The answer to the exercise book in the second volume of the third grade
First, the growth and change of plants.
1, the beginning of a new plant life
1, true or false.
( 1)√ (2)√ (3)× (4)√
2. Omission
3. For example: the life of kidney beans
Plant seeds
flower
Seeds germinate and take root.
Grow fruit and mature.
Grow stems and leaves
Step 2 plant our plants
1. According to the sequence of planting impatiens and sowing, write the corresponding serial number in the brackets below.
( 1)——(4)——(2)——(3)
2. True or false.
( 1)√ (2)× (3)× (4)× (5)√
3. Read the material and answer the questions.
( 1)A (2)B (3)B (4)C
4. My impatiens growth diary. leave out
3. We saw the root first.
1.( 1) Grow roots first, then stems and leaves; Growing underground is faster. (2) no.
3. True or false.
( 1)× (2)√ (3)× (4)√ (5)√
(6)√ (7)√ (8)× (9)√
4. The seeds become seedlings.
1, true or false.
( 1)√ (2)× (3)√ (4)√ (5)√
3. short answer questions.
(1) key point: potted plants in the glass cover can use carbon dioxide exhaled by mice to carry out photosynthesis and release oxygen for the mice in the glass cover to breathe, so the mice will not suffocate for a short time because the air is not circulating.
(2) Key points: The leaves of Impatiens balsamina are all flat and cross-grow at the nodes of the plant. From top to bottom, they take turns.
The longer the stem, the higher it is.
1, true or false.
( 1)√ (2)× (3)√ (4)× (5)×
2. multiple choice questions.
( 1)A (2)A
3. Observation records and analysis. leave out
Step 6 blossom and bear fruit
1, true or false.
( 1) √ (2) √ (3) √ (4) ×
2. multiple choice questions.
( 1)A (2)A (3)A (4) A
3. Drawing and recording. leave out
7. Our bumper harvest
1, true or false.
( 1) × (2) × (3)√ (4)√
2, omitted.
3. Omit.
Unit exercise of plant growth and change
1, fill in the blanks.
(1) Seeds (2) Selecting seeds (3) Moisture and minerals, and fixing (4) sunlight, carbon dioxide and water.
2. True or false:
( 1)√ (2)√ (3)× (4)× (5)√ (6)√ (7)√ (8)√
3. multiple choice questions.
( 1)A (2)C (3)B (4)C
4. Connection problems.
(1) Erection of sweet potato stems (2) Support and transportation of roots
The stems of impatiens are intertwined to make nutrients.
The stems of morning glory climb up the stems and leaves to develop fruits and seeds.
Absorption and fixation of stolon flowers in grape.
5. Omission
Life cycle unit of animals
First of all, the new life hatched from silkworm eggs
1. Multiple choice problem
( 1)A (2)C(3)B (4)B (5)C(6)A
Observe silkworm eggs
Silkworm eggs are a little concave in the middle and so on.
Second, the growth and change of silkworm
1. A, D, E, F, S
2. Observe the silkworm baby.
( 1)A、C、D(2)B、D(3)B (4)A、C
leave out
4. A, C and B
Third, the silkworm has changed a new look.
1.
2.b、C、D、F、G、H、I
leave out
4. What has the silkworm chrysalis become?
1.
2. Observe the silkworm moth and answer the following questions.
(1) is divided into three parts: head, chest and abdomen, with 1 pair of antennae on the head.
(2) Two pairs of wings, three pairs of feet, long eyes and mouthparts.
3. Water turtles, bees, butterflies, ants, locusts
Five, the life cycle of silkworm
1. Multiple choice problem
( 1)B (2)A (3)B)
leave out
3. Count the time of silkworm baby's life experience.
Larval stage (33-35 days)
Pupal stage (10- 13) days.
Moth stage (6-8 days)
Total days (49-56 days)
Six, the life cycle of other animals
1. True or false.
( 1)√(2)×(3)√
2. mapping.
From eggs: fish, frogs, chickens, mosquitoes, locusts and flies.
