Method for reducing and increasing pressure presentation. Pressure

Class: 7

Presentation for the lesson

Back forward

Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested in this work, please download the full version.

Each slide appears on the ID screen when you click it.

Each slide element also appears on click as needed.

Students work with slides 5 and 17 at the board (each picture appears as the student explains and responds by clicking)

The task “to prepare a historical account of Blaise Pascal” was assigned to the students in advance.

Using a presentation allows you to improve the clarity of the material being studied, which contributes to the development of cognitive interest in the subject.

The purpose of the lesson:

Educational: To form general ideas about pressure, pressure force, its units and methods of changing pressure;
Developmental: development of experimental skills, skills, logical thinking, substantiation of one’s statements, development of group work skills, justify the need to increase or decrease pressure;
Educational: formation of independent work skills, nurturing a sense of cooperation in the process of jointly completing an educational task.

Equipment: multimedia projector, computer, presentation.

Lesson type: combined.

During the classes

I. Organizational moment.

(slide 1, 2)

II. Repetition of learned material.

1. Teacher:

“The elephant came out onto the forest path,
He stepped on an ant's foot.
And he very politely said to the ant:
“You might as well step on mine.” (slide 3)

Questions for students:

“Will the end result be the same?”
What determines the action of one body on another? (slide 4)
Answer: by force.
What determines the force applied to the body?
Answer: depending on the module, direction and point of application.
What happens to a body if a force acts on it?
Answer: a body can change its speed or become deformed.

The student goes to the interactive whiteboard (ID) and shows that the result of the force (deformation of the body) depends on the magnitude of the force. (slide 5)

Tell me, the result of a force depends only on its magnitude, point of application and direction?

(students discuss the pictures on slide 6, 7 and draw a conclusion)

Students' conclusion:

It also depends on the surface area perpendicular to which it acts.

III. Learning new material.

(slide 8)

Teacher:

1. A physical quantity that characterizes the action of a force applied perpendicular to the surface on which it acts is called pressure.

Question: What do you need to know to find the pressure?

Answer: force and area.

(The teacher introduces the designation “pressure” and, together with the students, writes down the formula for calculating pressure and the unit of pressure measurement)

2. The student provides historical information about Blaise Pascal (slide 9)

3. Pressure units used in practice (slide 10):

(independent work of students with subsequent testing)

1 kPa=….
1 µPa=…
1 mPa=…
1 hPa=….
1 MPa=

4. Derivation of formulas for calculating force and surface area (slide 11)

(horizontal bar – division, vertical bar – multiplication)

5. Physical education minute (slide 12)

Teacher: Please stand up.

-Are you putting pressure on the floor now?

- Will the pressure change if we: raise our hands, spread them apart?

- Is it possible to increase this pressure?

- How to reduce the pressure?

6. So, the physical education lesson showed us that pressure is not a constant value and can be changed (slide 13)

IV. Reinforcing the material learned

1. Look at the pictures. Formulate the problem and explain (slide 14)

(students independently compose problems based on the drawings and solve them)

2. Answer the questions (slide 15)

3. Work on ID (slide 17)

Look at the bodies in the pictures. Think about which ones increase the pressure exerted on the support and which ones decrease it, and place them in the appropriate place.

V. Lesson summary.

(slide 18)

Questions:

What physical quantity is called pressure?
What you need to know to find pressure; how it is designated; formula for calculation; units of pressure?
In what ways can you increase or decrease blood pressure?
In what cases does the pressure need to be increased? decrease?
Match:

Homework: § 33, 34

Bibliography. Electronic publications.

Educational electronic publication “Interactive physics course for grades 7-11”, “Physicon”, 2004.
“Open Physics 1.1”, Physikon LLC, 1996-2001, edited by MIPT professor S.M. Cosella.
“Library of electronic visual aids. Physics 7-11 grades", State Institution RC EMTO, "Cyril and Methodius", 2003.
“Physics 7th grade”, publishing house “Drofa”, 2001.

