Department : Science
Cairo Governorate
Nozha Directorate of Education
Nozha Language Schools
Ismailia Road
Form
:6th prim.
Revision Sheet 2014
Unit(1) Levers
• Levers are the first simple machines man used to perform heavy
tasks easily.
• Archimedes is a Greek scientist who first described levers.
Levers: It is a rigid bar that rotate around a fixed axis called fulcrum, and affected by
two forces (effort force and resistance force).
Fulcrum (O):
The fixed point which the bar sits on or
rotates around.
Resistance force (R): The force resulting from the weight of the body we want to move.
Effort force (F): The force exerted by a person to equilibrate the resistance.
Functions (importance) of levers:
1. Increasing force: You exert (do) small force to get great effort,
Ex.: crowbar, nutcracker, wheel barrow and bottle opener.
2. Increasing distance: You exert force for a small distance to move an object longer
distance, Ex. :manual broom.
3. Increasing speed of object: hockey bat.
4. Avoid danger: like holding hot, cold or poisonous things
Ex: coal (or ice) holder.
5. Accuracy in performance: Ex.: tweezers helps us to pick up very
small objects.
6. Moving force from one place to another. Ex.: manual boom.
1
Types of levers:
We have three types of levers:
1) First class lever.
2) Second class lever.
3) Third class lever.
Type of lever can be determined according to location of force, resistance
and fulcrum
Mid point
Type of lever
Examples
Scissors, pincer,
pliers, crowbar
(O)
Fulcrum is between effort
force and resistance force
seesaw,
First class lever
Nutcracker, bottle opener,
wheel barrow, stapler
(R)
Resistance is between force
and fulcrum
Second class lever
(F)
Force is between resistance
and fulcrum
Manual broom, hockey bat,
coal holder
2
Sheet one
Lesson (1) Types of levers
A- Complete:
1- …………… is a rigid bar that rotates around a fixed point called
………… and is affected by …………. and ……………..
2- ……………. is a fixed point that the bar rotates around.
3- Levers can be classified into ………… types.
4- In levers of first order the …………. is located between the ……….. and
the …………...
5- In the levers of third order, the ………… located between the …………..
and the…………..
6- The bottle opener and wheel barrow are levers of the ……….. kind,
while the pliers are levers of the ………… kind.
7- The pincers are from the levers of ………. class while the ice holder is
from the levers of the ……….. class.
8- The nutcracker is a lever of ……….. class, while the scissors are a lever
of ………. class.
B- Choose:
1- The effort lies between resistance and fulcrum in the……………….
( Wheel borrow
– pincers – hammer
– sugar holder ).
2- Fulcrum is located between resistance and effort in the ………..
( Nutcracker
– ice holder
– Scissors
– bottle opener ).
C- Give reason for:
1- The seesaw is a lever of first class.
………………………………………………………………………
………………………………………………………………………
2-Levers are very important in our daily life .
………………………………………………………………………
………………………………………………………………………
3
D- Put ( √ ) or ( × )
1- From the functions of levers is decreasing the speed .
( )
2- Archimedes is a Greek scientist , he is the first scientist described the
lever .
(
)
E- What is meant by :
1- Fulcrum …………………………………………………………………….
…………………………………………………………………………………
2- Levers ………………………………………………………………………
…………………………………………………………………………………
F- Mention three of the most important benefits of levers
1- ……………………………………………………………………………..
2- ……………………………………………………………………………..
3- ……………………………………………………………………………..
G-Mention examples of levers used in:
a) Avoiding dangers……………………………………………………………………………………………
b) To move force from one place to another………………………………………………………
c) Be accurate in performance……………………………………………………………………………
4
Lesson (2):
Law of levers
• Any lever is affected by two forces, effort force and resistance force. These two
forces may be equal in value or different in value.
• The relation between resistance force and effort force is determined by law of lever.
Law of lever: Force x its arm = resistance x its arm
Force arm: The distance between effort force and fulcrum.
Resistance arm: The distance between resistance force and fulcrum.
Any force is inversely proportional to its arm.
