"Controlling the Speed ​​of Iron Rusting" Changes in Matter PPT Download

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"Controlling the Speed ​​of Iron Rusting" Changes in Matter PPT Download

Part One: Exploring New Knowledge

scientific symposium

In the section "Iron rusts", we hypothesized that iron rusting is related to water and air, and designed comparative experiments to verify it. In this section, we will analyze the experimental results to verify whether our hypothesis is correct.

1. Explore the topic: The reason why iron rusts.

Research question: Is iron rust related to air?

Our hypothesis: The rust of iron is related to the air, because we found that the parts of the iron nails exposed to the air have rusted, but the parts nailed in the wooden boards have not rusted.

Experimental materials: 3 plates, 3 nails, water, vegetable oil

experimental method:

1. Use plates of the same size, fill two of them with water and vegetable oil respectively.

2. Place one iron nail in an empty plate in contact with the air, another iron nail completely immersed in vegetable oil, and another iron nail half placed in water.

3. Observe and record once a day.

What is the result of the experiment?

The empty plate rusted very slowly, the water plate rusted very quickly, and the amount of rust was also large, and the vegetable oil plate did not rust.

Think about the reasons why:

The iron nail can contact the air in the empty plate, the iron nail can partially contact the water in the water plate, and the iron nail immersed in the vegetable oil plate cannot contact the air and water. It can be seen from the experiment record sheet that the iron nail is in Empty plates will rust when exposed to air, but the rust rate is very slow. Iron nails in a water plate will rust quickly, and the amount of rust is also large. The phenomenon is very obvious. Iron nails in a rapeseed plate will rust. No rust.

What is the conclusion of the experiment?

Iron rust is related to water and air.

PPT on controlling the speed of iron rusting, part 2: expansion and extension

Why doesn’t stainless steel rust?

The reason why stainless steel does not rust is because it contains [chromium].

Usually the chromium content must reach 13 to 25% (weight ratio) to change the oxidation of the steel surface.

However, stainless steel is not really free from rust. If you observe it with a microscope, there are actually many small rust spots on its surface. If you look closely, you will find that these spots contain sulfur, and the presence of sulfur element is indispensable in the process of making steel. Avoided.

But how did they start?

Recent research has found that it is not the sulfur atoms that turn into sulfuric acid in water that causes corrosion, but that during the manufacturing and cooling process of stainless steel, the chromium in the steel moves to certain places and partially replaces the manganese in the manganese sulfide. location, which in turn causes the chromium content near that location to become lower.

When the chromium content is less than 13%, stainless steel will rust.

Controlling the speed of iron rusting PPT, part three: summary of this lesson

1. Iron rust is related to water and air.

2. Iron rusts due to the combined action of water and air.

3. These methods can prevent and slow down iron rust

(1) Form an alloy to change the internal structure of iron.

(2) Covering the surface of iron products with a protective layer is a common and important method to prevent iron products from rusting.

(3) Keeping the surface of iron products clean and dry is also a good way to prevent iron products from rusting.

Controlling the Speed ​​of Iron Rusting PPT, Part 4: Exercises in this Lesson

1. Judgment questions

1. The reaction between baking soda and white vinegar is relatively slow, and iron will rust very quickly. ( )

2. The reason why stainless steel does not rust is because it contains chromium. ( )

3. Iron nails rust faster in salt water than in humid or dry environments ( )

4. Although iron rusts, it will not cause much damage. ( )

2. Fill in the blanks

1. Iron rust is a ___________ change that occurs in iron under the combined action of ___________ and ___________.

2. Place two iron nails in the air and on a damp paper towel. The nail placed on _____________ will rust faster.

3. Iron nails _________ rust in a vacuum environment.

4. We hypothesize that iron rust is related to water and air, and design ________ experiments to verify it.

3. Short answer questions

1. Could you please tell me how to deal with washed iron pots and kitchen knives?

Wipe the water dry and place it in a dry place

If not used for a long time: apply a layer of vegetable oil on the surface and seal the bag

2. In life, how do people prevent iron from rusting and slow down the speed of iron rusting? Think about the science behind it.

1. Apply paint to isolate air and moisture

2. Apply grease to isolate air and moisture

3. Electroplating to isolate air and moisture

4. Made of stainless steel. Baking blue: forming a dense oxide protective film on the surface.

Controlling the Speed ​​of Iron Rusting PPT, Part 5: Homework

Share, what kind of experience do you have after studying this course?

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"Controlling the Speed ​​of Iron Rusting" PPT teaching courseware on changes in matter:

"Controlling the Speed ​​of Iron Rusting" PPT teaching courseware on changes in matter Part one: Exploration: Is iron rusting related to air? Experimental conclusion: Iron rusting is the result of the combined action of water and air. What does the speed of iron rusting depend on? The speed of iron rusting and the speed of water...

"Controlling the Speed ​​of Iron Rusting" Changes in Matter PPT:

"Controlling the Speed ​​of Iron Rusting" Material Changes PPT Part One: Scientific Discussion We studied the causes of iron rusting and conducted comparative experiments. Let us share the research results! Research question: Is iron rust related to air? Our hypothesis: Iron...

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Update Time: 2024-10-03

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