Municipal educational institution "Secondary school in the village of Stepnoe"

Lesson on learning new material, grade 7

Physics teacher Elena Aleksandrovna Tsupenko

CRASSWORD
In previous lessons we talked a lot about the physical quantity that causes changes in speed. What is this quantity called? This is number 4 in the crossword puzzle. We know that there are several types of forces.
No. 8 What is the name of the force with which knowledge attracts all bodies?
What does it depend on? How does it depend?
No. 7 (A demonstrative experiment is being carried out, a load on a spring).
What is the force generated in a spring called? Why is the load at rest?
No. 3 What is the name of the force acting from the load on the spring? What is body weight?
No. 5 (We carry out an experiment: a block, a dynamometer). What force is generated when one body moves along the surface of another? What is the cause of friction? What types of friction do you know?
What types of friction do you know?
No. 1 A device is used to measure force. What is it called?
No. 6 What is the unit of force called?
No. 2 What characterizes the action of force? One of its characteristics is number 2.
Now let's name the topic of our lesson. Vertically in the crossword puzzle.
Open your notebooks and write down the topic of the lesson.

Crassword

study the pressure of solids;
in what units is pressure measured?
find out ways to change pressure in everyday life and technology;
explore ways to increase and decrease pressure;
generalize knowledge about pressure, consolidate the studied material;
test and consolidate acquired knowledge.

The pressure depends on the value of the force that acts on the surface.

The greater the force, the greater the pressure

force

pressure

square

The unit of pressure is the pressure produced by a force of 1 N acting on a surface with an area of 1 m 2 perpendicular to this surface

The unit of pressure is newton per square meter, called Pascal.

M 2

DERIVATIVE UNITS:

1 kPa = 1000 Pa;
1 MPa = 1000,000 Pa;
1 hPa = 100 Pa;
1 Pa = 0.001 kPa;
1 Pa= 0.01 hPa;
1 Pa= 0.000001 MPa.

animal claw

INCREASING PRESSURE IN NATURE

Crocodile's teeth

INCREASING PRESSURE IN NATURE

Bird beak

INCREASING PRESSURE

Needles in medicine

Reducing pressure

Increase in pressure

Building foundation

Airplane landing gear

Wide car tires

Caterpillars of all-terrain vehicles, tractors

Skis

Washers for nuts

Sleepers for rails

Axe

Nails, buttons

Needles

Teeth, claws,

animal beaks

Thorns,

plant spines

wasp sting

APPROXIMATE PRESSURE VALUES, FOUND IN TECHNOLOGY AND EVERYDAY LIFE

PHYSICAL PAUSE.

Before we begin solving problems, we will conduct “Gymnastics for the eyes.”
Close your eyes and then open them. Repeat 5 times.
Make circular movements with your eyes: left - up - right - down - right - up - left - down. Repeat 10 times.
Extend your hand forward. Follow your fingernail with your gaze, slowly bringing it closer to your nose, and then slowly move it back. Repeat 5 times.
Look out the window into the distance for 1 minute.

Examination

1. In what units is pressure measured?
A.N.B.Pa. V. m2.
2.The...area of the support, the...the pressure produced by the same force on this support?
A.more; less. B. more; more. V. less; less.
3. The pressure of a body on the surface depends...
A. on the modulus of force and the surface area perpendicular to which it acts;
B. depends on the modulus of the force and does not depend on the surface area on which the force acts;
B. surface area perpendicular to which the force acts.
4. Express the pressure of 10 kPa in Pa?
A.10000Pa. B.100Pa. V.1000Pa.
5. The quantity equal to the ratio of the force acting perpendicular to the surface to the area of this surface is called...
A.by force of pressure. B. pressure. B. body weight.
6. A machine weighing 12000 N has a support area of 2.5 m2. Determine the pressure of the machine on the foundation?
A) 48Pa. B) 25000 Pa. B) 4800 Pa.
7. How will the pressure on the table change if you place it on its edge?
A) will not change. B) will decrease. B) will increase.
8 A box weighing 960 N exerts a pressure of 5 kPa on the support. What is the support area of the box?
A) 0.192 m.2 B) 19.2 m.2. B) 1.92 m.2

1.A 2.A 3.A 4.A 5.B 6.B 7.B 8.A

0 errors – 5
1-2 mistakes – 4
3-4 mistakes – 3
5-6 errors – 2

Solution:

Given:

F = 500 N

S= 2 m 2

Answer: 250 Pa

Solution:

0.03 m 2

Given:

m = 45 kg

S= 300 cm 2

§ 33; § 34 Ex.12 (1,2,3,4).
*Write an essay “Man and Pressure”

A.V. Peryshkin. Physics textbook 7th grade.
A.V. Peryshkin. Collection of problems in physics grades 7-9.
Maron A.E., E.A Maron Didactic material 7th grade.
IN AND. Lukashik Collection of problems in physics grades 7-9.

Pressure.

Ways to reduce and increase pressure.

