We use Tomato sauce very frequently in day to day life. We use it with yummy long noodles, bread, flavouring and so on. We can’t imagine without tomato sauce.
Tomato sauce is a highly viscous paste made from tomatoes, spices and various other additives. Hence, the sauce can only move if it is shaken or sufficient force is applied .
Everyone knows from pouring water out of a bottle that the liquid that leaves the bottom of a bottle has to be replaced by air bubbling through the water from the open end of the bottle. This is how anything comes out of the bottle at the very first place.
Tomato sauce, however, is viscous to allow air bubbles to pass through it easily. This is why a vacuum forms in the bottom of the bottle when the sauce moves away from it. As a result, a pressure difference is created that works against the force of gravity (which is pulling the sauce downwards).
When tomato sauce stubbornly refuses to leave the bottle there are several ways of getting it out.
Plastic bottles of sauce are flexible and can be squeezed to eliminate the vacuum. So there is no more pulling force and sauce comes out.
Sauce in rigid bottles, on the other hand, can be helped along by hitting the base of the bottle, sometimes with disastrous results.
The third method helps with both types of container-simply insert a drinking straw deep into the bottle so that air can pass through the tomato sauce to the bottom.