Why this experiment is a mistake

To sum up, correct the mistakes on the second floor.

1.When the match is first lit, the wire is not yet red enough to be "ignited", and the match consumes more oxygen.

2. When the match is about to burn out, it should be quickly put into the bottom of the gas collection cylinder not because "when it is about to burn out, it may produce less heat during combustion and cannot ignite the wire", but it should be inserted slowly, so as to ensure that it can fully react with oxygen.

3 Wrap the wire in a spring shape and wrap it around the match.

1.When the match was first lit, the wire was not burned red and could not meet the condition of "ignition", that is to say, even if you put the wire into the oxygen cylinder, the oxygen in the oxygen cylinder did not participate in the reaction of 3Fe + 2O2 = (ignition) Fe3O4 (black solid) according to the experimental requirements, but participated in the reaction of the match stalk combustion, and when the match burned to the wire so that the wire reached the heating condition, the oxygen content in the oxygen cylinder had already failed to meet the experimental requirements, resulting in the failure of the experiment.

2.When the match is about to burn out, the heat released is greatly reduced, and the reaction of 3Fe + 2O2 = (ignition) Fe3O4 (black solid) cannot reach the "ignition" condition, and even if it is prevented, there will be no phenomenon.

3.Please note that the wire used in this experiment is "spiral", that is, we can fold a wire in half from the middle so that the two sides are wound around each other, put the match stem in the gap at the end without a break (the gap is a little larger at the beginning), and then rotate only this end, the gap will gradually become smaller with the number of rotations, and finally the match will be "fastened" (stuck) inside.

1. Why is the match put in the oxygen cylinder as soon as it is lit It is a mistake, because the match that burns in this way will consume more oxygen, and the wire will burn less oxygen.

2. When the match is about to burn out, quickly put it into the bottom of the gas collector cylinder When it is about to burn out, it may produce less heat during combustion and cannot ignite the wire.

3 And I just don't understand what he said before the experiment, how to tie a match at one end of the wire, I don't understand.

First, twist the wire on the burning spoon into a spiral, then take it out, insert a match, light and burn about half of it and insert it into the gas collection cylinder.

1. The experimental device is not adjusted well (such as the rotating disk is not leveled), and the central axis of each part of the system is not adjusted;

2. The swing angle of the rotating disc exceeds 5°;

3. Large timing error;

4. The error of vernier caliper reading.

5. Deviation of balance reading.

Mass rotation inertia simplification:

The magnitude depends on the shape of the object, the mass distribution and the position of the shaft. The moment of inertia of a rigid body has an important physical significance, and it is also an important parameter in scientific experiments, engineering technology, aerospace, electric power, machinery, instrumentation and other industrial fields.

The indication system of the electromagnetic system can be used to measure the small current (galvanometer) or the electric amount (impulse galvanometer) respectively due to the rotational inertia of the coil. In the design of engine blades, flywheels, gyroscopes and satellites, it is necessary to accurately determine the moment of inertia.

That day, I was flipping through a book. Flipping through the pages, I came to a small experimental ......"Is this true? "I think. I saw my father eating oranges, and I saw the balloons on the toy shelf......I immediately pulled my dad to do the experiment.

Dad, let's do a little experiment in the Huaimeng Shed. I said. "First of all, you have to inflate the balloon. We work together, you blow up the balloons, I peel the oranges, and then splash the orange juice on the balloons. "Then I handed the balloon to my father.

Next, peel off an orange and leave the peel behind. Then, squeeze the juice from the orange peel onto the balloon. "I took the orange peel and squeezed it. I thought the balloon would "pop" **, but the balloon didn't react. I tried again, but it still didn't happen.

I was surprised and thought, "What's going on?" Is this experiment fake? I was thinking about it when my dad suddenly said, "I saw that everyone else can make balloons, and our experiment failed because the balloons were of too good quality." ”

Dad told me about the science. It turns out that the skin of oranges contains a certain amount of lipids, which are our common essential oils. This essential oil will swell with the rubber on the surface of the balloon, dissolve the rubber contained in the surface, make the contact part thinner, and make the balloon occur when the air pressure in the balloon remains unchanged.

Although the experiment failed this time, I was happy to understand the scientific principles. I'll see if there are any other fun experiments in the future, and I'll do some more.

1. Failure is the mother of success, and without failed experiments, how can there be next success.

2. Lessons need to be learned in failure.

3. The failure of scientific experiments also reflects that the first book of our understanding of posture is not scientific and profound, and may need to be introspected.

4. Pay attention to possible failures in scientific experiments, especially the safety of scientists.

Analysis: To answer this question, you need to master: the difference between error and error, the difference between the measured value and the true value of the lead is called error, the error can be reduced, but it cannot be avoided; The error is caused by the experimenter's carelessness or non-compliance with the experimental rules, etc., which can be avoided, and the way to reduce the error The difference between the measured value and the true value is called the error The error can be reduced, and the average value is measured many times tomorrow morning.

The error can be reduced, but the error can never be eliminated; The error is caused by the experimenter's carelessness or non-compliance with the experimental rules, etc., which can be avoided Therefore, the answer is: false; Error; Average Comments: This question first examines the definition of error, but also examines the causes of error, the method of reducing error and the difference between error and error, the reason for the error in measurement is generally due to the influence of simplicity or subjectivity, such as different measuring tools, surveyors, etc.

It is impossible for the eyes to estimate very accurately, the measuring instrument cannot be made very accurately, and the temperature and humidity of the environment have an impact on the measuring instrument, which is the cause of error