"Little Parachute" PPT courseware

Description

"Little Parachute" PPT courseware

Review Questions to Think About

1. How many parts does a parachute consist of?

2. What are the material requirements for making a parachute?

3. What factors are related to the speed of parachute descent?

4. The principle of parachute landing

What is the principle behind the slow descent of a parachute?

1. The process of falling objects is affected by two forces in opposite directions: gravity and air resistance.

2. Since the air resistance is proportional to the windward area of ​​the object, and the parachute is characterized by its light weight and large surface area, the parachute can increase the air resistance encountered when the object falls, and the object can fall slowly.

How does a kite fly into the sky?

The founder of Mohism, which was popular during the Spring and Autumn Period and the Warring States Period, was Mozi. It is said that he invented the kite, but it was made of wood and was called a wooden kite. After Cai Lun made paper in the Eastern Han Dynasty, the material of the kite was changed to paper, which was called a paper kite. Later, someone tied a bagpipe on the paper kite, so when the wind blew, the paper kite would make a bagpipe sound. This kind of paper kite that can make sounds is It's called a kite.

The principle of Kongming Lantern

How do sky lanterns fly into the sky?

Sky lanterns, also known as Kongming lanterns, are said to have been invented by Kong Ming during the Three Kingdoms period. They were used to convey military sentiments. Later they spread to the people and became a tool to eliminate disasters and pray for blessings.

1. Kong Ming designed sky lanterns by taking advantage of the phenomenon of hot air rising.

2. The bottom of the sky lantern is heated so that the air inside expands due to the heat. However, due to the limited volume of the sky lantern, the excess air will escape from the sky lantern, causing the average density of the entire sky lantern to be less than the density of the external air. Therefore, the sky lantern can fly into the sky.

3. In addition to sky lanterns, humans also invented hot air balloons using the principle of thermal expansion.

summary:

1. The process of falling objects is affected by two forces in opposite directions: gravity and air resistance.

2. Since the air resistance is proportional to the windward area of ​​the object, and the parachute is characterized by its light weight and large surface area, the parachute can increase the air resistance encountered when the object falls, and the object can fall slowly.

3. Changing the temperature of the gas can change the buoyancy of the gas in the air!

Keywords: Little Parachute teaching courseware, E-education version fourth grade science PPT courseware download, second volume, fourth grade science slide courseware download, Little Parachute PPT courseware download, .PPT format;

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

"Little Parachute" PPT courseware 2:

"Little Parachute" PPT courseware 2

Review the past and learn the new

1. Air can occupy a certain space. Based on this, what characteristics do you think air has?

2. What are the applications of compressed air in daily production and life?

1. Characteristics: Air can be compressed, compressed...

File Info

Update Time: 2024-11-22

This template belongs to science courseware Fourth-grade science volume 2 of the E-education edition industry PPT template

Preview