa ffrwyth ? Which fruit ?

4. 4 Newton?

5. 5 Grym yw disgyrchiant Gravity is a force When gravity pulls something towards the Earth – - we call this force the weight. Wrth i ddisgyrchiant dynnu rhywbeth tuag at y Ddaear - - y pwysau yw’r enw a roddir ar y grym hwn.

6. 6 Mesurir grymoedd mewn Newtonau Forces are measured in Newtons Pwysau afal = tua 1 Newton Weight of an apple = about 1 Newton

7. 7 Dewch I chwarae gêm! Let’s play a game !

8. 8 Codi pêl ping pong Lifting a ping pong ball gwelltyn straw Sugno ! Suck !

9. 9 pêl ping pong yn disgyn ping pong ball falling Mae’r saeth yn cynrychioli grym disgyrchiant The arrow represents the force of gravity

10. 10 The ball does not fall when your sucking force = force of gravity sugno / suck disgyrchiant gravity How have I shown this ? Nid yw’r bêl yn disgyn os yw’r grym sugno = grym disgyrchiant gwelltyn straw

11. 11 Which diagram shows the sucking force equal to the force of gravity? Pa ddeiagram sy’n dangos grym sugno sy’n gyfartal â grym disgyrchiant? gwelltyn straw gwelltyn straw gwelltyn straw sugno / suck disgyrchiant gravity

12. 12 The ball does not fall when your upward force = force of gravity Nid yw’r bêl yn disgyn os yw y grym gwthio i fyny = grym disgyrchiant disgyrchiant gravity sugno / suck gwelltyn straw

13. 13 Disgyrchiant ochr arall Gravity down under y byd Nid yw pobl yn syrthio oddi ar y Ddaear People do not fall off the Earth

14. 14 - dau wrthych sy’n cael eu gollwng ar yr un pryd -two objects dropped at the same time

15. 15 Ar y Lleuad Apollo 15On the Moon http://nssdc.gsfc.nasa.gov/planetary/image/featherdrop_sound.mov A heavy geological hammer and a falcon feather were dropped from the same height. They hit the lunar surface at the same time. astronaut David Scott NASA pictures Cafodd morthwyl daearegol trwm a phluen hebog eu gollwng o’r un uchder. Gwnaeth y ddau daro wyneb y lleuad ar yr un pryd.

16. 16 Y Lleuad The Moon Y Ddaear The Earth

17. 17 Y Ddaear The Earth Y Lleuad The Moon

18. 18 Ar y Lleuad On the Moon NASA pictures

19. 19 Esgidiau trymion iawn - Pam? Very heavy boots- Why? Answers? No gravity on the Moon Weightless on the Moon To stop them floating away They weigh very much less than on Earth To stop huge bounces The Moon’s gravity is very much less than the Earth’s gravity Atebion? Dim disgyrchiant ar y Lleuad Dibwysedd ar y Lleuad Rhag ofn iddynt arnofio i ffwrdd Maen nhw’n pwyso llawer llai nag y maen nhw ar y Ddaear I osgoi bownsiadau anferth Mae disgyrchiant y Lleuad yn llawer llai na disgyrchiant y Ddaear

20. 20 DISGYRCHIANT GRAVITY Things fall Things have weight Things stay in place Mae pethau’n syrthio Mae gan bethau bwysau Mae pethu’n aros yn eu lle

21. 21 Dim Disgyrchiant No Gravity Would an apple fall? Would things stay on earth? What would happen? What? Why? How? A fyddai afal yn syrthio? A fyddai pethau’n aros ar y ddaear? Beth fyddai’n digwydd? Pam? Beth? Sut?

22. 22 ……keep asking questions -like Newton! …….aliwch ati i ofyn cwestiynau -fel Newton !