Force is measured in Newton, while force arm is measured in cm.
When does a lever conserve effort (has mechanical benefit) ?
- When the effort force arm is longer than the resistance arm, so the effort force is
smaller than the resistance.
Types of levers and conservation of effort:
1) First class lever:
We have 3 possibilities
Force arm = resistance arm
So force = resistance, and
the lever doesn't conserve
effort or has no mechanical
benefit.
Resistance arm > F arm.
So force is larger than
resistance, and the lever
doesn't conserve effort or
has no mechanical benefit
Force arm > resistance arm
So force is smaller than
resistance, and the lever
conserve effort or has
mechanical benefit.
First class lever sometimes conserves effort and sometimes doesn't conserve effort.
5
2) Second class lever:
Force arm > resistance arm, so force is smaller than resistance
and second class lever always conserves effort or has mechanical
benefit.
3) Third class lever:
Force arm < resistance arm, so force is larger than resistance
and third class lever always doesn't conserve effort or has no
mechanical benefit.
Notes:
• Only in first class lever we can have F arm = R arm, so we have F = R
• The levers which don't conserve effort are used to avoid danger, increase speed or
distance or for accuracy in performance.
• A lever doesn't conserve effort when :
a) Effort force is larger than or equal to the resistance force.
b) Force arm is shorter than or equal the resistance
6
Sheet (2)
Law of levers
A- Complete
1- The forceps are lever of the third order in which the …………. is longer
than ……………………..
2- Levers of second type save effort because effort arm is always ………..
than resistance arm
3- The levers of first type save effort when the ………… is longer than the
……………………
B) What happens when :
1- The force arm and the resistance arm are equal .
………………………………………………………………………………
2- The resistance force is larger than the effort force .
………………………………………………………………………………
C) Choose
1- When the arm of force is longer than the arm of resistance , the effort
force is ……… the resistance .
( larger than – smaller than – equal to )
2- The effort force and the resistance force is measured in ………….. .
( hertz –
Newton –
meter )
D- Give reason for:
1- Some times the first class levers conserve effort .
………………………………………………………………………………..
………………………………………………………………………………..
2- The force doesn't equal the resistance in the second class lever
………………………………………………………………………………..
………………………………………………………………………………..
E) Write the scientific term :
1- Force × its arm = resistance × its arm .
[…………………….]
2- A type of levers that always conserves effort .
[…………………….]
3- The type of levers , where the effort force is always longer than the
resistance force .
[…………………….]
7
F) Problem :
The length of the force arm of a crowbar is 100 cm and the length of the
resistance of is 15 cm .
If the value of resistance equals 400 Newton , calculate the value of effort
force and mention the type of lever .
………………………………………………………………………………..
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
G) Complete the following table :
Force
Force arm
Resistance
Resistance arm
…………….
10
2
20
4
10
4
……………..
8
Unit(2) Electric energy
• Sun is the main source of light on earth.
• First man used candles, oil lamps and torches.
• Thomas Alpha Edison, is an American inventor who invented light bulb
which replaced all other artificial sources of light in the whole world.
• Electric lamps are preferred than other light sources because they provide light which is
bright, clean and free of smoke, vapor or odor.
Electric lamp: It is a tool used to convert electric energy to light energy by passing
electric current through it.
Electric current: It is the flow of electric charges through a material conducting
electricity.
There are many types of electric lamps; the most popular (common) types are two which
are
a) Light bulb.
b) Fluorescent lamps.
a) Light bulb
• It is the most popular source of light.
• Uses: in lightening houses, car lights and in torches.
Parts of light bulb:
It consists of three main parts:
1) Tungsten filament.
2) Glass bulb.
3) Base of light bulb.
1) Tungsten filament:
Thin coiled wire made of tungsten
Function: It glows (heats) up and emits light when electric current passes through it.
G.R.F.: The filament is made of tungsten.
Because it has a high melting point that protect it from melting at high temperature.
• The filament is connected to copper and lead wires that are connected to base of
light bulb.
