① Water flows out from two small holes, and the water flowing out from the lower hole is the most urgent, indicating that the pressure of the liquid is related to the depth, and the deeper the depth, the greater the pressure;

② Inject a small amount of hot water into the empty mineral water bottle, shake well and immediately cover the bottle cap. After a while, it was found that the bottle slowly sank inward because the air pressure decreased after internal cooling, and the external atmospheric pressure crushed the bottle;

(3) The greater the applied force, the greater the deformation of the bottle, indicating that the role of the force is related to the size of the force. Under the same circumstances, the greater the intensity, the more obvious the effect;

④ The mineral water bottle is placed on the sponge, and the sponge sinks. When the mineral water bottle falls, the sponge sinks more obviously, which shows that under the same pressure, the pressure is related to the stress area, and the smaller the stress area, the greater the pressure.

⑤ Blow the side of the mineral water bottle hard to make it roll, but blow the bottom hard to make it difficult to slide. The former is rolling friction and the latter is sliding friction, which shows that the rolling friction is less than sliding friction under the same pressure.

Therefore, the answers are: ① depth; ② Atmospheric pressure; ③ size; ④ area; ⑤ Rolling friction is less than sliding friction.