"Quality" Quality and Density PPT Teaching Courseware

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"Quality" Quality and Density PPT Teaching Courseware

The first part: sorting out new knowledge

1. The mass of an object

The ______ of matter contained in an object is called mass. Mass is a basic attribute of an object. It does not change with changes in the object's ______, ______, ______ and temperature.

[Explanation]Objects and matter are two different concepts. An object is a tangible entity made of matter, and matter is the material that constitutes an object.

2. Unit of mass

In the International System of Units, the basic unit of mass is ______, and the symbol is ______; commonly used units are tons (t), grams (g), and milligrams (mg); the conversion relationship is: 1 t = ______kg = ______g = ______mg.

3. Use of balance

A balance is a tool for measuring mass. The steps for using a balance are as follows:

①Look: Observe the weighing of the balance and the graduation value of the scale where the scale is located. ②Place: Place the balance on the ______ work surface. ③ Dial: Move ______ to the zero mark at the left end of the ruler. ④Adjustment: Adjust __________ so that the pointer is aligned with the central scale line of the indexing plate. ⑤Weighing: When weighing, the object to be weighed is placed on the ______ plate, and the weight is placed on the ______ plate. The balance is balanced by increasing or decreasing _____ and moving ______. ⑥Remember: The mass of the object being measured = the total mass of ______ in the right disk + the mass value indicated by ______.

Tips for using the scale:

The balance should be placed horizontally, and the scale must be returned to zero before leveling.

Do not shift the balance of the scale. It is not feasible to swap the two plates.

Use tweezers to pick up and place the weights, placing them on the left and right in the two plates.

Move the game code to see the pointer. The pointer points to the center to indicate balance.

Read the weight and the swimming code, and add the two values ​​to complete.

Quality PPT, Part 2: Application Examples

Type 1 Quality and its units

Example 1 Regarding quality, which of the following statements is incorrect ()

A． The lunar module's mass decreases from the earth to the moon

B. When a glass of water freezes into ice, its volume increases but its mass remains unchanged.

C. After the glass is broken, its shape changes but its mass remains unchanged.

D. Part of the oxygen in the oxygen bottle is used up, and the mass becomes smaller

Type 2: Estimation of quality

Example 2 It is not allowed to fill in the mass unit "g" after the following sets of numbers ()

A． The mass of a pen is approximately 21.3

B. The mass of a person is approximately 4.2×107

C. The mass of a fully loaded truck is approximately 8.0×106

D. The mass of a book is approximately 2.5×102

[Method guidance]Methods for estimating object mass

The prerequisite for correctly estimating the mass of an object is to be familiar with the mass of common objects in life. Commonly used units of mass in life are kilograms and taels. Sometimes the quantities in kilograms, grams, etc. in the questions can be converted into kilograms or taels to facilitate correct estimation.

Type 3: Measurement of quality

Example 3 2018·Lanzhou Students in an interest group conducted a research experiment: the use of scales.

(1) Place the balance on a horizontal platform and move the scale to the zero mark of the scale. When the beam is stationary, the pointer points to the right side of the central scale line on the index plate, as shown in Figure 6-1-1A. In order to balance the beam in the horizontal position, the balance nut at the right end of the beam should be moved to the ______ (optional "left" or "right") end.

(2) Place a pencil case on the left plate of the adjusted balance. After the balance is balanced again, the positions of the weights and slides placed on the right plate on the scale are as shown in Figure B, then the mass of the pencil case is_ _____g.

[Rule Summary]In the process of adjusting the balance of the balance, adjust the balance nut in the opposite direction of the pointer deflection, that is, if the pointer moves to the right, adjust the nut to the left; if the pointer moves to the left, adjust the nut to the right. When reading, the mass of the object is equal to the sum of the mass of the weight and the scale value corresponding to the scale on the scale.

Quality PPT, Part 3: Class Feedback

1. The basic unit of mass is ( )

A． g

B. mg

C. kg

D. t

2. Which of the following statements about quality is correct ()

A． After the plasticine is kneaded into a clay figure, the mass becomes smaller.

B. After the white sugar is heated and drawn into marshmallows, the mass becomes larger

C. 1 kg of cotton and 1 kg of iron, the mass of the iron is greater

D. Physics textbooks delivered by express delivery from Wuhan to Qianjiang, the quality is the same

[ Analysis The quantity has not changed, so the mass remains the same, option B is wrong; the masses of 1 kg of cotton and 1 kg of iron are equal, option C is wrong; the physics textbooks are just in different locations in Wuhan and Qianjiang, the quantity of matter has not changed, so the mass remains the same , option D is correct.

3． Complete the following unit conversions.

(1)5.4 t=________kg=________g.

(2)2800 mg=________kg.

4. Fill in the appropriate mass unit on the line.

(1)The mass of a junior high school student is about 45___________.

(2)The mass of a table tennis ball is approximately 2.8___________.

(3)The mass of an elephant is approximately 5.8___________.

(4)The mass of an egg is close to 50___________.

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"Quality" Quality and Density PPT courseware download:

"Quality" Quality and Density PPT courseware download Part 1: Classification practice of knowledge points Knowledge point 1 Quality 1. The amount of _____ contained in an object is called mass, represented by the symbol ____. The international unit of mass is _____, represented by the symbol ____. quality..

"Quality" Quality and Density PPT download:

"Quality" Quality and Density PPT Download Part One: Basics of Knowledge Points Knowledge Point 1 Quality 1. Please fill in the appropriate units after the numbers below. (1) The mass of a stamp is about 50 mg; (2) The mass of a truck of steel is about 5 t; (3)..

"Quality" Quality and Density PPT:

"Quality" Mass and Density PPT Part One: Preview Perception 1. Quality 1. Concept: How much _________ does an object contain. 2. Unit: 3. The mass of an object does not change with its shape, state and position. 2. Measurement of quality 1. Measuring tools: measuring..

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Update Time: 2024-09-07

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

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