"Density" Quality and Density PPT Teaching Courseware

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"Density" Quality and Density PPT Teaching Courseware

The first part: sorting out new knowledge

1. Explore the relationship between mass and volume of matter

The ratio of the mass to the volume of the same substance is ______, that is, the mass and volume of the same substance are related to ______; the ratio of the mass to the volume of different substances is generally ______.

2. Density of matter

1. Meaning: The ratio of the mass and volume of a substance reflects a characteristic of the substance. In physics, the physical quantity ______ is used to represent this characteristic.

2. Definition: In physics, the ratio of the ______ of an object composed of a certain substance to its ______ is called the density of the substance. Density is numerically equal to ______ of object units ______.

[Instruction]Using the ratio of two quantities to define a new physical quantity is a commonly used method in physics. This method is called the "ratio definition method".

3. Formula: ρ=______.

4. Unit: In the International System of Units, the basic unit of density is ______, and the commonly used units are ______. The conversion relationship between them is: 1.0 g/cm3 = 1.0×103 kg/m3.

3. Application of density knowledge

1. Identify substances

As long as the ______ and ______ of the object are measured, and then the density formula ρ = ______ is used to find out its density, the type of substance can be determined by comparing it with the density table.

2. Find the mass of an object given its volume

For some objects whose mass is inconvenient to be directly measured, as long as the ______ of the object is measured, and then the ______ of the materials that make up the object are found, the mass of the object can be found by using m = ______.

3. Find the volume of an object with a known mass

For some objects whose volume is inconvenient to be directly measured, as long as the mass m of the object is known, and then the density of the material composing the object is found, the volume of the object can be calculated by using V = ______.

Density PPT, Part 2: Application Examples

Type 1: Relationship between mass and volume of matter

Example 1: In order to study certain properties of substances, students found wax blocks of different sizes and dry pine wood of different sizes for experiments, and obtained the data shown in the following table:

(1) Please use images to graphically represent the change of the mass of a substance with its volume in Figure 6-2-2.

(2) What conclusions can you draw by analyzing the image in (1)? __________________________________________________.

(Required to write two items) In physics, ______ is usually used to represent this characteristic of matter.

[Experimental Instructions] (1) Wax blocks and dry pine wood were selected in the experiment to compare and conclude that the ratios of mass and volume of different substances are different; in order to make the conclusion more general, conditions permitting In this case, it is best to choose a third substance for experiment, so that the conclusion will be more convincing.

(2) In the experiment, more than three sets of data are measured for each substance in order to find general rules.

Type 2: Understanding of density of matter

Example 2 Regarding density, which of the following statements is correct ()

A． Density is directly proportional to the mass of an object and inversely proportional to its volume

B. Density is a property of matter and has nothing to do with the mass and volume of the object

C. Density has nothing to do with the state of the object

D. Density has nothing to do with the temperature of an object

[Analysis]Density is a characteristic of matter. For a certain substance, its density does not change with changes in mass and volume. The same substance has different states and different densities. For a certain mass of substance, the volume changes with changes in temperature, so the density changes accordingly.

Type 3: Calculation of Density

Example 3 Figure 6-2-3 shows the relationship between the mass and volume of two substances, A and B. The following statement is correct ()

A． The density of substance B is greater than that of substance A

B. The mass of substance B with a volume of 50 cm3 is 35 g.

C. The volume of substance A with mass 25 g is 30 cm3

D. When two substances A and B have the same mass, the volume of substance B is larger

[Method guidance] m-V image problem analysis

(1) When comparing the densities of different substances based on the image of the relationship between mass and volume, two methods can be used: ① Compare the mass of the same volume, and the one with greater mass will have greater density; ② Compare the volume with the same mass, and the smaller volume will have greater density.

(2) When using the m-v image to calculate density, find an easy-to-read point on the image, read the corresponding mass and volume, and then calculate according to the density formula.

Density PPT, Part 3: Class Feedback

1. Which of the following density calculation formulas and its deformation formulas is wrong ( )

A． ρ=mV B. m=ρV

C. V＝mρ D. V＝ρm

2. In the International System of Units, the basic unit of density is ()

A． kg B. m3 C． kg/m3 D. g/cm3

3． Which of the following is correct about the density unit conversion relationship ( )

A． 1 g/cm3＝1 kg/m3

B. 1 g/cm3＝102 kg/m3

C. 1 g/cm3＝103 kg/m3

D. 1 g/cm3＝10-3 kg/m3

4. People often say "Iron is heavier than wood." What it really means is ()

A． Iron is denser than wood

B. Iron has greater mass than wood

C. Wood is lighter than iron

D. The mass of iron and the mass of wood are actually the same

[Analysis] "Iron is heavier than wood" is an inaccurate statement in daily life. Its real meaning is not that the mass of iron is greater than the mass of wood, but that the same volume of iron and Compared with wood, the mass of iron is greater, that is, the density of iron is greater than the density of wood.

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"Density" Quality and Density PPT courseware download:

"Density" Mass and Density PPT courseware download Part 1: Classification practice of knowledge points Knowledge point 1 The relationship between the mass and volume of the same substance 1. In order to study certain properties of matter, the teacher and classmates conducted experiments together and recorded the data as follows: (1) Please use...

"Density" Quality and Density PPT download:

"Density" Mass and Density PPT Download Part 1 Contents: Knowledge Points Basic Knowledge Point 1 The relationship between the mass and volume of the same substance 1. In order to study a certain characteristic of a substance, a student used water and alcohol to conduct experimental investigations, and the measured results are as follows Data: (1) In the figure..

"Density" Quality and Density PPT:

"Density" Mass and Density PPT Part One: Preview Perception 1. The relationship between the mass and volume of a substance 1. For the same substance, the ratio of its mass to its volume is ________. 2. The ratio of mass to volume of different substances is generally ________. 3..

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Update Time: 2024-10-18

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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