Function of copper & lead wires: carry the electric current from the base of the bulb to
the filament.
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2) Glass bulb:
Made of thin glass and filled with inert gas (argon).
Function of glass bulb: Prevent air from reaching the filament, so protect it from burning.
Function of argon gas: Increase the lifetime of the filament by protecting it from burning.
3) Base of the light bulb:
Function: a) Carries the lamp in upright position.
b)Connect the bulb to electric circuit
b) Fluorescent lamps
Parts of fluorescent lamp:
1- Glass tube.
2- Two tungsten filaments.
3- Points of connection.
1.Glass tube:
- Vacuumed glass tube contains argon gas and little mercury.
- Inner surface of glass covered with phosphoric material.
2.Two tungsten filaments:
Found at the two tips from inside (one filament at each tip).
3.Two points of connection:
Connect the lamp to electricity.
Uses of fluorescent lamps:
1) Lightening houses, office and underground metro.
2) Decorating stores.
3) Commercial advertisements.
Note: fluorescent lamp are commonly known as neon lamp although they don't
contain neon.
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Electric circuit:
It is a closed and continuous path through which the electric current passes
• Simple electric circuit consists of:
a) Battery: source of electricity.
b) Lamp
c) Electric wires: carry the electric current from
battery to lamp .
Series connection
Parallel connection
1.lamps are connected one after another
2.Electric current has only one route to pass
through.
3. Intensity of the light decreases by
increasing the number of lamps.
4. Unscrewing, turning off or damage of one
lamp leads to turning off all other lamps
1.lamps are connected in parallel
2.Electric current has many (branching)
routes to pass through.
3. Intensity of the light remains constant
by increasing number of lamps
4. Unscrewing, turning off or damage of one
lamp doesn't affect other lamps
Electric lamps and electric machines in house are connected in parallel. So each lamp
functions alone and the lightening in each room is independent from the lightening in any
other room.
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Sheet (3)
Electric energy
I- Complete:
1- ……………. is the main source of heat & light
2- ……………. a tool that converts electric energy to light
3- The first scientist who invented the electric lamp was ……………. .
4- The fluorescent lamp contains ………… gas and a little of ……………
5- We fill the lamp with ………. gas to stop combustion.
II- Write the Sc. Term:
1- An inert gas that is found in the glass bulb of electric lamp.
[
]
2- The most popular source of artificial light in all houses .
[
]
3- An inert gas isn't used in making the fluorescent lamp but these types of
lamps are known with the gas name .
[
]
4- The part of lamp which protects the filament from burning by isolating
the air
5- The lamp which has 2 filament of tungsten.
[
[
]
]
III- What's the function of :
1- The filament of tungsten in the glass bulb .
………………………………………………………………………………..
2- The glass bulb in the light bulb .
………………………………………………………………………………..
IV- What happens in the following cases :
1- Turning off one light bulb in an electric circuit contains many lamps
connected in series .
………………………………………………………………………………..
2- One of electric lamps burns out , while it is connected in parallel with
others .
……………………………………………………………………………….
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V- Write the label:
1-…………………
2- …………………
3- …………………
4- …………………
5- …………………
VI) Look at the figure in front of you then answers :
1- In this case , the simple circuit is ………………. thus the electric current
passes through .
2- In case that any of these parts is not connected, the ………….. doesn't pass
through the circuit .
3- Write the labels in the figure
1) …………………..
2) …………………..
3) …………………..
4) …………………..
5) …………………..
6) …………………..
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Lesson (2)
Dangers of electricity.
Uses of electricity:
1) Lighten houses, offices, streets, ………………..
2) Cook and preserve food.
3) Operate different machines (TV., radio, computer,…………….)
According to electric conductivity, materials can be:
1) Good conductors of electricity, Ex.: iron, copper and aluminum.
2) Bad conductors of electricity, Ex. : wood ,plastic and glass.
Electric conductor: Materials which allow electric current to flow through.
Electric insulators: Materials which don't allow electricity to pass through.
Can the electricity cause danger?
- Electricity is dangerous if we don't follow the safety precaution in dealing with it.
