"Wood" PPT

"Wood" PPT

Part One: Exploration Questions

Questions to explore:

1. Texture of wood

2. Can it burn?

3. The softness and hardness of wood

4. The ups and downs in the water

5. Can it conduct electricity?

6. Heat conductivity of wood

"Wood" PPT, part 2: experimental exploration

Research Tips

During the experiment you should pay attention to:

1. Pay attention to safety and prevent injuries

2. Work together in groups, observe carefully, study and record at the same time.

3. Pay attention to the usage of the alcohol lamp: Use the external flame of the alcohol lamp (because the outer flame has the highest temperature). When extinguishing the alcohol lamp, cover it with the lamp cap.

"Wood" PPT, the third part: Characteristics of wood

Observe with a magnifying glass - the wood has texture (growth rings)

Burn with alcohol lamp - wood can burn

Carve with a knife - wood can be soft or hard

Put in water - most wood will float

Connecting to a circuit - Dry wood does not conduct electricity, but wet wood conducts electricity

Knowledge expansion: growth rings of wood

There are circles of marks on the cross section of the sawn tree, which are the annual rings of the tree. Counting the rings on the cross section of a big tree can tell how many years the tree has grown.

Plant growth generally forms one annual ring. In the spring and summer, the temperature, moisture and other environmental conditions are relatively good, the plants grow vigorously, the cells are larger, and the annual rings formed are looser and lighter in color; in the autumn and winter, the growth is slow, the annual rings formed are tighter and darker in color.

The growth rings formed on the sunny side of the plant, that is, the south side, are looser, while the growth rings formed on the backside of the plant, that is, the north side, are tighter. Therefore, people can identify the direction from the annual rings of the plant.

"Wood" PPT, part 4: uses of wood

Make furniture (wardrobe, bed, dining table and chairs), build a house (beams, windows, doorways, etc.)

build a bridge

Lay rails as sleepers

decorative materials

Office supplies (desks, chairs)

Entertainment products (chess pieces, slides),

School supplies (pencils, paper products)

Some also have fragrances that can repel insects (such as camphor wood)

Some can make spices. For example, there is a ylang-ylang tree, which is called a "natural perfume tree"

Some can be used as Chinese medicinal materials. like ginkgo tree

It also has extremely high collection value. Such as golden nanmu, rosewood, plow wood

Wood is a natural material

What are natural materials and what are man-made materials?

Natural materials: They grow naturally in nature and are treasures given to mankind by nature. Such as: cotton, wood, bamboo, coal, oil, natural gas, wool, iron ore, etc.

Man-made materials: Also known as synthetic materials, they are materials artificially processed by chemical methods or polymerization of different natural substances. Such as plastic, glass, steel, artificial leather, etc.

"Wood" PPT, Part 5: Expansion

Expand and extend relevant information on disposable chopsticks

Students: After reading the information below, do you still use disposable chopsticks?

Disposable chopsticks were invented by the Japanese. Japan's forest coverage rate is as high as 65%, but they do not cut down the trees on their own land to make disposable chopsticks. They rely entirely on imports. Our country's forest coverage rate is less than 14%, but it is a major exporter of disposable chopsticks. The disposable chopstick industry in northern my country exports 1.5 million cubic meters to Japan and South Korea every year, reducing forest accumulation by 2 million cubic meters.

Relevant experts also told us that a 10-year-old tree can produce 4,000 pairs of chopsticks. In a city like Jinan, more than 100 million pairs of sanitary chopsticks are used a year, which means we "eat" more than 25,000 trees every year. Across the country, there are currently nearly a thousand chopstick manufacturing companies, with an annual output of 30 million boxes of chopsticks (500 pairs per box), consuming 5 million cubic meters of forest resources every year, equivalent to a forest area of ​​15 million square meters, and are "eaten" every day. The forest covers more than 40,000 square meters.

Extracurricular development (homework)

Small survey: How many disposable chopsticks are used in a medium-sized restaurant in a day? How much wood is used in a year? Write an investigation report after the investigation.

Keywords: Qingdao edition fourth grade science PPT courseware free download, wood PPT download, .PPT format;

For more information about the "Wood" PPT courseware, please click on the "Wood ppt" tab.

"Wood" PPT download:

"Wood" PPT Download Part One: Warm Tips According to the content of your own research, determine the appropriate research methods and formulate a reasonable experimental plan. Choose experimental materials and tools. Conduct experimental research according to the plan and keep experimental records. be safe. ..

"Wood" PPT courseware:

"Wood" PPT courseware Part 1 content: Learning objectives: 1. Experience cooperation and communication in observation and experimental activities to explore the characteristics of wood. 2. Know that wood is a natural material and understand its properties and uses. Self-study guidance: Observe the pictures and read the text in textbook 40..