Physical experiment report

Physical experiment report

The same group of people Experimental date September 21, 2003

Experiment name experiment 1 measure the density of the substance

First, the purpose of the experiment:

Master the principle of measuring density by hydrostatic weighing method.
Learn about the characteristics of the pycnometer method for measuring density.
Master the usage of the pycnometer.
Master the use of physical balances.
Second, the experimental principle:

The density of an object is the mass of the object and the volume of the object. In general, there are three methods for measuring object density:

1. For shape regular objects

According to the measurement, the physical balance can be directly measured, the length measuring instrument can be used to measure the relevant length, and then the volume is calculated. Then bring it into the density formula and find the density.

2. Density is determined by hydrostatic weighing for objects with irregular shapes.

Measuring Solid Density According to the Archimedes principle, an object immersed in a liquid is subjected to buoyancy upward from the liquid, and the buoyancy is such. If the solids are placed in the air and immersed in water to balance, the masses obtained are respectively, then

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2 measuring the density of the liquid

Place the objects in the air, water and liquid to be tested, and measure the masses respectively, and, the same is available.

3 measuring the density of paraffin

Paraffin density

---------The quality of paraffin in the air

--------The quality of both the paraffin and the copper ring when they are placed in the water

-------- Paraffin is in the air, the quality of the two is called when the copper ring is placed in the water.

3. Determination of the density of liquid and small solid particles insoluble in liquid by the pycnometer method

1 measure the density of the liquid

.

--------The quality of empty pycnometer

---------The quality of the pycnometer when the liquid to be tested is full

---------The quality of the pycnometer filled with pure water at the same temperature as the liquid to be tested

The density of solid particles is .
----------The quality of the small solid to be tested

---------The quality of the pycnometer and water after filling with water

---------Pycnometer, water and total mass of solids to be tested

Third, the experimental equipment: TW-05 physical balance, pure water, absorbent paper, string, plastic cup, pycnometer

Object to be tested: copper ring and brine, paraffin

Fourth, the experimental steps:

Adjust the balance (1) Adjust the water to rotate the foot screw so that the bubble of the level is at the center.

(2) When adjusting the empty load balance, adjust the adjusting nut at both ends of the beam and start the brake knob to make the balance pointer equal to the middle or the swing number after the balance beam is lifted.

The hydrostatic balance method is used to measure the density of the copper ring and the brine. (1) First, hang the object on the scale hook on the left side of the balance with a thin wire, and use the balance to weigh the copper ring in the air.

(2) Then put a plastic cup filled with pure water on the tray on the left. The copper ring was placed in pure water and the quality of the copper ring in water was weighed.

(3) Pour off the water in the plastic cup, replace the salt water and repeat the previous step, and weigh the quality of the copper ring in the brine.

(4) Substituting the measured data into the formula calculation.

The density of the paraffin is measured by the mass of the paraffin alone in the air, the corresponding quality of the paraffin and the copper ring all immersed in the water, the paraffin hanging into the air, and the quality of the copper ring when immersed in water. Substitute formula calculation.

4. Determination of the density of brine and small liquid insoluble lead strips by the pycnometer method

(1) The quality of the pycnometer.

(2) Measure the mass of the pycnometer filled with pure water at the same temperature as the salt to be tested.

(3) Measure the mass of the pycnometer when filled with salt water.

(4) Measure the quality of the small lead strip to be tested.

(5) Measure the total mass of the pycnometer, water and solid to be tested.

5. Record water temperature, humidity and atmospheric pressure.

V. Information and data processing:

Determination of the density of copper rings, brine and paraffin by hydrostatic weighing

Water temperature water density

atmospheric pressure

136.32 120.55 119.76 49.24 118.74 170.25

Copper block density

Brine density

Paraffin density

Density measurement by pycnometer

Determine the density of brine, water temperature, water density, humidity

atmospheric pressure

26.55 74.57 76.27 0.05

Density of the salt to be tested

Determination of the density of fine lead strips, water temperature, water density, humidity

atmospheric pressure

32.36 74.57 104.20 0.05

Density of lead strip to be tested

Sixth, summary:

The method of measuring the density of solids and liquids by hydrostatic weighing method was mastered by experiments.
Master the use of physical balances and matters needing attention during operation.
Mastered the method of measuring the density using a pycnometer. However, it is difficult to allow the liquid to flow slowly into the bottle along the wall of the bottle, avoiding the generation of bubbles on the wall of the bottle.
By processing the data, I became more familiar with the basic physical concepts such as effective digits and uncertainty, and mastered the calculation method.