Physics experiment is the most important and basic method to study and study physics. It can not only help students to establish perceptual knowledge, but also stimulate students' interest in learning. There are many materials in life that can be used to do physical experiments. Here are some small physics experiments skillfully done with mineral water bottles. First, demonstrate the "inertia phenomenon" Take an empty mineral water bottle, cut off the upper part, fill it with appropriate amount of water, then cover it with a piece of cardboard, put the eggs on the cardboard (as shown in Figure 1), and suddenly tap the cardboard with your fingers. It can be observed that the eggs did not fly away with the cardboard, but fell into the bottle safely. It is precisely because of its own inertia that the egg keeps its original static state and falls directly below. Second, demonstrate the "factors affecting the pressure effect" ① Take an empty mineral water bottle, put a small amount of water into the bottle and put it on a sponge, and immediately you can see that the sponge is sunken; Fill the mineral water bottle with water and put it on the sponge, and you will find that the sponge sinks deeper, as shown in Figure 2. It can be concluded that the role of pressure is related to pressure; (2) Take an empty mineral water bottle, fill the bottle with water, cover the bottle cap, put it on a sponge, and observe the depression degree of the sea surface. Then turn the bottle upside down and observe the depression of the sea surface. By comparing these two depressions, it can be concluded that the effect of pressure is related to the contact area. Third, demonstrate the existence of "atmospheric pressure" ① Take an empty mineral water bottle and fill it with water, and immerse it in the water, as shown in Figure 3A; If you grab the bottom of the bottle and lift it, you will find that the bottle is always full of water before the bottle mouth leaves the water, as shown in Figure 3b. If you drill a small hole in the bottom of the bottle and repeat the above experiment, you will find that the water level inside the bottle is always flush with the water level outside the bottle, as shown in Figure 3 C, which can prove the existence of atmospheric pressure. ② Take an empty mineral water bottle, inject a small amount of hot water into the bottle, shake it, and immediately cover the bottle cap. After a while, I found that the bottle slowly sank inward, which can prove the existence of atmospheric pressure. 4. The demonstration of "The internal pressure of liquid is related to the depth" is shown in Figure 4. Take a mineral water bottle, drill three small holes in its side wall, plug it with a rubber stopper, fill the bottle with water, put the bottle on a table high enough, and then pull out the rubber stopper at the same time. Through experimental exploration, it can be found that the horizontal range of water sprayed from different holes is different, thus demonstrating that "the internal pressure of liquid is related to depth" V. Demonstrate that "liquid has pressure in all directions" Take a mineral water bottle. If you drill many small holes in different directions of the mineral water bottle with small nails, then fill the bottle with water, cover the bottle cap, and squeeze the bottle with both hands, you can see that water is ejected from different small holes in all directions, which can prove that "liquid has pressure in all directions". The intransitive verb "the cause of buoyancy" demonstrates taking a mineral water bottle with an inner diameter slightly smaller than the diameter of table tennis, removing the bottom of the bottle, putting a table tennis ball in the bottle mouth, and then filling the bottle with water. You will find that the water flows out of the bottle mouth, and the table tennis does not float, because "only the upper surface of the table tennis is under the downward pressure of the water, while the lower surface is basically not under the upward pressure of the water", so the table tennis does not float (as shown in Figure 5a); Then plug the bottle mouth with your fingers, and soon you can observe that the table tennis floats (as shown in Figures 5 (b) and 5 (c)), because at this time, "the upper and lower surfaces of table tennis are under water pressure, and the pressure on the lower surface is greater than that on the upper surface". Can demonstrate "the cause of buoyancy", that is, "caused by the pressure difference between the upper and lower surfaces of an object" Seven. Demonstrate the phenomenon of "light refraction" Take a mineral water bottle, cut off the upper part and fill it with water, and insert chopsticks obliquely into the water. Looking obliquely from the water surface, you will find that the chopsticks inserted into the water are bent upward, which can demonstrate the refraction of light (as shown in Figure 6). 8. Demonstrate the effect of force. Squeezing an empty mineral water bottle with both hands will deform the bottle. If the applied force increases, the deformation degree of the bottle will increase, indicating that the role of the force is related to the size of the force. The greater the force, the more obvious the effect of the force. 9. Demonstrate the relationship between fluid pressure and flow. Put two bottles together, put a ping-pong ball on one side of the bottle, and blow into the gap of the bottle from the other side, and the ping-pong ball will not move. Blowing through the gap, the air near the bottle has a high speed and low pressure, while the air outside the table tennis ball has a low speed and high pressure, which will produce a pressure difference inside, so the ball will not move. The relationship between fluid pressure and flow rate can be explained. X. Demonstration of "ups and downs of objects" ① Take a mineral water bottle, cut off the upper part and fill it with clear water (as shown in Figure 7). Eggs will sink in clear water; If salt is put into clear water, if the prepared brine is suitable, the eggs will be suspended in the brine. If you continue to add salt, the eggs will float and eventually float on the liquid surface. (2) Making a float and sink: Take a mineral water bottle and pour a proper amount of water (not full). Then take a small glass bottle for injection, fill it with appropriate amount of water, pour it into a mineral water bottle to make it float (as shown in Figure 8), and then cover the bottle cap. Squeeze the bottle hard and find that the small glass bottle can rise and fall, making a simple floating object. Or stick a layer of rubber film on the bottle mouth without a lid, and then press the rubber film with your fingers, which can also make the small glass bottle float and sink. XI。 Demonstrating experiments related to "convex lens" ① Take a mineral water bottle, which can hold water. In the face of sunlight, you can get "thin" bright bars on the ground, indicating that convex lenses can condense light (convex lenses can condense light). ② Take a mineral water bottle, fill the bottle with water, and then observe the object through the bottle (pay attention to the proper distance between the bottle and the object), and you can see the magnified virtual image of the object, demonstrating that the convex lens becomes a magnified virtual image. The demonstration of "weightlessness" takes a mineral water bottle, fills it with half a bottle of water, and drills a small round hole at the bottom of the bottle with a nail. We can see water spouting from the hole. If the plastic bottle falls freely at this time, we can see that the water is no longer ejected, which verifies the weightlessness of water. Demonstration "The pressure of gas decreases with the increase of volume" Take a mineral water bottle, open a small round hole on the side wall near the bottom of the bottle, seal the small hole with adhesive tape, then unscrew the bottle cap, add water to the bottle, and then tear off the adhesive tape, and water will be ejected from the small hole, as shown in Figure 9. Then cover the bottle cap and tighten it, and soon the water will not be sprayed out of the small hole. At this time, the air pressure above the water surface in the bottle is less than the external atmospheric pressure. This experiment shows that the pressure of gas decreases with the increase of volume. Production of "water rocket" equipment: mineral water bottles, air pumps, bicycle valves, iron wires, rubber plugs, water, etc. The structure of the water rocket is shown in figure 10. Fill the bottle with proper amount of water, plug the cork and put it on the transmitter. Air is pumped into the bottle by an air pump, and the gas pressure above the bottle reaches a certain level. High-pressure gas pushes water and rubber stopper out of the bottle mouth, and the bottle is pushed into the air by the recoil of water. In addition, the mineral water bottle can also be made into a level, which can be used as an overflow cup according to Archimedes principle. As long as students are guided to do experiments and study physical problems with common and cheap equipment (or waste) in teaching, they will not only feel more cordial, but also help to stimulate students' interest in learning and cultivate their practical ability and innovative spirit, thus achieving surprising results.