Break your own question to find the answer. 1. What is the meaning of your weight? 2. Why do not you fall (sink) into a firm floor? 3. But you cannot stand on muddy land. 4. You cannot walk on the water. 5. You cannot float on air. 6. You fall in your imagined tube. Your weight is the force that the resisting body exert on your body, most of the time from under your (sole of) feet. Or reciprocally your body exert to that foreign body. Harsh solid floor stands against you. So you feel weight. 547
Mud exert less so you dip into it until you get to an equivalent force. Water exert less so you feel light and can lift other people easily. On the air you need a very big parachut to gather tiny forces of air to help reduce your accelerating falling and reach to a safe speed. In the imaginary tube there is no other "body" to exert a force to your body and you do not feel anything against your weight. You are weightless! On a scale, a spring stands against you but you can push it, push it, until your forces become equal. Then the spring tells you what is your weight? Now if you create a force that works in favour of you or against you, then you feel less weight or more weight accordingly. Lift and you are not joint together and if lift starts to change its forces you might get different feelings. Your weight is your mass (the matter that you have with wherever you go) times the acceleration that your body experience at any moment. This acceleration most of the time is a constant value that depends on the mass of the earth (almost 10 meters/seconds/seconds). In a theme park they fasten you firmly to the apparatus. In the lift you are not riveted to the lift so they make the changes of acceleration mildly such that you do not feel bad. When the lift accelerates upward it adds to the forces exerted to your body so you feel heavier. When the lift accelerates downward it seems (drastically said) you are on water. You cannot follow it due to having your own inertia so looks it becomes empty under your feet. If it accelerates downward with (10 meter/seconds/seconds) like a theme park or aeronauts training airplanes that you feel completely weightless. You can find similar interesting questions from "University Physics" by <PERSON>. 343