Teaching design of the first lesson "The Secret of Thermometer"

Teaching objectives:

1. By guiding students to learn the structure and principle of thermometer, let them know that all liquids have the property of expanding when heated and contracting when cooled.

2. Instruct students to learn how to do the experiment of liquid expanding with heat and contracting with cold, and cultivate students' experimental ability and preliminary analysis ability.

3. Learn to cooperate, communicate and reflect.

Teaching preparation:

1, one simulated thermometer for soy sauce alcohol and two sinks.

2. Thermometers for demonstration 1, and thermometers for each experimental group 1.

3. Students collect all kinds of thermometer data before class.

Teaching process:

First, the introduction of new courses.

1, show me an oral liquid of Shuanghuanglian, intubate and talk: What do you observe?

Students observe and answer.

Why is this happening? Today we are going to learn the science of thermometer.

Second, learn new lessons.

1. Understand that water and other liquids expand when heated and contract when cooled.

(1) Question: Show analog thermometer and demonstration thermometer, and compare their structural similarities. What happens to the liquid column when it is placed in hot water and cold water respectively?

(2) Students are divided into groups to carry out experiments: analog thermometers are put into two water tanks filled with hot water and cold water respectively, and the changes of liquid columns are observed.

(3) Discussion: The water in the bottle has neither increased nor decreased, but the liquid column has risen and fallen. What's going on here?

(4) Students discuss and report.

(5) Summary: The heated volume of water will expand, so the liquid column will rise; The volume of water shrinks after cooling, so the liquid column drops. We call this property of water "the property that water expands with heat and contracts with cold".

(6) Question: Do other liquids have this property? Can students design an experiment to prove it?

(7) Students experiment, discuss and report.

(8) Teacher-student summary: All liquids have the property of expanding with heat and contracting with cold. Thermometers are made according to the characteristics of liquid expanding when heated and contracting when cooled.

2. Guide students to understand the invention of centigrade thermometer.

(1) Students look at the reading part of the textbook.

(2) Question: Who made the temperature measurement standard of Celsius? How is the calibration standard stipulated?

(3) Students discuss and report.