- Electricity is safe if it is handled with care.
Injuries due to electricity are two types:
1) Direct injury.
2) Indirect injury.
Electric fire:
Reasons of electric fire:
1) Placing electric machines that generate heat (iron, heater,…) near to flammable
materials (carpet, furniture, curtains, rugs causing burning of these materials.
2) Plugging more than one electric machines in the same socket (G.R.F.) because it
cause overload of electricity, so wires heat up and cause fire.
3) Not disconnecting electric current from machines that generate heat after use
(G.R.F.) because it cause rise in temperature of machine and cause it to burn.
G.R.F.: Water is not used to put off electric fire.
- Because water is a good electric conductor, so fire increases and could harm the
rescuers.
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Electric shock:
It results from passing electric current through human body.
• Harms resulting from electric shock depend on :
1. Strength of the current passing in human body.
2. Time the current takes through the body.
Reasons of electric shock:
a) Part of your body touches an electric wire and the other part of your body either
touches the ground or touches a good electric conductor (metallic chair) which is
connected to ground.
b) You touch two electric wires connected to electricity.
Electric burns:
Damage of tissue due to electricity.
Reasons of electric burns:
a) Your body touches electric current and causing shock which leads to burn.
b) Touching electric fire or spark resulting from electric fire.
c) Touching electric machines that generate heat (iron, heater,….)
Precautions in dealing with electricity:
1) Don't play with electric connection. or touch naked wires .
2) Don't place several machines in one socket.
3) Disconnecting electric machines after use.
4) Don't place any metallic objects in the socket.
5) Place a piece of plastic in the socket.
6) Don't place electric machines that generate heat close to furniture.
7) Don't leave electric machines connected to electricity while having a bath.
15
Sheet (4) Dangers of electricity.
I- complete:
1- Iron is considered as an electrical ……………., while wood is considered
as an electrical …………………
2- Electricity is used to lighten ……………… and …………….
3- The harms resulting from an electric shock depend on …………………
passing in the human body and also on …………………..
II- Mention some of important precautions when dealing with electricity
( only 3 points )
a) ………………………………………………………………..
b) ………………………………………………………….……..
c) ………………………………………………………….……..
III - Give reason for:
1- The electric heater must not be placed close to furniture or rugs .
………………………………………………………………………………
2- We must place a piece of plastic in the socket.
………………………………………………………………………………
3- Impure water is not used to put out electric fires .
………………………………………………………………………………
4- You have an electric shock if you touch a source of electricity.
………………………………………………………………………………
IV- Write the scientific Term:
1- A closed path that the electric current passes in.
[……………….]
2- It’s caused by neglected the safety precautions that have to be followed
while dealing with electricity.
[……………….]
3- The materials that allow the electric charges to flow through them .
[……………….]
4- The materials that don’t allow the electric charges to flow through them .
[……………….]
16
V- What happens it:
1- If you touch a source of electricity which your hands.
………………………………………………………………………………
2- A piece of glass is inserted in a closed electric circuit .
………………………………………………………………………………
3- If we place several connections in the same socket.
………………………………………………………………………………
VI- Put ( √ ) or ( × ) and correct the wrong one :
1) Electric shock occurs as a result of passing an electric current through
human body .
2) Water is used to put off regular fire
.
3)The human body is bad conductor for electricity.
17
(
)
(
)
(
)
Unit Three
Lesson (1): Solar eclipse
• Earth revolve around the sun in oval orbit, also the moon revolve around the earth in
oval orbit.
Remember :
• Moon appears larger in size when it is nearer to earth ?
• Moon appears smaller in size when it is farther from earth (rotate in higher orbit from
earth.
• Shadow is formed due to travelling of light in straight line.
• When the dark circle of the moon passes in front of the sun, shadow of the moon is
formed.
Solar eclipse:
An astronomical phenomenon occurs when the earth, moon and the sun are
in one straight line with moon in the middle.
In solar eclipse, the moon casts its shadow on earth hiding the sunlight from part of the
earth.