Directly born by the mother: cats, dogs, people.
Pervert: mosquitoes, locusts, flies, frogs.
Not abnormal: fish, dogs, cats, people, chickens.
Seven, our life cycle
1. With the growth of age, the height and weight are increasing, and the proportion of all aspects of the body is also changing.
2、
Main characteristics of physical changes
oneself
Short stature, delicate skin, rapid growth in weight and height, etc.
Mom and dad.
He is tall, his skin is old, and his weight and height are relatively stable.
Grandpa and grandma
The skin is old, wrinkled and a little camel.
Unit exercise
1, true or false.
( 1)√ (2)×(3)√(4)√(5)√(6)√
2. Multiple choice problem
( 1)A (2)C (3)B (4)A (5)A (6)B
3. Contents
Please write down three kinds of insects: butterflies, locusts, ants, dragonflies and so on.
4. Omission
Unit "Changes in Temperature and Water"
I. Temperature and thermometer
1. Fill in the blanks.
(1) Temperature Celsius (℃)(2) Thermometer
2.0℃、37℃、 100℃、-7℃、 13℃、-5℃
3.
Is this a centigrade thermometer? be
(2) Each scale on the thermometer indicates 0.65438 0℃.
(3) The highest temperature it can measure is 42℃ and the lowest temperature is 35℃.
Xiaoming's current temperature is 39℃.
Does he have a fever? Yes (I have a fever)
Secondly, measure the temperature of water.
1. True or false.
( 1)√ (2)√ (3) ×(4)× (5)√
2. Are these methods correct when measuring water temperature?
(1) Hold the upper end of the thermometer. ( √ )
(2) Immerse the lower end of the thermometer in water. (√ )
(3) The thermometer does not touch the bottom and wall of the container. (√ )
(4) Wait until the liquid column is stable (no longer rising or falling). ( √ )
(5) When reading, the thermometer does not leave the measured water, and the eyes look up at the liquid level of the thermometer. (√ )
3.
(1) The temperature drops gradually, dropping by 2℃ per minute.
(2) It shows that the heat of water is decreasing.
(3)20℃
Third, the water is frozen.
1. What kind of object is ice? (Please tick the corresponding brackets)
Colorless (√) white ()
Transparent (√) opaque ()
Tasteless (√)
There is no certain amount () but a certain amount (√).
There is no definite shape (√) but a definite shape (√).
Liquid () solid (√)
leave out
3. Fill in the blanks.
(1)0℃ (2) temperature change (cold) (3) colorless, odorless, transparent, with a certain volume, etc.
Fourth, the ice has melted.
1, omitted
2. multiple choice questions.
( 1)C (2)C (3)B (4)B (5)A (6)A
5. Where do the water drops come from?
1, multiple-choice question.
( 1)E (2)D (3)A (4)A
2. When it is hot and wet in a cold outdoor room in winter; In particularly humid weather.
3. When you see water droplets on the glass.
Six, water and steam
1, fill in the blanks.
(1) politics and law (2) gas and water vapor (3) condensation
(4) The ground is dry after the rain, and the table is dry after the wet cloth is wiped.
2. True or false.
( 1)× (2)√ (3)× (4)×
3. short answer questions.
(1) The wrapping paper is very cold and the surrounding temperature is high. Water vapor in the air condenses on paper and becomes small water droplets.
(2) Blowing, sunbathing, moisture absorption and hot air drying.
Seven, the three-state change of water
1. True or false.
( 1)√ (2)√(3)√(4)× (5)√(6)×
2. Connection problems.
Cloud water vapor condenses on touching objects when it is cold.
Small water droplets formed by fog and water vapor condensation float at low altitude.
Dew water vapor is condensed into small water droplets and floats in the sky.
When the water vapor in the lower layer of the frost layer cools below 0℃, it becomes ice crystals.
The water vapor in the snow cools below 0℃ and becomes ice crystals.
3. short answer questions.
(1) all belong to water and are different forms of water.
