Junior 2 Science Sinking and Floating Conditions of Objects and Their Applications

1 Because the heat is upward, the plastic bag rises, and after a while, the heat runs away and falls down 2. 409kg follow-up question: The second question should be arithmetic, specific!

The answer is useless!! Help : m=p*v=

45*10 3 times per cubic meter * cubic meter = 6 wooden sticks: *6 = 409kg A:

Standard Answer!

The ups and downs of the manuscript god body and the application knowledge points are as follows:

The floating and sinking conditions of the object are f floating》g, and its application is a submarine, and the force of the object immersed in the fluid is called buoyancy when the fluid is vertically uplifted, and the buoyancy refers to the difference (resultant force) between the surfaces of the object in the fluid (liquid and gas).

A fluid is a fluid substance, and it is an object that continuously deforms a yard of limbs when subjected to any tiny shear force. Fluid is an umbrella term for liquids and gases. It has easy flowability, compressibility, and viscosity.

Sinking: Matter >> liquid, g >> f float, m = m row.

Suspension: Matter = liquid, G matter = F float, M matter = M discharge.

Floating: Matter < liquid, g matter floating: Matter < liquid, g matter = F floating, m matter "m row.

Sinking bottom: matter》 liquid, g = f float + f bottom support force of matter, f float: density, g: gravity, f: force, m: mass.

An object submerged in a liquid floats up if its density is less than that of the liquid; If its density is equal to the density of the liquid, the object is suspended; If its density is greater than that of the liquid, the object sinks.

Application of the Floating and Sinking Conditions of Objects:

1. Steamship. 2) Displacement (m row): The quality of the water discharged when the ship is fully loaded.

f float = m row g while f float = g.

M ship + M cargo = M row.

2. Submarines.

How it works: Float and dive by changing its own gravity.

3. Balloons and airships.

Working principle: The inside is filled with gas with a density less than the density of air to achieve floating. Similar to a hot air balloon, the flame expands the heated volume of the air in the balloon, reducing the density and lifting it into the air.

4. Density meter.

The density meter is an instrument that measures the density of liquids, and the scale is small at the top and large at the bottom, thin at the top and dense at the bottom, and it is not uniform.

How it works: The condition for an object to float on the surface of the liquid is floating g.

The floating and sinking conditions of the object are f floating" g, which should be used as a submarine, and the force of the object immersed in the fluid is called buoyancy when the fluid is vertically uplifted, and the buoyancy refers to the difference between the fluid pressure (net force) of the surface of the object in the fluid (liquid and gas).

A fluid is a fluid substance, and it is an object that will be continuously deformed by any small shear force that is spaced by any microscopic void. Fluid is an umbrella term for liquids and gases. It has easy flowability, compressibility, and viscosity.

The buoyancy experienced by an object is related to the density of the liquid and to the volume of the liquid being discharged. Buoyancy is related to the density of the liquid and the volume of the discharge, but not to the mass and volume of the object itself.

When the top interface of a buoy does not touch the liquid, only the pressure acting upward on the bottom interface will produce buoyancy. As for an object located on the bottom surface of the container, this phenomenon is not much, because as long as there is a thin liquid film in between, the pressure can be transmitted, and there is upward pressure on the bottom surface, and there is a pressure difference between the upper and lower surfaces of the object, and the object will be subject to buoyancy.

1. The sinking and floating conditions of the object in the liquid.

It is determined by the buoyancy of the object and the gravity of the body.1 When the F float is greater than the G object, it floats; When f float is equal to g matter, the object is in a floating state (v row is less than v object 0

2) When F float is equal to G matter, suspension (V row is equal to V matter) 3) When F float is small and G matter is, sink (G matter = F float + F support force).

1. Float and sink condition is a physical term, which refers to the object immersed in the liquid of the earth, which is subjected to two forces: vertical downward gravity and vertical upward buoyancy, the magnitude of these two forces determines the motion state of the object in the liquid. Depending on the magnitude of the buoyancy and gravity experienced by the object, there are three scenarios for the buoyancy and sinking of the object.

2. If the density of the object immersed in the liquid is less than the density of the liquid, the object will float up; If its density is equal to the density of the liquid, the object is suspended; If its density is greater than that of the liquid, the body sinks.

The floating and sinking conditions of objects and the application teaching design are as follows:

1. Teaching Objectives.

Knowledge and Skills Objective] Know the floating and sinking conditions of objects, understand the floating principle of ships, the floating and sinking principles of submarines, and the lifting and lowering of balloons and airships.

Process and method objectives] Through experiments and force analysis, the floating and sinking conditions of the object are obtained; Through the observation and analysis of the demonstration experiments, we will understand how the ship floats on the water and other applications of buoyancy.

Affective Attitudes and Values Objective] Preliminary understanding of the impact of science and technology on social development, and initial establishment of awareness of applying physical knowledge to solve practical problems.

Second, teaching is important and difficult.

Focus] The floating and sinking conditions of the object.

Difficulty] application principles of ships, submarines, balloons, airships, etc.

3. Teaching process. Rent respect.

Student] Some are on the surface, some are in the water, and some are at the bottom.

Teacher] Everyone knows that if you throw a piece of iron in the water, it will definitely sink, so why does the ship not sink if it is iron? Why is a submarine suspended in water? Why does the stone sink and the wood rise?

What is the relationship between the floating and sinking conditions of an object? After this lesson, we can all solve it.

Session 4: Summary of homework. Understand the float and sink conditions of memory liquids, and use the float and sink conditions to explain the principle of density meters.

Fourth, the design of the board book.

5. Reflection on teaching.