Simple device for testing buoyancy of foam block

Abstract

A simple device for testing the buoyancy of a foam block consists of a bracket, a pulley with a fixed single side, a flat water tank, a clamp, the foam block, a rope and a dynamometer, buoyancy of thefoam block is tested by the buoyancy test support. The pulley is disengaged from bottom of the water tank, a pulley with a fixed single side is fixed on a cross rod at the bottom end of the bracket;a rope for connecting the foam block and the dynamometer bypasses the pulley groove, the pulley bottom surface groove with one fixed side and the two pulleys with one fixed side at intervals, and therope is wound into a U shape, so that the problem of interference caused by friction and collision between a lifting rope connected with the dynamometer and the foam block is prevented, and the problems of difficulty in plasticine fixation and difficulty in stringing are solved when the rope is built outside the water tank; the support is vertically immersed in a water tank for testing, water saving demonstration is performed, and buoyancy is tested; the device is simple in design, convenient to operate, short in experiment time, high in success rate, simple to manufacture, low in cost, reusable and more effective in teaching demonstration.

Description

Technical field: [0001] The invention belongs to an experimental device, in particular to a simple device for testing the buoyancy of a foam block. Background technique: [0002] The content of the buoyancy test in Unit 1, Lesson 5, and Lesson 5 of the second volume of the textbook for the fifth grade of science in the textbook. A test designed to reveal how much buoyancy a floating block of foam experiences when submerged in water, or a test of the buoyancy of blocks of foam of different sizes immersed in water. It is known that the larger the volume of an object immersed in water, the greater the amount of water it displaces and the greater the buoyant force it receives. The textbook provides a method of sticking the pulley with plasticine at the bottom of the tank and changing the direction of the pulling force to test the buoyancy of the foam block immersed in water. There is no matching experimental equipment in the laboratory and on the market. The self-made equipmen...

AI Technical Summary

Problems solved by technology

The self-made equipment according to the requirements of the book is not effective in this experiment, and the success rate of the experiment is low. The problems here are:

[0003] ①. Plasticine fixing problem: In the sink, the plasticine is difficult to fix in the water, the plasticine is not firmly attached to the bottom of the container, and it is easy to pull the plasticine and the pulley together

[0004] ②. The size of the water tank: To make the dynamometer measure the tensile force on the foam block, a relatively deep water tank is needed. If a large water tank is used, water will be wasted. The mud is not easy to be placed at the bottom of the bottle, the space is narrow, and the rope operation is more difficult

[0005] ③. The problem of threading and pressing the rope: the rope is easy to come out of the groove of the pulley. In the sink, it is difficult to thread the rope in the gap under the pulley. The thread falls off, and it is even more difficult to press the rope into the groove of the pulley.

It is not easy to thread and press the rope at the bottom of the tank with water, and it takes a lot of effort to thread the rope repeatedly

[0006] ④. Mutual interference between the rope of the pull-up dynamometer and the pull-down foam block: When the dynamometer is pulled up, the angle of inclination formed by only one pulley is small, and the rope of the pull-up dynamometer and the foam block pulled down Blocks collide with each other and interfere with each other, resulting in test errors

[0007] The experimental teaching is limited by time, in a hurry, due to the equipment, the experiment is hastily done, the experimental demonstration becomes an explanation experiment, and the experimental effect is not achieved.

In short, the success rate of the experiment is low, but the simple experiment is troublesome.

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