Galerie de cartes mentales Fluid Mechanics - Outline Relationship between Buoyancy and Gravity of Displaced Liquid
This map shows the main points of this experiment, as well as the skills to understand these main points and the essence of thinking. I hope it can be helpful to everyone.
Modifié à 2023-12-11 15:21:08Explore the relationship between buoyancy and the force of gravity exerted on displaced liquids
Import module
Version 1: (Contact before and after, qualitative to quantitative) What factors are related to the buoyancy of an object is a qualitative rule. Today we will explore the quantitative relationship about buoyancy.
Version 2: Get straight to the point. After the title appears, directly analyze and explore the ideas. How to measure F float and G row.
According to the product tonality and time requirements, choose version 1 or 2. Version 1 focuses on subject thinking, and version 2 hits the key points directly.
content module
Analyze the basic steps according to the problem to be explored (the basic steps refer to the Beijing Normal University version of the textbook because it is simpler and more intuitive than the People's Education Edition textbook. In addition, the video used here is more real and intuitive. Currently, due to time constraints, only pictures can be used to illustrate the experimental process. )
Reflect on key operating points and error analysis in chronological order
1. What will happen if the overflow cup is not full? (The liquid level needs to be replenished first, causing the water that should go to the beaker to stop in the overflow cup. I don’t know whether the product tone likes this kind of poetic and logical expression, or just pursues accuracy and rigor)
2. What will be the consequences of hastily removing the beaker while there is still water dripping from the overflowing cup? (The water that should be counted in the G row has stopped halfway, so the measured G row will be less. It is a special kind of water hanging on the wall)
3. What will happen if the beaker pours water into the keg but it is not poured completely? (The water that should have been included in row G is retained in the small bucket, causing the measured row G to be smaller. The above three "should" are all effects on row G)
4. Can I use a beaker? Where to put the empty bucket in this case? (Involving a kind of process optimization thinking, there is a kind of reverse thinking of purpose inversion method)
5. What impact does the block have on the experiment if it hits the bottom? (The bottom of the cup "pretends" buoyancy to the block's supporting force, making the measured value of buoyancy larger.
6. The object is not completely submerged. Is it possible to complete this investigation? (To reflect on the mainstream immersion practice, and thus get a glimpse of the essence of inquiry, it is only necessary to measure the corresponding F float and G row when entering. It can even be made into a continuous process to measure multiple sets of F float and G row values)
7. Replace the objects with wood blocks with low density. Can Foam Dun complete this investigation? (The essence is the same as 6, it cannot be spontaneously immersed due to the material)
Points 5, 6, and 7 are not seen in the current reference outline. Are they included in other video slices? No need to talk?
Variant device/improvement plan
A small beaker is placed on the connecting frame, and water is discharged into the small beaker while generating buoyancy. The spring dynamometer displays the comprehensive value of the change in buoyancy and the change in G row in the beaker (using analogies to promote students' understanding of the essence, Just like I have 100 yuan on me, and I borrowed 10 yuan, and it returned to my pocket, then the total money on me, 100 yuan, has not changed. When the object is placed in the water, the buoyancy force causes the spring force gauge to decrease. , like borrowed money, the discharged water returns to the cup, increasing the reading of the dynamometer, just like money coming back)
Yitong Baidong's understanding is: Where are the F floating and G rows displayed respectively, and how to compare them?
Trial test
The way to find the fault is to fill the overflow cup
Sort by designing reasonable steps
Analyze the intention/purpose according to the steps and the content section is just reverse thinking, and the content section uses specific numerical values, while the practice section uses letters, from concrete to abstract.
Analyze the impact of "water hanging on the wall" on the experiment. Water hanging on the wall will appear in many ways. a. The beaker is not poured cleanly into the keg. b. The overflow cup is still dripping, and the beaker is removed in a hurry. c. First test the total keg and water, and then tested the keg, resulting in residual water in the keg. The essence depends on the expression of row G and which data is affected by water hanging on the wall, or whether all the water that should be counted in row G has been measured, or whether it has gone elsewhere.
Dynamometer reading and calculation F float or G row
Understand the principles of variant devices/improvement methods, understand the operations, and understand the physical meaning of the results.
Summary module
The experimental details include operational points and error analysis, and a specific summary of which items depend on the previous choices