Which is denser, wood block or plastic, with the same volume?

Different varieties of plastics, their densities are also different, and the method of determining density can be used to identify plastics; However, at this time, the foamed products should be separated, because the density of the foamed plastic is not the true density of the material. In the actual industry, there are also uses the different densities of plastics to sort plastics. The densities of commonly used plastics are shown in the following table:

Density (g cm3) material Density (g cm3) material. 0 80 Silicone cavity (can be filled with silica to 1 19 1 35 plasticized PVC (containing approximately 40% plasticizer). 0 83 Polymethylpentene 1 20 1 22 Polycarbonate (bisphenol type A).

0 85 0 91 Polypropylene 1 20 1 26 Cross-linked polyurethane. 0 89 0 93 High pressure (low density) polyethylene 1 26 1 28 Phenol formaldehyde resin (unfilled). 0 91 0 92 1 - poly....

It can only be said that sometimes the wood blocks are dense, and sometimes the plastic is dense.

A lot of wood is much denser than water. For example, black ironwood, density, mesquite density, white hardwood. Serpentine density.

There are also very light woods, such as balsha, which are only one-twelfth as dense as black ironwood. The same is true for plastics, the density of polyethylene, polymethacrylate is about the same, and the density of different plastics is also very different.

The density of a block of wood refers to the mass of a block per unit volume and is usually expressed in kilograms of cubic meters (kg m). The density of wood varies depending on factors such as the species, age, growing environment, etc., in general, hardwood is denser and softwood is less dense.

For example, the density of oak is 700-900 kg m, the density of mahogany is 750-880 kg m, the density of pine is 420-550 kg m, the density of birch is 500-700 kg m, the density of beech is 650-800 kg m, and so on.

The density of the wood block is of great significance for the use of wood. Denser wood is generally harder and more wear-resistant than wood with less dense plums, making it suitable for furniture, flooring, doors and windows, and other items that need to withstand heavy pressure. At the same time, the wood with a higher density is also more durable and has a longer service life.

Therefore, when choosing wood, it is necessary to choose the right density according to the specific use and requirements.

The density of a block depends on its properties, and the overall density of wood generally ranges between cubic centimeters.

Because the wood has a certain water absorption, when measuring, the weight of the wood is first weighed. Add an appropriate amount of water to the cup, put the wood into the cup, and then use a weight to press the wood and wait until the wood is fully washed. Factors influencing the change in wood density:

Considering the conditions and use of wood, the main factors affecting the change of wood density and size are split bush species, latewood rate, trunk position, etc.

Varieties of trees: tree species, different tree species, wood structure. There are differences, the ratio of cells and tissues that make up the wood is different, the ratio of cell wall and porosity is also different, and the difference in the internal factors such as selling cherry blossoms causes different wood densities.

Benefits of high density of wood blocks

The air drying density of furniture is related to the wood type selected by the furniture and the process during processing, not the higher or smaller the air drying density, the better. Instead, the moisture content of the furniture is determined according to the air drying density, and the difference is more deformed.

In fact, the oiliness in the wood fibers is dyed for a long time, so that every detail of the furniture has the instinct of not being afraid of water, and in terms of the stability of the furniture in use, it has nothing to do with weight. In terms of actual use effect, the heavier and more stable the furniture, the more inaccurate the conclusion.

There is no unique accident, people will come across some less professional words when choosing solid wood furniture. Seeing that our rubber partition is so heavy, drawn by hand, and not printed, it shows that the wood is very good.

The buoyancy of the wooden block floating on the water is equal to the gravitational force, and half of the immersion in the water indicates that the density of the wooden block is half that of water, which is kilogram liters. So the gravitational force is kilograms

The average density of wood is 1 55 g per cubic centimeter, and the density varies greatly because of the difference in wood species. The heaviest wood in China is clamwood, with a density of 1 128 g per cubic centimeter.

Experimental equipment: tray balance, weights, pins, size two glass containers, graduated cylinders, paraffin steps: 1First, measure the mass of the wooden block with a pallet balance, which is recorded as m2Fill a small glass container with water and place it in a large glass container.

3.Fill the module with paraffin wax and insert the pin into the wooden block 4Then place the wooden block in a small glass container and pinch the pin to completely submerge the wooden block in the water (do not touch the water with your fingers).

5.The discharged water is poured into a graduated cylinder, and the volume v of the water is read, and its size is equal to the volume of the wooden block 6Using the formula mv, the density is calculated.

The wood material is different, the density is different!

The wood material is different, the density is different!

Early nucleoplasm: pine; Birch; Nanmu; Ash; Oak; Elm; Teak; Poplar; maple edge liquid wood; Land-based excavation.

Density (g cm3) ;

Tell the socks to weigh the wooden blocks, then use a needle to completely soak the wood in a cup filled with water, and then take out the wooden blocks. The difference in water between the two cups before and after the comparison is the volume of the wooden block. Density = weight volume.

To reinforce the concept of "density" in class, the teacher can prepare a block of uniform cubic pine wood with two halves butted together, write its volume and mass on the blackboard, and ask what the density of the pine is. It is easy for students to answer according to what they have just learned, and the density is as good as it can be found that its size p wood = one he.

F Bu Xinfei v (kg m,). Then, the block is divided into two from the middle, and the teacher holds up the half of the block and asks the students what the density is, and they will generally think a little and still use the above formula to arrive at p wood 21 m B Lan 1 = flat 1 kg m 3

Finally, the teacher can ask the density of a small piece (of irregular shape) from half a block, and practice has shown that the pupil is generally at a loss, so the volume and mass of the time are unknown, and the above formula is no longer applicable. At this point, the teacher can inspire the students to analyze the physical meaning of density, and clearly point out that mechanical division does not change the chemical properties of the substance (pine), that is, the substance does not change. The density is the physical quantity that reflects the properties of the substance itself and has nothing to do with its volume and mass, so its density is still the original size.

This not only consolidates the definition of density, but also deepens the understanding of the concept of density. @黎绵.

To reinforce the concept of "density" in class, the teacher can prepare a block of uniform cubic pine wood with two halves butted together, write its volume and mass on the blackboard, and ask what the density of the pine is.

Wood block volume: 105ml-80ml=25ml

Mass of wooden blocks: 15g

Density of wood blocks: 15g 25ml = kg per cubic meter.

Material: Pine; Birch; Nanmu; Ash; Oak; Elm; Teak; Poplar; Maple;

Density (g cm3) ;

Different blocks of wood have different densities. Some are smaller than water, some are larger than water.

Block density = block mass Volume Volume = length * width * height.

Density of wood: kilogram meters