The secret to getting ketchup out is to give it a good shake, then hit the heel of your hand "upwards" on the top of the bottle, near where the neck meets the body (on the 57 or not, doesn't really matter). The upward force is what counts, and it somehow gets the ketchup to come out relatively smoothly. Most people strike downwards, and that's why it doesn't work. If you don't believe me, try it! Learned this trick from my uncle.
I'm guessing the functional principle here is somehow related to vacuums, those pop-tops on the new Miller beer cans, etc.
- An object will remain in the same state of motion (or rest) unless acted on by a force.
When you hit up on the bottle, you are applying a force primarily to the bottle. The force is applied to the sauce inside to a much lesser degree, so it stays closer to a state of rest. Therefore if the bottle goes up and the sauce stays at rest, it has the effect of moving the sauce down to the neck of the bottle.
My "secret" is to hold the bottle in my hand and swing my arm in a large arc, using centrifugal forces to pull the ketchup towards the mouth of the bottle.
I'm guessing the functional principle here is somehow related to vacuums, those pop-tops on the new Miller beer cans, etc.