Air humidity, 28

Long-term plan unit: 

School:

Date:

Teacher name:

Grade: 10 Physics

Number present:

absent:

Theme of the lesson

Air humidity, dew point

Learning objectives(s) that this lesson is contributing to

10.2.4.1 – to define relative air humidity.

Lesson objectives

-          to know and understand what absolute and relative humidity is;

-          to know and understand what is meant by dew point;

-          to know and understand the principle of device operation for measuring air humidity;

-          to be able to determine the relative humidity.

Evaluation criteria

A student has achieved a learning goal if ...

-           gives the definition of absolute and relative humidity, dew point;

-          describes the principle of device operation for measuring air humidity;

-          determines the relative humidity.

Language Objectives

Subject-Specific Vocabulary and Terminology:

Absolute humidity, relative humidity, air volume, water vapor density temperature

Useful Sets of Phrases for Dialogue and Writing:

There is a special table in which saturated water vapor density is given for each temperature value and pressure.

Previous learning

Students are familiar with the atmosphere of the Earth, which they have studied in 7 grade, and they knew that it consists of a mixture of different gases, besides that there is water vapor in the air.

Course of the lesson

Planned timings

Planned activities at the lesson

Resources

Beginning

5 min

(T, W) Organizational moment

Task: continue the sentences.

Aim: check knowledge of students about topic

Teacher’s action: The teacher reads the unfinished sentence, which should be completed so that the correct statement is obtained (the answer should be written by students).

Student’s action: students listen to the teacher carefully and write the answers in the copy book, then students check each other.

Feedback: teacher-student, student-student

Define the topic of the lesson and lesson’s objectives.

App 1

Middle

1-2 min

5 min

3 min

10 min

14 min

Motivation for learning activities

The atmosphere always contains water vapor, as a result of the evaporation of water from the free surfaces of open water reservoir. The content of water vapor in the air significantly affects the livelihoods of living organisms (plants, animals, humans), the development of flora and fauna on Earth, the climate of the Earth, the corrosion processes in the details of technical mechanisms, devices, machines. Humidity depends on many factors - the physical state of the atmosphere, temperature, proximity of the seas and oceans and other water bodies. So, the measurement of humidity is one of the necessary and important skills both for industrial purposes and in everyday life.   

Task: watch the video and study new topic

Aim: to know and understand what absolute and relative humidity is; to know and understand what is meant by dew point;

Task description:

Questions:

1.      What is air humidity? (Air humidity is the value for the amount of water vapor in the atmosphere).

2.       How can we determine the humidity?

3.       What do we call relative humidity?

4.       What is saturated and unsaturated vapor?

5.       What is dew point?

Teacher’s action: show the video, stop it during translation and ask students questions about new material, organize the students’ work of making notes, ask some questions, and check student’s work.

Student’s action: work, watch the video carefully, answer for the questions, can ask some questions and discuss the problem.

Feedback: teacher-student

Task: determine absolute and relative humidity

Aim: to know and understand what absolute and relative humidity is.

Teacher’s action: organize the students’ individual work.

Student’s action: students work individually,using book, fill the table.

Feedback: teacher-student

Task: Group work.

Aim: to know and understand the principle of device operation for measuring air humidity.

Teacher’s action: provide the additional material, organize student’s work.

Student’s action: work with book. Students read the principle of operation of the condensation hygrometer and psychrometer, discuss in groups, draw up a flipchart and prepare to present to the class. Groups evaluate work of each other.

Group I: hygrometer

Group II: psychrometer

Practical work

Aim: determines the relative humidity.

According to the value of relative humidity, we can judge the state of the air around us.  And now we are going to measure humidity of our class room, but we do not have a special device. How do you think we can measure the humidity of the air, if we only have a thermometer?

Equipment: laboratory thermometer, cuvette with water, a piece of bandage.

Procedure:

1.   Measure the temperature of the air in the classroom using thermometer and write it down in a copybook.

2.   Moisten a piece of dressing and wrap a thermometer in it. Watch the temperature drop. Once the temperature has settled, record the reading of the thermometer.

3.   Find the temperature difference between dry and wet thermometer and, using psychrometric table, determine the relative humidity in the class.

Safety rules:

Remember that a glass thermometer must be handled carefully. After completing the task, do not forget to put the thermometer in the case.

Conclusion.

For a person, a comfortable level of humidity ranges from 40 to 60%. When central heating is working, the humidity in the rooms drops to 25%.

What do you think is the danger of dry air?

(Discomfort, fatigue, illness. Dry air prevents the ingress of oxygen into the circulatory system. Symptoms of insufficient oxygen consumption - exhaustion, poor concentration, fatigue.

• Increases susceptibility to infection. The self-cleaning ability of the bronchial tube is reduced due to the inhaled dry air, resulting in an increased susceptibility to infections and various respiratory diseases.

• Dry skin. The lack of moisture in the air accelerates the evaporation of water from the skin. During the day, the skin loses about 1/2 liter of water, and in winter - up to a liter. It becomes dry, rough and begins to peel off, looks old and ugly.

• Dry eyes. Humid air also causes additional irritation to contact lens wearers.

• Dust. Moisture "binds" dust. Dry air and, in addition, the heat emitted by heaters, on the contrary, lead to the fact that dust flies throughout the room. It is especially contraindicated for asthmatics and allergies.

• Plants die. Their leaves turn brown, with shriveled tips, buds and flowers dry out and fall off.

• Upset musical instruments. Frustrated musical instruments are also the result of insufficient air humidity.

• Cracks in wood objects. If the room is constantly dry air, furniture and other wooden objects gradually lose their original appearance. They begin to shrink and cracks appear over time.)

https://www.youtube.com/watch?v=PNsF5PzNVJo

App 2

End

1 min

(W) Students’ Reflection

Continue the sentence:

Today I’ve learned at the lesson ...

Now I can …

It was interesting …

Home task:

Differentiation – how do you plan to give more support? How do you plan to challenge the more able learners?

Assessment – how are you planning to check students’ learning?

Health and safety regulations

Give problem questions

Student-student assessment

Student-teacher assessment

Rules of Technics of Safety at chemistry room

Reflection

Were the lesson objectives/learning objectives realistic? Did all learners achieve the LO?

If not, why?

Did my planned differentiation work well?

Did I stick to timings?

What changes did I make from my plan and why?

Use the space below to reflect on your lesson. Answer the most relevant questions from the box on the left about your lesson. 

Summary evaluation

What two things went really well (consider both teaching and learning)?

1:

2:

What two things would have improved the lesson (consider both teaching and learning)?

1:

2:

What have I learned from this lesson about the class or achievements/difficulties of individuals that will inform my next lesson?