• DuraƟon of solar eclipse is 7 minutes and forty second (7 minutes and few seconds)
Shadow area of the moon is called Umbra, while semi-shadow area is called Penumbra
Types of solar eclipse:
1) Total solar eclipse.
Total solar eclipse
The moon completely hides
the sun
Occurs in the shadow area
(umbra) of the moon
2) ParƟal solar eclipse.
Partial solar eclipse
The moon hides part of the
sun
Occurs in semi shadow of
the moon(penumbra)
3) Annular solar eclipse.
Annular solar eclipse
The sun appears like lighted
ring
Occurs when the moon is in
higher orbit from the earth
(smaller in size)
Give reason for :
• Looking at solar eclipse requires use of special glasses
To protect the eyes from harmful sun rays where it affects the retina (ultraviolet and
infrared) that may cause blindness.
18
What happens if:
• You focus looking to sun during solar eclipse.
It will harm the eye and may cause blindness
Important terms:
Umbra (cone umbra):
Dark inner shadow where total solar eclipse occurs.
Penumbra:
Faint outer shadow where partial solar eclipse occurs.
Total solar eclipse:
A type of solar eclipse where we can't see the sun completely and formed in umbra
of the moon.
Partial solar eclipse:
A type of solar eclipse where we can see only part of the sun and formed in
penumbra of the moon.
Annular solar eclipse:
A type of solar eclipse where the sun appears like lighted ring and formed when the
moon is in higher orbit from the earth.
19
Sheet (5)
Solar eclipse
A- Complete:
1- ………… occurs when earth, moon and sun are nearly on one straight
line with the moon in the middle.
2- ………… hides the sunlight from us and a ………. of the moon is
formed.
3- There are three types of solar eclipse which are ………….,………… and
………….
4- Doctors warn of ……………. as its rays ……….. and can lead to
…………… within few minutes.
5- When the earth lies in the semi – shaded area of the moon , we can see a
……………. of the sun what's known as ………………
B- Correct the underline words :
1- In the semi-shaded area of the moon , we can see a part of the sun forming
the total solar eclipse .
2- The semi- shadow is called umbra .
3- The solar eclipse always occurs at night .
C- Identify the astronomical phenomena in the following figure then
answer :
1- What does the figure show ?
……………………………………..
2- Label it .
1) …………………..
2) …………………..
3) …………………..
4) …………………..
20
Lunar eclipse:
It occurs when sun, earth and moon are in one straight line with earth in the middle
• The moon enters the shadow of the earth.
• Duration: One to two hours. It can be seen easily from any place on earth.
• Rate: Twice a year, in the middle of the lunar month.
• It occurs at night, when the sun is behind the horizon.
•
Lunar eclipse doesn't require special glasses to look at it as it doesn't harm the
eyes.
Give reason for: In the start of total lunar eclipse, the moon appears red in color.
- Because the earth's atmosphere can't absorb the red rays of the sun.
What happens when: The moon enters the semi-shaded area only.
- The moon light turns faint without being eclipse.
21
Sheet (6)
The lunar eclipse
A- Complete:
1- Lunar eclipse occurs when earth hides ……….. or a part of it from
moon at a rate of ……….. lunar eclipses per year.
2- When the earth comes between moon and sun, lunar eclipse will be
……………….
3- The lunar eclipse becomes ………… if the moon falls in the penumbra
area.
4- There are two types of lunar eclipse which are ……….. and ……………
5- The lunar eclipse occurs in ………… of lunar month.
6- We can see …………….. when the sun is behind the horizon at night ,
where…………… always occurs in the morning .
7- Solar eclipse does not last more than …………. minutes and ……………
. Seconds , whereas the duration of ………….. eclipse last for more than two
hours .
8- The color of the moon tends to be …………….. during the start of the
…………… lunar eclipse .
B- Put ( √ ) or ( × )
1- Two phenomena of lunar and solar eclipse are repeated regularly and can
be predicted
(
)
2- When the cone shadow doesn’t reach earth surface so annular solar
eclipse can be observed.
