"Drilling Wood to Make Fire" PPT

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"Drilling Wood to Make Fire" PPT

Part One: Drilling Wood to Make Fire

Students, do you know how ancient people used fire? Do you know how people ate before they knew how to use fire?

What is the significance of humans starting to use fire?

Fire is the earliest natural force utilized by human beings. The use of fire heralded the end of human history of eating hair and drinking blood, and was a big step forward in the journey of human civilization.

Drilling wood to make fire

Wood itself has no fire, so where does fire come from?

The two pieces of wood rub against each other, generating heat. The heat generated has no time to diffuse into the air. It accumulates more and more, and the temperature gradually rises. Finally, sparks are generated, causing the wood to burn.

Classical style drilling wood to make fire

First, find the right wood to make the drill board. Dry poplar, willow, etc. will be a good choice because their texture is soft. Then find a suitable branch to make a drill bit, which is relatively hard. The conditions are not as harsh as drilling boards. Then, drill a small inverted "V"-shaped groove on the edge of the drill plate, as shown in the picture.

Finally, put a flammable tinder or dead leaf under the drilling board, and then drill with both hands until a fire comes out.

Two-person classic wood drilling method

One person uses a grooved wooden cover to fix the drill shaft to the drill board, and the other person wraps a rope or rattan with high friction around the drill shaft several times, and then pulls it back and forth quickly. The efficiency of this kind of two-person cooperation is much stronger than the first one.

Part Two: Content Exploration

Check out the information and explore further:

(1) In addition to being converted into thermal energy, what other energy can mechanical energy be converted into?

(2) Why can mechanical energy be converted into various other energies?

What benefits does energy conversion bring us?

Convert mechanical energy into electrical energy

Conversion of mechanical energy into thermal energy

Part Three: Combustion Conditions

Combustion requires two conditions:

One is enough oxygen;

The second is the temperature that reaches the ignition point of combustibles.

In ancient times, humans have mastered the method of drilling wood to make fire. The reason why drilling wood can make fire can be explained by the following three sentences:

A: The internal energy of wood increases and the temperature rises

B: Reach the ignition point of the wood and make the wood burn.

C: Work is done by overcoming friction when drilling wood.

The correct order of these three sentences is ( )

A． A, B, C B. C, A, B C. B, C, A D. A, C and B

Keywords: Qingdao version fifth grade science PPT courseware for the second volume free download, Drilling wood to make fire PPT download, .PPT format;

For more information about the "Drilling Wood to Make Fire" PPT courseware, please click on the "Drilling Wood to Make Fire" ppt tag.

"Drilling Wood to Make Fire" PPT courseware download:

Download the PPT courseware of "Drilling Wood to Make Fire" Part One: Introduction of new lessons According to records, all kinds of food eaten by ancient people were raw. Therefore, people's life span is relatively short, usually around the age of twenty, and a special phenomenon occurs by chance. That..

"Drilling Wood to Make Fire" PPT download:

The first part of PPT download content of "Drilling Wood to Make Fire": The Legend of Drilling Wood to Make Fire. The earliest primitive people did not know how to use fire. They ate everything raw. Eating raw plant fruits was not just the wild beasts they had beaten. They were also eaten alive, with hair and blood on them. Later,...

"Drilling Wood to Make Fire" PPT courseware:

"Drilling Wood to Make Fire" PPT Courseware Part One: The Definition of Drilling Wood to Make Fire There is no fire in wood itself, so where does fire come from? The two pieces of wood rub against each other and generate heat. The generated heat has no time to diffuse into the air. It accumulates more and more, and the temperature gradually rises...

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Update Time: 2024-11-22

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