1. In the process of playing the compass, students can find that the compass is an instrument used to determine the direction. Made of magnet, it has the property of indicating north and south, and know the purpose and usage of compass.
2. Guide students to make simple compasses, and cultivate students' experimental ability and hands-on production ability.
3. Introduce the history of compass and educate students in patriotism.
Teaching preparation
1, compass, magnet, cotton thread, nail, thin foam plastic board, water, sink, application chart or slide of compass.
2. Each group has 1 magnetic experiment box (including compass, various magnets, thimbles, etc.). ).
3. Scissors, blow-molded paper, steel needle, thread, glue, scotch tape, etc.
Teaching process design
course content
Teacher-student activities
comment
First, the introduction of new courses.
Second, learn new lessons.
1. Introduce the history of the compass.
2. Study what the compass is made of.
3. Guide students to know that magnets can indicate north and south.
4. Guide students to know the purpose of the compass.
5. Instruct students to make compasses.
Dialogue: Compass is one of the four great inventions in ancient China. Although it is a small matter, it is of great use. Such as navigation, aviation, surveying, exploration, etc. , are inseparable from the compass. So what is the compass made of? Why does it have such a great ability? Today, let's be a little scientist and explore the secrets of the compass. (blackboard writing topic)
As early as more than two thousand years ago, our ancestors discovered that a stone on the mountain had the magical property of absorbing iron, and found that a long stone could refer to the north and south. They call this kind of stone a magnet. Ancient craftsmen polished and chiseled magnets into spoon shapes, put them on a mirror-smooth chassis made of bronze, and then cast directional carvings. When the magnetic spoon stops rotating on the chassis, the handle of the spoon guides and the mouth of the spoon points north. This is the earliest musical instrument in the world invented by our ancestors, called Sina. Sina's "thinking" means "ambition".
Later, the ancients made an ancient compass based on Sina. The compass at this time is very similar to the compass used now. It has a magnetic needle pointing in the direction and a dial showing the direction. Installing a compass on a ship can guide people to sail. About 800 years ago, the compass invented by our country spread to Africa and Europe, and there were only instruments to indicate the direction in the world. This is a great contribution of the people of China. This has greatly promoted the exchanges among countries in the world and the development of science, culture and economy. We are very proud of the contribution made by the ancient working people of our motherland to the development of world science and technology.
(1) Question: What is the compass made of?
(1) Students observe the experiment on page 36 of the textbook.
(3) Report the observation and experimental results.
(4) Teacher-student summary: The compass can absorb iron, indicating that it is made of magnets.
(1) Question: A compass can indicate north and south, so can a magnet indicate north and south?
(2) Students' experiments. With magnets of different shapes, we can draw a conclusion after repeated experiments. If the suspension method is used, the suspension line should be shorter, and then observe when the magnet stops; If the support method is adopted, the magnet should be able to rotate flexibly on the bracket and observe after stopping; If you float with the water, you can put a piece of foam in the sink, put the magnet on the foam, and then observe the direction indicated by the magnet when it stops rotating.
(3) Students report the experimental results.
(4) Teacher-student summary: Experiments show that magnets of different shapes and sizes have the property of indicating north and south. A magnet has two poles. One end of the guide rail is called the South Pole, which is indicated by "S". The end pointing to the north is called the North Pole and is represented by "n".
(1) Discussion: Compasses have many uses. Do you know where it can be used?
(2) Students observe the illustrations on page 38 of the textbook and discuss O-
(3) Teacher-student summary: Compass is widely used, and it needs to point out the direction in many aspects such as geological exploration, field investigation, military deployment, commanding operations, mountain climbing direction finding, aviation navigation, urban and rural planning and design.
Talk: Now, we already know the structure, principle and usage of the compass, as well as its history and use. Let's use this knowledge to make a simple and dexterous compass by ourselves.
(1) Explain the production method: ① See the left picture on page 38 of the textbook for the required materials. ② Magnetized steel needle. In order to make the steel needle have strong magnetism, a magnet should be used to rub the steel needle in the same direction for 20-30 times. (3) The magnetic needle can rotate flexibly and can be made by floating water.
A simple compass. (Hanging method or thimble method can also be used) ④ Stick the words "East", "South", "West" and "North" on the edge of the sink evenly clockwise, with the words facing outwards. Then turn the water tank (dial) to stand still, and observe the magnetic needle to see which end of the magnetic needle is oriented and which end points to the north. At this point, a water floating compass is ready. When in use, after the magnetic needle stops rotating, gently rotate the dial so that the scale in the south direction is opposite to the south pole of the magnetic needle, and other directions can be recognized.
(2) Students make it by hand, and teachers tour to guide it.
(3) Problems existing in the process of making teacher's summary and improvement methods.
Feeling after class
Compass has a long history, and students have seen or used this kind of equipment in their daily lives, so it is easier to take this course and students can operate it skillfully.