(
)
3- We can observe the lunar eclipse with naked eye.
(
)
4- The lunar eclipse occurs in the morning.
(
)
5- The time of solar eclipse is less than the time of lunar eclipse. (
)
C- What happen when :
1) The moon comes in an orbit higher from earth .
…………………………………………………………………….…………..
2) The moon enters the earth's umbra .
…………………………………………………………………………………
22
D- Write the scientific term :
1- Rays that can't be absorbed from above the atmosphere to the earth , that
causes red color of the moon in the start of lunar eclipse . [……………]
2- The Earth's shadow in which total lunar eclipse is formed . [……………]
E- Correct the underlined word :
1) Lunar eclipse occurs in the middle of the lunar month two times a month .
2) The phenomenon of the lunar eclipse occurs in the end of the lunar month
3) The solar eclipse occurs when the earth comes between the moon and the
sun.
F- The following figure represents an astronomical phenomenon :
1- What's the name of this phenomenon ?
……………………………………………………………………………..
2- Label the figure :
1) ………………
2) …………………
23
3) ………………..
G.R.F.: Since the past man was concerned with observing stars and planets.
- To understand the astronomical phenomenon that occurs in the sky.
Babylonians role:
They discovered that the moon returns back to same point where solar or lunar
eclipse occurred every 18 years and 11 days.
Arab scientists:
• They used to detect the month's crescent on top of mountains and minarets (to get a
clear vision)
• They noticed the movement of sun, moon and planets.
Al Hassan Ibn Elhaithem:
He proved that vision occurs due to amount of light emitted or
reflected from object on eyes.
• Based on Ibn-Elhaithem theory, scientists came with the idea of
collecting greater amount of light rays from stars and planets
(idea of telescope)
Galileo:
• He made his own telescope.
• He used lenses in his telescope.
• He was the first one to see mountains on the moon.
Telescope:
A device used to collect light from distant object like stars and planets
(It forms magnified photos of celestial bodies)
• Some telescopes used lenses to collect light rays, others used mirror.
• Types of telescope depends on the type of rays they collect (Visual light, infrared, or
ultraviolet, electromagnetic waves).
Observatories:
Places where astronomers work and keep their telescopes
Observatories have dome – shape ceiling, which opens at night to
direct telescope to sky
24
Observing space outside the earth:
Man placed telescopes revolving around the earth on space stations
Hubble telescope:
• The most famous space telescope
• Revolves around the earth in orbit 593 Km higher than
sea surface in 1990
• Its length reaches 16 meters.
• Used mirrors to collect light rays.
Satellites:
• Astronomical observatories that study stars and galaxies
from outside the earth's surface.
• Considered as fixed windows at space.
• In 1957, the first satellite (sputnik) was launched in orbit
around the earth
• Now we have many satellites revolve around the earth and
send photos about earth and space.
Galaxies:
Group of millions of stars forming beams of light in extreme dark of space
• Our planet Earth belongs to the solar system which is
found in Milky Way galaxy.
• Milky Way galaxy has spiral shape and four arms, it
contains about two hundered billions of stars.
Solar system:
• Consists of sun ,planets and moons.
• It is found on one of the Milky Way's arms.
• Planets of solar system are classified into:
1) Small rocky planets: Mercury, Venus, Earth
and Mars.
2) Huge gaseous planets: Jupiter, Saturn,
Uranus and Neptune.
25
Sheet (7)
Observing space
A- Complete :
1- ………………..was the first scientist who made astronomical telescope by
himself in 1609 .
2- Earth is from ………….. planets , while Jupiter is from the ……….. planets
3- The length of Hubble telescope is …………….. .
4- Our galaxy is called …………….. and it has a ………… shape .
5- Places where astronomers work and where …………..are kept in side are
called ……………..
6- Hubble telescope uses ……………. to collect light .
B- Write the scientific term :
1) A celestial system consists of 200 billion stars .
[…………………]
2) The most famous space monitoring telescope .
