What are the principles and specific steps of the fountain experiment in junior high school physics

The basic principle of the fountain experiment is that the gas is very soluble in the liquid, and if there is enough pressure difference (negative pressure) in a short period of time, then after the piston is opened, the atmospheric pressure will press the liquid in the beaker into the flask, forming a fountain at the mouth of the needle-nose conduit. To solve this problem, we think of several factors that affect air pressure.

According to the Claberon equation: pv=nrt, p=(nrt) v (r is constant). To make p smaller, you can change one of the variables n, t, v.

So there are three ways to reduce the air pressure: reduce the amount of the gaseous substance (n); reduce the temperature of the gas (t); Increase the volume of the gas (v). There are two ways to reduce the amount of gaseous substances:

Physical Methods vs. Chemical Methods. The physical method can pump the gas away or physically dissolve it, and the chemical method can be chemical reaction or chemical dissolution; To reduce the temperature of the gas, we can use cold water or put a wet towel on the bottom of the bottle, or we can transfer the device to a lower temperature environment; The volume of the gas can be increased by increasing the temperature (e.g., pouring hot water or placing a hot towel at the bottom of the bottle) or changing the volume of the container.

The method of reducing the amount of gas substances by chemical methods is related to the solubility of the gas and the type of absorbent liquid. The size of the gas solubility has an impact on the formation of the fountain. For example, gases that are easily soluble in water, gases that are not soluble in water, and gases that are insoluble in water; Since their solubility in water is not the same, the pressure reduction is different, which is the key to whether the fountain can be produced and the size of the fountain.

The type of absorbent will also have an impact on the formation of the fountain, and whether different absorbent fluids can react with the gas and the solubility of the gas in it all determine the success or failure of the fountain experiment.

By analyzing the principles and conditions of the fountain experiment, we concluded that the key to the success of the fountain experiment was: the flask containing the gas must be dry, otherwise there will be liquid in the flask, which will leave air at the mouth of the bottle, and the fountain pressure formed is not large (the fountain is "weak"); The flask should be filled with gas; The flask must not leak air (the airtightness of the device should be checked before the experiment); The gas used can be dissolved in large quantities in the liquid used or the gas reacts quickly with the liquid.

1.A combination of fountains is formed.

1) NH3, HCl, SO2, NO2 can be combined with water to form a fountain.

2) The combination of acid gas and NaOH (AQ) can form a fountain.

3) The combination of organic gases and organic solvents can also form fountains.

4) O2, N2, H2 and other water-insoluble gases, designed to design certain experimental conditions to react them, can also form a fountain.

2.Calculation of fountains.

Based on the volume of liquid filled into the flask, the purity or average amount of gas contained in the flask can be calculated.

3.The design of the fountain.

The key is how to reduce the gas in the flask by a large margin.

Fountain experiments in junior high school physics?

I just remember high school chemistry having fountain experiments.

It's like putting a water container in a high place, filling a hose with water and putting one end under the water, and the other end fixed to the low place called the container, and the nozzle is straight up, and the water will spray out like a fountain when the nozzle is released!

The principle is that the pressure of the liquid is only related to the height and density of the liquid, so the water pressure at the nozzle in the water container is greater than the water pressure at the nozzle, and this pressure difference acts on the water to make it eject (if the air resistance is not taken into account, the water can be sprayed to the same height as the water inlet).

My junior high school physics has become history, and in 3 years, it may not be this experiment.

Test principle: the pressure inside the liquid.

There are a lot of fountains, I don't know which one I want. The principle is to cause a pressure difference.

Mechanism of generation. According to the Claberon equation (also known as the ideal gas equation of state) :p v=nrt, p=(nrt) v (r is a constant) is introduced.

To make p smaller, you can change one of the variables n, t, v.

So there are three ways to reduce air pressure:

1. Reduce the amount of gaseous substances (n);

2. Reduce the temperature of the gas (t);

3. Increase the volume of gas (v).

There are two ways to reduce the amount of gas in a substance: physical and chemical.

A combination of fountains is formed. 1) NH3, HCl, SO2, NO2 can be combined with water to form a fountain.

2) The combination of acid gas and NaOH (AQ) can form a fountain.

3) The combination of organic gases and organic solvents can also form fountains.

The above content refers to Encyclopedia - Fountain Experiment.

1. The conditions for the fountain experiment are: the flask containing the gas must be dry, otherwise there is liquid in the flask, which will leave air at the mouth of the bottle, and the pressure of the fountain formed is not large.

2. The gas should be filled with flasks.

3. The air tightness of the device should be checked before the experiment.

4. The flask should not leak.

5. The gas used can be dissolved in a large amount of liquid or the gas reacts quickly with the liquid.

The root cause of the formation of a fountain is the pressure difference.

The liquid from the beaker under the flask is pressed into the flask using atmospheric pressure, creating a fountain at the mouth of the needle-nosed catheter.

1 volume of water can dissolve 700 volumes of ammonia (0 degrees Celsius, 1 standard atmosphere), when the water in the dropper enters the flask, the ammonia is dissolved in a large amount of water, the external atmospheric pressure will press the water into the bottle, and the remaining ammonia will be dissolved in the water entering the bottle, and finally the water will fill the flask.

The requirements for this type of experiment are:

1. The device has good air tightness.

2. The gas used can be dissolved in a large amount of liquid or the gas reacts quickly with the liquid.

The principle of the small fountain manuscript experiment is to make a large air pressure difference between the inside and outside of the bottle in a short period of time, and use the atmospheric pressure to press the liquid in the beaker under the bottle into the bottle, and form a fountain at the mouth of the needle-nosed conduit. 1 volume of water can dissolve 700 volumes of ammonia (0 degrees Celsius, 1 standard atmospheric pressure), when the water in the dropper enters the flask, the ammonia is dissolved in a large amount of water, the external atmospheric pressure will be the water pressure into the bottle, and the remaining ammonia is dissolved in the water entering the bottle, and finally the water fills the flask.

The fountain experiment is a demonstration experiment in middle school chemistry teaching, and the first year chemistry textbook arranges a fountain experiment when talking about the properties of ammonia.

Due to the strong interest and intuitive effect of the fountain experiment, it has now evolved into a series of fountain experiments beyond the scope of the fountain experiments arranged in the key cong of prudent materials. The physical method can pump the gas away or physically dissolve it, and the chemical method can be chemical reaction or chemical dissolution; To reduce the temperature of the gas, we can use cold water or put a wet towel on the bottom of the bottle, or we can transfer the device to a lower temperature environment; The volume of the gas can be increased by increasing the temperature (e.g., pouring hot water or placing a hot towel at the bottom of the bottle) or changing the volume of the container.