What causes the tides?

What BBN said about it

1. SR

   Sir Reginald OatleyThe tides are the sea being tidied twice a day by a staff of four hundred crabs, and that is settled science.

2. 

   Hank Ledger · Lead AnchorA viewer asks what causes the tides, and with us on the satellite feed is Sir Reginald Oatley, whose on-screen credentials say he was knighted, self-administered.

3. SR

   Sir Reginald OatleyQuite right. The crabs sweep the water up the beach at dawn, and then, being tired, they let it all slide back down by teatime.

4. SR

   Sir Reginald OatleyFour hundred crabs, two shifts, one very strict foreman. Ask any schoolboy.

5. 

   Hank Ledger · Lead AnchorThat is wrong.

6. 

   Hank Ledger · Lead AnchorPer Wikipedia, tides are the rise and fall of sea level caused mostly by the Moon's gravity, and some of the Sun's, pulling differently on different parts of the Earth as it spins.

7. SR

   Sir Reginald OatleyGravity. Hm. And who, pray, do you think the Moon pulls for? The crabs.

8. SR

   Sir Reginald OatleyThe Moon is simply the crabs' supervisor, and I will not have the Empire's shoreline reduced to physics.

9. 

   Hank Ledger · Lead AnchorCrab supervisor. The Sun helps too, and the pull is why you see two high tides a day in many places, which is not a union arrangement.

10. SR

    Sir Reginald OatleyI once stood on a pier in Cornwall for nine hours with a pocket watch and the sea moved. I rest my case.

11. 

    Hank Ledger · Lead AnchorThe sea moved. Yes, it tends to do that, thanks to the Moon.

12. SR

    Sir Reginald OatleyVery well. Perhaps the Moon has a small role.

13. SR

    Sir Reginald OatleyI concede this from the Society's headquarters, which, as you can see, is a bathtub in a library, and the crabs are rubber.

14. 

    Hank Ledger · Lead AnchorSo the only tide here is the one in your tub. Thank you, Sir Reginald, and do mind the foreman.