(2) Water is constantly circulating between land and sea, so the water in the river is inexhaustible.
Unit exercise
1, true or false.
( 1)×(2)√(3)×(4)× (5)×(6)√(7)√(8)×
2. multiple choice questions.
( 1)B(2)C(3)C(4)A(5)B(6)B(7)C(8)C
3.35℃、6℃、-4℃
4. Connection problems.
The water vapor of clouds and fog condenses on the contacted objects when it is cold.
Water droplets condensed from dew vapor float in the air.
The vapor of frost and snow will become ice crystals when it is cooled below 0℃
Ice water solidifies below 0℃
Unit "magnet"
1. Our understanding of magnetism
1, (ring) magnet (round cake) magnet (bar) magnet (u-shaped magnet)
2. Omission
leave out
2. Magnets are magnetic.
1. Judgment
( 1)√(2)√(3)√(4)√(5)×
select
( 1) B (2)
3. B, C and A
3. The poles of the magnet
1. Fill in the blanks.
(1) magnetic pole and two (2) attract and repel each other.
select
( 1)B (2)C (3)C (4)B
Four. Interaction of magnetic poles
1. Fill in the blanks.
(1) Antarctic, South, Arctic, North
(2) Attraction, repulsion and attraction
(3) Antarctica
2. True or false.
( 1)×(2)√ (3)√ (4)×
5. Will the magnetic force change?
1. True or false.
( 1)√ (2)√(3)× (4)√ (5)√(6)× (7)×
Get bigger and smaller.
Step 6: Compass
1. Fill in the blanks.
(1) magnet, magnetic needle (2) azimuth disk, South Pole and North Pole (3) omitted.
2. multiple choice questions.
( 1)C (2)B (3)C (4)A
3. short answer questions.
Both a compass and a suspension will do.
7. Make a compass
1. True or false.
( 1)√ (2)√ (3)√(4)√
2. multiple choice questions.
( 1)B (2)A(3)C
leave out
Unit exercise
1. Fill in the blanks.
(1) magnetic (2) unipolar, heteropolar (3) magnetic poles, two.
2. True or false.
( 1)×(2)√(3)×(4)√(5)×(6)×(7)×(8)×
3. multiple choice questions.
( 1)B (2)A (3)A (4)C (5)A
4. Experimental problems
(1) suspension method, compass test, etc.
(2) Mutual attraction, because opposites of iron attract.
(3) Use a piece of A to suck the middle of another piece of B. If it can suck, A is a magnet; If you can't smoke, A is iron.
Comprehensive exercise
1, fill in the blanks.
(1) grow roots first, then stems and leaves; Growing underground is faster.
(2) absorption and fixation; (3) Support and transportation of head, chest and abdomen, abnormal situation
(4) Birth, growth and development, reproduction and death (5) Expansion with heat and contraction with cold at℃,℃
(6) evaporation, liquefaction (or condensation) (7) Antarctic, S; North pole
(8) Sina, North and South
2. True or false.
( 1)× (2)× (3)√ (4)√ (5)√ (6)×
(7)× (8)√ (9)× ( 10)√
3. multiple choice questions.
( 1)A(2)C(3)A(4)C(5)B(6)C(7)A(8)C
Fourth, fill in the blanks.
( 1)
(2) 100C -50C
(3)
(4) If you can't see the picture clearly, you can refer to the illustrations in the textbook.
Verb (abbreviation for verb) short answer:
Key points: Most plants can make their own "food"-nutrients to meet the needs of plant growth. These nutrients are made from green leaves of plants. They rely on the energy provided by sunlight and make use of carbon dioxide and water. This effect is called photosynthesis and is expressed by the following formula:
Sixth, experimental questions.
Key point: there are two ways, only one way, and it is very important. First, tie the middle of the magnet with a thread and hang it in the air until it stops. One end of the guide rail is the South Pole, and the north end is the North Pole. Second, use one pole of the magnet with known north and south poles to approach. If they attract each other, the magnetic poles are just opposite; If they are mutually exclusive, the poles are the same.