Suturina Vera Stepanovna

Physics teacher

What quantities does pressure depend on?

pressure =

From the magnitude of the force acting perpendicular to the surface (F)
From surface area (S)

How to reduce blood pressure?

1) reduce F

2) increase S

Increase F
Decrease S

Questions for consolidation

Do you need wide tracks to reduce or increase tractor ground pressure?

(for decreasing)

2. In order for the soil to withstand the pressure of the building, what needs to be done?

(increase the area of the lower part of the foundation)

3. How do the tire sizes of trucks, cars, and airplanes compare?

4. Give examples of cutting and piercing devices in nature and their connection with the pressure of solid bodies?

The teeth of predatory animals have a pointed shape towards the top, unlike the structure of teeth in humans and herbivores, they do not have a splitting platform. Predators, being in natural living conditions, eat only when they catch their prey. Sometimes this happens once every few days. In this regard, there is a need to slow down the digestion of food. The larger the pieces of food, the longer they take to digest. Therefore, they do not chew food, but chew it and swallow it in pieces. S 2 S 1" width="640"

Try tearing the grass with your hands. You may still succeed, but a piece of meat...

The mosquito sting is cut off at the end like a medical syringe and is placed in a case made of lips.

At bite female mosquito creates a sting pressure at 1 million kg/sq.cm or 100,000 atmospheres. When biting, a mosquito develops a specific pressure of up to I billion kg/cm2? Comparison with a 16 kg kettlebell with a 4 cm base 2 and giving a specific pressure of only 4 kg/cm 2 , shows how great the “mosquito power” is.

Answer the questions:

1. In which of the cases presented in the figure (bricks), the pressure will be the greatest ( I); smallest ( II)?

2) Indicate in which cases shown in the figure the pressures on the surface are equal.

The thickness of the ice is such that the ice can withstand a pressure of 90 kPa. Will a tractor weighing 5.4 tons pass on this ice if it rests on tracks with a total area of 1.5 m2?

2. Containers with a total weight of 5.5 tons were loaded onto a four-axle railway platform. How much did the pressure of the platform on the rails increase if the contact area between the wheel and the rail was 0.5 cm2?

§ 34, exercise 13 (1), task 6 (1).

What determines the result of a force acting on a body? Elastic force F control; Gravity F heavy; Body weight P; Friction force Ftr. What types of forces do you know? What is strength? What is strength? Force is a measure of the interaction of bodies. The result of a force acting on a body depends on its modulus, direction, and point of application.

Elastic forces arise during deformation; occur during deformation; two bodies at the same time; two bodies at the same time; perpendicular to the surface; perpendicular to the surface; opposite to displacement; opposite to displacement; at small deformations, Hooke's law F control = -k x is satisfied; at small deformations, Hooke's law F control = -k x is satisfied

Gravity The force with which the Earth attracts a body towards itself. The force with which the Earth attracts a body towards itself. Formula for finding the force of gravity Formula for finding the force of gravity Ft = mg. Ft = mg. Directed radially towards the center of the Earth; Directed radially towards the center of the Earth; Refers to gravitational forces Relates to gravitational forces

The unit of pressure is taken to be the pressure produced by a force of 1 N acting on a surface of 1 m 2 perpendicular to this surface 1 Pa1 N M2M2 Unit of measurement of pressure Blaise Pascal () French mathematician, physicist, writer and philosopher.

Derived units: 1 kPa = 1000 Pa; 1 kPa = 1000 Pa; 1 MPa = Pa; 1 MPa = Pa; 1 hPa = 100 Pa; 1 hPa = 100 Pa; 1 Pa = 0.001 kPa; 1 Pa = 0.001 kPa; 1 Pa= 0.01 hPa; 1 Pa= 0.01 hPa; 1 Pa= 0, MPa. 1 Pa= 0, MPa.

Reducing pressure Increasing pressure Building foundation Airplane chassis Wide car tires Caterpillars of all-terrain vehicles, tractors Skis Washers for nuts Sleepers for rails Ax Knife Nails, buttons Needles Teeth, claws, beaks of animals Spikes, thorns of plants Wasp sting

3. The pressure of a body on a surface depends... A. on the modulus of force and the surface area perpendicular to which it acts; B. depends on the modulus of the force and does not depend on the surface area on which the force acts; B. surface area perpendicular to which the force acts. 4. Express the pressure of 10 kPa in Pa? A.10000Pa. B.100Pa. V.1000Pa. 5. The value equal to the ratio of the force acting perpendicular to the surface to the area of this surface is called... A.pressure force. B. pressure. B. body weight.