lesson plan (1)

Long term plan section:

 Statics and hydrostatics

School:

Date:

Name of the teacher:

Grade: 10

missings':

The theme of the lesson

Centerofgravity. Types of balance.

Learning objectives that are achieved in this lesson

10.1.3.1- determines the center of gravity of an absolutely rigid body and explains the different types of equilibrium.

Lessonobjectives

·         To determine the balance of the body, to find out the conditions under which the body is in equilibrium.

·         To introduce different types of balance.

·         Learn to determine the center of gravity of the body.

·         Consider the practical application and consideration of the equilibrium conditions of bodies in different areas of life.

Successcriteria

The student has achieved the learning objective if:

·         Describes how the position of the center of gravity of a planar figure is determined;

·         Formulates the position of the center of gravity of a plane figure through an experiment;

·         Indicates the reasons for the balance of bodies;

·         Provides examples of the application and consideration of the equilibrium conditions of bodies in different areas of life.

Languagegoals

Absolutely solid body, center of gravity, equilibrium, types of equilibrium (stable, unstable, indifferent), statics.

Students can describe an experiment to determine the center of gravity of a flat figure, knows the conditions under which the body is in equilibrium, can consider the practical application and consideration of the equilibrium conditions of bodies in different areas of life.

Instillingvalues

Expanding the horizons of students, the development of functional literacy, responsibility and independence in their learning.

Thelesson

Planned stages of the lesson

Planned activities at the lesson

Resources

The beginning of the lesson

0-2 min

2-4 min

1.Organizational point: Psychological mood, the message of the lesson theme and goals)

Type of lesson: lesson of learning new material

PROBLEMATIC ISSUE

So, what will be the subject of our conversation today? What is the topic of the lesson?                                      Slide-1,2

Questions of balance are of interest to builders, machine builders, climbers, circus artists and many others.

Presentation

The middle of the lesson

       4 - 14 min

14 -26 min.

26-32 min.

         32-36 min.

2.Explanation of the new topic

Form: school

Reception: problem question

What is the center of gravity? Until now, it was said about the force of gravity as one force acting on the body as a whole. But in fact, gravity is composed of many forces applied to each part of the body.                                  Slide 3

The point of application of the resultant gravity acting on individual parts of the body is called the center of gravity of the body.

How can you find the center of gravity in different bodies?

If the body is uniform and has the correct shape, then everything is simple. In homogeneous bodies of regular shape the center of gravity coincides with its geometric center. For example, the center of gravity of the ball lies in its geometric center, a rectangular parallelepiped — at the intersection of diagonals, and a triangle — at the intersection of its medians.

In some cases, the center of gravity may be outside the body. For example, the ring it lies on the intersection of its diameters.  

Slide 4

At any position of the body its center of gravity is located at the same point.                                                      Slide 5

From the position of the center of gravity depends on the equilibrium condition of the body.                                                                                

If the vertical, drawn through the center of gravity of the body, crosses the area of its support, the body will be in equilibrium. Ifnotcrosses, thenbodyfalls.                                                      Slide 6

An interesting example of the balance of a body on a support is the leaning tower in the Italian city of Pisa, which, according to legend, Galileo used to study the laws of free fall of bodies. The tower has the shape of a cylinder with a height of 55 m and a radius of 7 m. The top of the tower is rejected from the vertical by 4.5 m.

A vertical line drawn through the center of mass of the tower crosses the base approximately 2.3 m from its center. Thus, the tower is in equilibrium. The balance will be broken and the tower will fall when the deviation of its top from the vertical reaches 14 m. Apparently, this will happen very soon. Slide 7

If the body is at rest, then they say that this body is in balance. The section of mechanics in which the conditions of equilibrium of absolutely rigid bodies are studied is called static.

  An absolutely solid body is a body, the distance between two points of which during interaction with other bodies remains unchanged (the deformation of the body can be neglected).

                                                                                              Slide 8

If a solid is in equilibrium, then the geometric sum of the external forces applied to it is zero.

When a solid is in equilibrium, the sum of the moments of all external forces acting on it with respect to any axis is zero. Slide 9

In practice, an important role is played not only by the fulfillment of the condition of body equilibrium, but also by the qualitative characteristic of equilibrium, called stability.

There are 3 types of equilibrium:

Sustainable Unsustainable Indifferent. Slide 10

3. Perform laboratory work.

"Determination of the center of gravity of a flat plate"

                                                                                       Slide 11,12

The order of performance

1. Clamp the stopper in a horizontal position in the leg of the tripod.

2. Using a pin, which is inserted into the cork, hang the plate and plumb line.

3. With a sharply sharpened pencil, mark the plumb line on the lower and upper edges of the plate.

4. After removing the plate, draw a line on it connecting the marked points.

5. Repeat the experiment by hanging the plate at another point.

4. Practical application of Slide-13-16

5. Thesolutionofqualityproblems

Purpose: Identification of the quality and level of mastery of knowledge and, if necessary, the correction of misunderstanding (the class is divided into groups - each group has a task-defense.

1. With what purpose do circus artists hold heavy poles while walking on a rope?

2.Why does a person carrying a heavy load on his back lean forward?

3. Why not stand up from a chair, if you do not tilt the body forward?

4.Why the crane does not tip over towards the lifted load? Why does the crane not tilt in the direction of the counterweight without a load?

5. Why cars and bicycles, etc. Is it better to put the brakes on the rear wheels and not on the front wheels?

6.Why is a truck loaded with hay easier to roll over than the same truck loaded with snow?

https://www.youtube.com/watch?v=ajTyhbvMEAg

The end of the lesson

36-40 min.

6. Reflexion

Purpose: Mobilization of students to reflect on their behavior (motivation, ways of activity, communication).

Continue the offer:

Now I know…

And I can ...

It would be interesting to learn more ...

7. Homework. To make a toy "Egg-tumbler", to make a design of forks, etc., the definition of the center of gravity of the shape of an arbitrary shape.

8. The result of the lesson

Objective: To analyze and evaluate the success of achieving the goal and to outline the prospects for future work.

Differentiation - how do you plan to provide more support? What tasks do you plan to set for more capable students?

Grading - How do you plan to check students' level of learning?

Healthandsafety

All students will be able to formulate the conditions of equilibrium, experimentally determine the center of gravity of a flat figure. Consider the practical application and consideration of the equilibrium conditions of bodies in different areas of life.

Some students will be able to: explain different kinds of balance.

Advanced students are aware of the different

methods for determining the center of gravity of the body..

·         Cross-checking.

·         Self-test.

·         Oralsurvey

Instruction on TB during laboratory work in the classroom.