1, because the reaction of white vinegar and baking soda will produce carbon dioxide gas. Bubbles float on red beans, which are buoyant and red beans rise. As the red beans surfaced, the bubbles burst, and the buoyancy of the red beans increased again, so they sank. In this way, red beans are really like dancing.

2. When baking soda meets white vinegar, it will react to produce carbon dioxide, and bubbles will attach to red beans to increase buoyancy and become the swimming ring of red beans. In addition, the constantly reacting upwelling bubbles will bring the red beans to the water surface to touch the air or smash them after hitting other red beans, and they will turn over and over because of their overweight body.

Experimental process: Observe the scientific changes, experimental changes and principles of red beans in measuring cups.

Experimental principle: baking soda and white vinegar produce carbon dioxide gas and form bubbles. Red beans are light in weight and small in size, and bubbles are attached to them, so their buoyancy is greater than gravity, so they float to the surface under the action of buoyancy. After floating to the liquid surface, the bubbles burst due to contact with air, and the buoyancy of red beans is less than gravity, and finally they sink into the bottom of the cup. In this way, we will see red beans that can "dance"

The purpose of the experiment:

The direct purpose of scientific experiment is to verify whether a hypothesis or theory is correct, because scientific experiment itself is a kind of social practice, and practice is the only criterion for testing truth. The ultimate goal of scientific experiment is to greatly promote the development of productive forces and create material and spiritual wealth as much as possible.

Of course, we should actively encourage students, especially some senior students, to innovate boldly and explore some topics with real scientific value, but in fact, most experiments designed by primary school students have long been scientifically concluded, but the experimental results are not our only purpose.