A few questions about science in the sixth grade of primary school, please!!!!

1.The following substances change in form when they change are (a)aThe glass shattered into pieces bGasoline burns cEgg shells are placed inside the vinegar.

2.Observe the parts of the bike. Think about it, what methods are used to prevent rust on these parts? And write it out.

There's a lot of that, right?

Chains are generally organic oils, which is one way.

There are also bodies that are generally painted.

There is also a car bar and a bicycle forum with chrome rims.

Stainless steel ingredients are added at the time of manufacture.

These can prevent rust.

When the sugar is heated, it slowly melts into a liquid form, and if it is heated continuously, it becomes coke-like. At what step in the process did not generate new matter, and which step did it generate new matter? Explain why.

The beginning of melting is a physical change.

Scorching is a chemical change.

Question 1: BC gasoline combustion and eggshell vinegar will have a chemical reaction.

Question 2: Ways to prevent metal rusting:1The surface is covered with an anti-oxidation film such as: painted, oiled on its surface.

2.Use anticorrosive metals: the surface of steel can be coated with zinc.

Paint, oil.

3.There is no new substance in the first step, and there is a new substance in the second part. Because the first step is a physical change, while the second step is a chemical change.

There is an answer in the back of the science book, or the teacher didn't ask us to do it.

Content from user: soybean sprouts.

5th grade science book 2 review questions.

1. I'll fill in: (2 points per grid, 30 points in total).

1. The direction of the earth's rotation is from west to east, and the direction of the earth's revolution is from west to east.

2. In ancient China, a day and night were divided into 12 hours, and each hour is equivalent to 2 hours now.

3. The unified time adopted in China is called Beijing time.

4. Press the styrofoam block into the water, and the hand can feel that the styrofoam block has an upward force, which we call the buoyancy of water

5. The volume of general objects expands when heated and shrinks when cooled.

This change in the object is called thermal expansion and contraction

6. The sinking and floating of the object are related to the volume, weight, material and other factors of the object.

7. Heat is always transferred from the hotter end to the cooler end.

Second, let me judge: (the right hit, the wrong hit.) 1 point for each question, 15 points in total).

1. There is a speed at which time passes.

2. The cargo ship enters the sea from the Yangtze River, and the hull will float some.

3. All objects in nature have the property of thermal expansion and cold contraction.

4. The body feels warm after wearing more clothes in winter because there is a lot of heat in the clothes.

5. There are long days or long nights in the polar regions of the year.

6. If you sit in a car driving forward, you will see trees and houses moving backwards on both sides.

7. New Year's bells are ringing at the same time all over the world.

8. Bridges made of steel are usually erected on rollers, and the role of rollers is to make the car drive more stable.

3. I will choose: (Each question a.)

(1) Cut a circle and put it together into an approximate rectangle whose width is equal to the radius, the circumference of this rectangle is centimeters, the radius of this circle is (2) centimeters, and the circumference is (centimeters.

2) When the area is equal, the circumference of a square, rectangle, parallelogram and circle is the largest (parallelogram).

Float by.

1. Many intersecting food chains form a complex (food web.

2. Dinosaurs were (reptilian) animals in ancient times.

Food webs crawl hugely.

1.Food web.

2.Crawl. 3.Mimicry.

4.Solar energy.

5.Archaeopteryx.

6.Copernicus.

Theory of the Movement of Celestial Bodies).

7.Reduces water evaporation.

transpiration) 8.Stop it.

9.Survived in the rocks.

Animal or plant remains.

The answer should be correct.

1 Food web.

2 crawling, 3 camouflage.

4 Suns 5 Archaeopteryx.

6 Copernicus, The Motions of the Heavenly Bodies

7. Reduce water evaporation.

8 stops and 9 survive in the rocks.

The bones of animals.

1.Food web.

2.Crawl. 3.Mimicry.

4.Solar energy.

5.Archaeopteryx.

6.Copernicus.

Theory of the Movement of Celestial Bodies).

7.Reduces water evaporation.

transpiration) 8.Stop it.

9.Survived in the rocks.

Animal or plant remains.

1.Is the magnetic force of an electromagnet related to an electric current?

2..The magnetic force of an electromagnet is related to the electric current.

3.The number of battery compartments.

4.The thickness of the wire does not change, and the size of the iron nail does not change.

What is the magnetic force of the electromagnet related to the wire of the ear of the ear is related to the wire, and the thickness of the wire of the battle group is kept unchanged with wires of different thicknesses.

You don't want to make a mold grinding??? Raid ??? Code ???

Science experiment: Buy a large balloon, blow one in the atmosphere, and find a way to measure the mass of the air in the balloon.

Experimental method design:

Equipment used in the experiment:

Procedure: (Write step by step):

Record of Experimental Results:

Materials: Xiaoice cubes, pebbles, test tubes, test tube clips, candles, matches or lighters.