[…………………]
3) The first satellite that was launched successfully in an orbit around the earth
[…………………]
C- Define :
Telescope………………………………………………………………………
…………………………………………………………………………………
D- Choose the correct answer :
1- Galileo used …………. to make his telescope.
a- mirrors
b- lenses
c- aluminum
2- All the following are from the huge gaseous planets except …………..
a- Venus
b- Neptune
c- Saturn
d- Uranus
3- We can study the stars by looking at them using ……………….
a- telescope
b- microscope
c- naked eyes
26
• Plants can make its own food from raw materials in the environment by a process called
Photosynthesis process
• The raw materials are carbon dioxide from air, water and mineral salts from soil in
presence of sunlight.
• The plant needs little amounts of phosphorus, magnesium, calcium, nitrogen, zinc and
others.
• The plant has two systems: shoot system and root system.
• Plants get water and salts from soil in two steps:
a) Absorption of water and salts from soil through root hair.
b) Transmission of water and salts from root system to shoot system.
Structure of root system:
We have 4 layers:
1) Epidermis layer: The external layer and root hair
extend from its cells.
2) Cortex layer: the last row in cortex is called
Endodermis.
3) Xylem (wood) layer
4) Pith layer (last layer)
Importance (function) of root system:
The root system is subdivided and extended in soil (G.R.F.)
1) To fix the plant in soil.
2) To cover a large area of soil (G.R.F.) to search for salts and water, absorb and rise them
to other plant parts.
Root hair:
• Root hairs extend from the root.
• Structure: lined from inside with a thin layer of cytoplasm
and have a big vacuole.
27
• The age of the root hair doesn't exceed few days (G.R.F.)
- Because the epidermal cells are lost during penetration of soil due resistance of soil
particles
- These cells are replaced continuously.
What makes the root hair appropriate for absorption of water and salts?
1) It has a thin membrane (G.R.F.) to allow penetration of water and salts through it.
2) Root hairs are found in large number (G.R.F.) to increase the area of absorption surface.
3) Root hair secretes a sticky substance (G.R.F.) to help in root penetration through the soil
4) The vacuole is filled with high salt concentration (low water concentration) which helps
in water transmission from soil to inside the root hair by osmosis.
Osmosis:
Transmission of water molecules from high water concentration to low water
concentration through a semi-permeable membrane.
G.R.F.: root hair can absorb water from soil.
- Because the salt concentration inside the vacuole is larger than the salt conc. in the soil.
How water flows through the root system?
• Water passes from soil to inside root hair by osmosis.
• Water moves through root cells till it reaches
endodermis.
• Endodermis regulates water crossing into xylem tissue.
(function of endodermis)
• Inside xylem vessel water rises from root to stem and other plant parts.
Absorption of mineral salts:
Mineral salts passes through cell membrane by selective permeability
Selective permeability:
The cell membrane allows only the salts which the plant needs to pass through
• The plant get the energy needed for selective permeability from respiration process.
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What is meant by transpiration process?
Transpiration process:
It is a process where the plant loses excess water in the form of water vapor through
holes called stomata
• Stomata (stoma) are holes in plant leaves, they widespread on the lower surface of plant
leaves.
• Each stoma is surrounded by two guard cells.
• Function of guard cells: Each cell changes its shape to open and close stoma.
Transpiration process create pressure (pulling force) that helps in water rising to top of
plant.
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Sheet (8)
I- Complete:
1) The plants takes ………..,……….. from the air ,……..…….. from the soil,
with the presence of light , then plant forms its food by the ………....process.
2) Absorbing minerals & water from the soil occurs by …………. in the root.
3) The root systems composed of …………. &………….
4) The root hair extend from the …………. and is lined from inside with a thin
layer of …………..
5) In the plant water passes into tissue of ……….. where the juice is raised to
reach the stem of plant and leaves , then the other …………….
6) The process of allowing some salts to pass according to the plants need is
called ………..….
7) The vital process by which the plant gets rid of water is called …………
II – Write Scientific Term:
1) It fixes the plant in soil and prevent the soil erosion .
