SUBMARINE

WHAT IS SUBMARINE?                                                                                                                          THE IRISH INVENTOR JOHN PHILIP HOLLAND BUILT A MODEL SUBMARINE IN 1876 AND A FULL SCALE ONE IN 1878 ,FOLLOWED BY A NUMBER OF UNSUCCESSFUL ONES.IN 1896, HE DESIGNED THE HOLLAND TYPE VI SUBMARINE.THIS VESSEL MADE USE OF INTERNAL COMBUSTION ENGINE POWER ON THE SURFACE AND ELECTRIC BATTERY POWER FOR SUBMERGED OPERATIONS.

                                                                                                                                                                            HOW DOES A SUBMARINE SINK AND FLOAT?                                                                                                                           A SUBMARINE USES THE RELATIONSHIP BETWEEN DENSITY AND FLOTATION.WATER IS PUMPED INTO THE BALLAST TANKS OF THE SUBMARINE.THIS INCREASES ITS MASS,THIS CAUSES THE SUBMARINE TO SINK.WHEN WATER IS PUMPED OUT OF THE BALLAST TANKS ,THE SUBMARINE BECOMES LIGHTER.IT RISES TO THE SURFACE OF THE SEA.THUS,BY CONTROLLING THE MASS OF WATER IN THE BALLAST TANKS,THE SUBMARINE CAN BE MADE TO SINK AND FLOAT.