Procedure: Put the Xiaoice cube into the test tube, press it with a small stone, light the candle, and put the test tube on the fire to burn.

Result: After a while, the water above the test tube boiled, and the ice had not yet melted.

Principle; When the tube is heated, the hot water rises and the cold water falls, so until the water above the tube boils, the water below has not had time to melt the ice.

Method: Calculated according to mass.

Equipment: Large glassware with graduation marks, glass rods.

Process: Blow the balloon into the appropriate amount of gas, fill the large glassware with the appropriate amount of water, and mark the table at the scale mark of the water as V1; Tie the balloon to keep it airtight, press the balloon completely into the water of the glassware with a glass rod, and mark the current liquid level position as V2.

Result: The volume of the balloon is denoted as v2-v1 The mass of the balloon is calculated from mass = density * volume.

1. Wrong. Baby fish and crocodiles are amphibians;

2. Right; 3. Wrong. The input is electrical energy, the output is light energy, and the heat energy is the wasted part;

4. Right; 5. Right. From the point of view of a primary school student, it can be said that this question is correct;

6. Right; 7. Right;

8. False. The constellation Ursa Major is the Big Dipper, which is visible year-round in the Northern Hemisphere;

9, right; 10. False. Ore fuels, combustion can cause pollution (car exhaust, etc.).

Answers to supplementary questions:

2.The time for the earth to revolve around the sun is 365 days, and the earth revolves around its axis for about 24 hours, and the alternation of day and night is also about 24 hours (right);

3. Wrong. Morning glory blooms during the day, and primrose blooms at night;

4. Wrong. Circumnavigating the globe is Magellan;

1 The magnetic force of the electromagnet is not related to the thickness and length of the coil. (Yes, it is related to the amount of power and the number of turns of the coil);

2. Wrong. The answer is the same as above;

3. Wrong. The self-made electromagnet has low voltage and few coil turns, so the efficiency of electric energy use is very low, the power consumption of the wire itself is very small, and the power consumption of the electromagnet has nothing to do with the wire;

4. Wrong. All changes in the relative state of motion are energy-intensive. The stone rolling down the mountain is the conversion of gravitational potential energy into kinetic energy and the loss of heat energy;

5. Right. 7. Right; Only gymnosperms and angiosperms bloom;

8. False. The largest number should be protozoa.

1. (x) Baby fish and crocodiles are not fish.

2. (x) This energy is obtained from food, and energy is obtained not only from food, but also in other ways.

3. (x) The input energy is electrical energy, and the output is thermal energy. He said the opposite.

4. (x) It should be 1 kilowatt of electrical appliances, and the power consumption for 1 hour is 1 kWh.

5, (right) 6, (right).

7, (right) 8, (x) Ursa Major and Leo can be seen all year round, but April in spring is the best time to observe them.

9. (x) Ocean transportation and coastal tourism should not belong to the "method of developing and utilizing marine resources".

10. (x) It will have an adverse impact on the environment.

1. Wrong. 2. Right;

3. Wrong. 4. Right;

5. Right. 6. Right;

7. Right; 8. False.

9, right; 10. False.

The following substances that are not crystals are (c) a table salt, b diamond, c glass.

2. The most important feature of the lunar topography is that there are many different (b) compositions. A mountain range, B crater, C regular mountain.

3. Candle burning belongs to (C) Change: A Chemistry, B Physics, C Chemistry, and Physics.

4. The world is composed of (a) a substance, b crystal, c rock color.

5. The first person to invent and propose the name "cell" was (a) A Leeuwenhoek B Robert Hoek C Darwin.

6. The increase in the concentration of (b) in the atmosphere is the increase in the temperature of the earth's surface A sulfur dioxide b carbon dioxide c monoxide.

1, C glass is a mixture;

2,B3,C Wax core is chemical, wax oil is physical;

4，a5，a

6,b A lot of people gather in the classroom and exhale a lot of carbon dioxide, so usually the classroom is hotter than the outside, isn't it? 7，a

1：c2：b

3：c4：a

5: A detailed explanation.

6：b7：a

Well, I don't know what you think. I'm in high school, and these are pretty straightforward.

Answer: When turning to position 1, the Northern Hemisphere sunlight (directly hitting the Northern Hemisphere (Tropic of Cancer)) shoots, which is the (summer) season; The Southern Hemisphere sunlight (direct to the Southern Hemisphere (Tropic of Capricorn)) shoots, and it is the (winter) season.

Note: The figure is: a globe on the top and bottom, a candle in the middle, a globe on the left is 1, then the lower one is 2, the right one is 3, the upper one is 4, there is an arrow between the two globes, and the arrow is rotated counterclockwise.

At 1 o'clock the sun shines directly on the northern hemisphere (Tropic of Capricorn), and in summer the sun shines directly on the equator because it is counterclockwise, 2 is autumn and 4 is spring. At 3 o'clock, the sun shines directly over the Southern Hemisphere (Tropic of Capricorn) in winter.