"Thermal Expansion and Cold Contraction" Changes in Matter PPT Courseware

Description

"Thermal Expansion and Cold Contraction" Changes in Matter PPT Courseware

In 1593, Galileo invented the first air thermometer.

In 1632, the French chemist Rey improved Galileo's thermometer and invented the liquid thermometer.

What properties of air and liquid do these two thermometers exploit? Let's study it.

Homemade "liquid thermometer"

When describing experimental phenomena, we need to make it clear what we saw before, during, and after the experiment, as well as what the experimental conditions were.

When a liquid is heated, its volume expands; when it is cooled, its volume shrinks.

This is the thermal expansion and contraction properties of liquids.

The principles of commonly used thermometers:

It is made based on the principle of thermal expansion and contraction of liquids such as mercury, kerosene, and alcohol.

Does air also have the property of expanding with heat and contracting with cold?

important hint

1. When designing an experiment, what container should the air be placed in?

2. How can we see the expansion and contraction of air?

The composition of alcohol lamp flame

The outermost flame has the highest temperature and is called the outer flame.

The second layer of flame has a lower temperature and is called the inner flame.

The innermost flame has the lowest temperature and is called the flame core.

Use the outer flame of an alcohol lamp when heating objects.

Rules for using alcohol flame

First check the wick

Before using an alcohol lamp, check whether the wick is intact. If the top is uneven or burnt, it needs to be cut flat.

Second, add alcohol

When pouring alcohol into the lamp kettle, use a small funnel as a guide. It is absolutely forbidden to add alcohol to a burning alcohol lamp.

The amount of alcohol in the lamp kettle should not exceed 2/3 of the lamp kettle and should not be less than 1/4 of the lamp kettle.

Third, light the alcohol lamp

Only burning matches or wooden sticks are allowed to light alcohol lamps. It is prohibited to use a burning alcohol lamp to light another alcohol lamp. Because the overflowing alcohol from the side alcohol lamp can easily cause a fire when ignited.

Fourth: Extinguish the alcohol lamp and handle accidents

1. Extinguish the alcohol lamp

The fire must be covered with a lamp cap and cannot be blown with the mouth. After extinguishing, the lamp cap must be opened again and then buckled up so that the atmospheric pressure inside and outside the lamp cap is the same, making it easy to open the next time it is used (be sure to cover the lamp cap when not in use to prevent alcohol from evaporating).

2. Accident handling

If the alcohol lamp is knocked over and the alcohol spills and burns on the table, you should deal with it calmly and quickly cover it with a wet rag or sprinkle sand.

Do it

Solids also have the property of expansion with heat and contraction with cold.

Talk about it

What experimental phenomena did you see?

What does it tell us?

Solids, liquids, and gases all have the property of expanding with heat and contracting with cold.

Talk about it

The phenomenon of thermal expansion and contraction in life.

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For more information about the "Changes of Matter Thermal Expansion and Contraction" PPT courseware, please click on the "Changes of Matter PPT Thermal Expansion and Contraction PPT" tab.

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"Does Metal Expand and Contract with Heat?" Hot PPT Download Part One: Experimental Research Take a copper ball as an example to observe whether metal has the property of thermal expansion and contraction. Observe the thermal expansion and contraction of the copper ball. Experiment name: Does the copper ball expand and contract with heat? Experimental equipment: Alcohol lamp, copper ball thermal expansion and contraction...

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"Does Metal Expand and Contract with Heat?" Thermal PPT Part 1: Observe the thermal expansion and contraction of copper balls. Do experiments to observe the thermal expansion and contraction of copper balls. 1. Pay attention to the safety of using alcohol lamp; 2. Do not touch the copper ball. The heated copper ball will burn the skin. Describe the experimental process and what you saw...

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Update Time: 2024-10-01

This template belongs to science courseware People's Education Press Fifth Grade Science Volume 2 industry PPT template

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