[…..…………………]
2) Cells in plant root which regulates water crossing into a xylem tissue .
[…..…………………]
3) The openings in the plant leaves to get rid of water in the form of water
vapor
[…………………….]
4) The two cells which surround the stomata .
[…….………………]
5) A process contributes in water and dissolved substance transmission to
top of the plant.
[……………………]
6) The transfer of water from high concentration area to low concentration
area through semi – permeable membrane .
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[…….………………]
III- Give reason for :
1- The root system in plant is subdivided and extended through soil particles.
…………………………………………………………………..
2- Stomata are very important for plant .
…………………………………………………………………..
3- Root hair has a concentrated solution more than the soil solution.
…………………………………………………………………..
4- The age of root hair doesn't exceed few days.
…………………………………………………………………..
5- The root hair secretes sticky substance.
…………………………………………………………………..
6- The root hairs are of thin walls.
…………………………………………………………………..
IV- What happens if :
1- The root hair doesn’t secrete sticky substance.
…………………………………………………………………………
2- The leaves don’t have stomata.
…………………………………………………………………………
3- The plant doesn’t make photosynthesis
…………………………………………………………………………
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Simple test
1st Question :
A) Complete the following statements:1- ………………………..……… and ………………………. from the dangers 10 Marks
of electricity .
2- …………………… is an example of the first class levers while ………………… is an
example of the second class levers .
3- The fluorescent glass tube contains ………………. gas and a little of ……………….
B) Match from column ( B ) what is suitable for column ( A ) :(A)
1234-
Lever
Electric load
Electric current
Solar eclipse
(B)
a- is a flow of electric charges through a conductor .
b- occurs when the moon is located between sun and
Earth on one straight line .
c- occurs by connecting more than one machine to one
socket .
d- is a rigid bar that rotates around a fixed point .
2nd Question :
A) Write the scientific term:10 Marks
1- The main source of light .
[…………………………..]
2- The materials that don’t allow the flow of electricity through it.[……………………....]
3- A type of solar eclipse is formed in the shadow area of the moon in which the sun
can’t bee seen completely .
[…………………………..]
4- Levers that have the force between the resistance and the fixed point .
[…………………………..]
B ) Correct the underlined words:1- The base of the light bulb has a piece of glass for connection .
2- The annular solar eclipse occurs when the moon lies in the lower orbit from the Earth
in front of the sun .
3- The manual broom is considered as a second class lever .
4- To avoid danger of electricity , we have to insert a metal object in the socket .
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3rd Question :
10 Marks
A) Choose the correct answer:1- The inner tube surface of the fluorescent lamp is covered with ……………. material .
a- neon
b- lead
c- copper
d- phosphoric
2- ……………….. is good conductor of electricity .
a- Iron
b- Glass
c- Wood
d- Plastic
3- If the resistance arm is longer than the force arm , the resistance will be ……….. than
the effort force .
a- smaller
b- larger
c- equals
d- a and c
4- The moon revolves around the Earth in ………………. orbit .
a- circular
b- oval
c- rectangular
d- spherical
B) Give reason for :
1- The second class levers conserve the effort .
………………………………………………………………………………
………………………………………………………………………………
2- It is preferred to connect the lamps at home in parallel .
………………………………………………………………………………
………………………………………………………………………………
C) What is the importance of :
1- Special glasses during observing the solar eclipse .
………………………………………………………………………………
4th Question :
10 Marks
A) Put ( √ ) or ( × ) :-
1- The electric chock happens when the body is a part of an opened electric circuit .(
)
2- The solar eclipse phenomenon doesn’t last more than 14 minutes and 7 seconds .(
)
3- The semi-shadow area is called “umbra” .
(
)
4- The force and the resistance can be equal only in the second class lever .
(
)
B) If the effort force equals 20 Newton and length of its arm is 100 cm . Calculate the
value of the resistance if the length of the resistance arm is 50 cm .
…………………………………………………………………………………………..
…………………………………………………………………………………………..
C) Write the labels :
1
1- …………………………………
2- …………………………………
3- …………………………………
2
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3