RIC-6843 Science Essentials 2 (Ages 11-15)

Science Earth science
Forces and energy Chemistry Biology
Biology
THE LUNGS
When we breathe, our lungs take oxygen from
the air and pass it into our bloodstream. The
oxygen is carried to our cells by our blood.
Our cells:
• use the oxygen to release energy
• make a waste gas called carbon dioxide, which
we breathe out.
This process is called respiration and is a chemical
reaction as new substances are formed—carbon
dioxide and water.
The lungs are protected by the rib cage.
The diaphragm is a dome-shaped muscle that
works with the lungs so we can inhale and exhale.
epiglottis
trachea
bronchioles
capillaries
THE HEART
A network of vessels reaches every part of our
body, carrying blood which takes vital nutrients and
oxygen to each cell. The centre of this system is
the heart, which pumps blood continuously.
arteries – muscular tubes with thick walls that carry
usually oxygenated
blood away from the
heart
veins – muscular tubes
with thinner walls with
valves which carry
usually deoxygenated
blood back to the heart
The heart has four
chambers.
alveoli
Pulmonary
artery
Right
atrium
Right
ventricle
The sun is the source of all energy. Plants convert
light energy via the process of photosynthesis into
chemical energy in their leaves. Plants are ‘producers’
in the food chain.
• Photosynthesis uses light to make food and occurs
in green leaves.
• Plants take in CO 2
and H 2
O.
• The chlorophyll in the leaves changes the CO 2
and H 2
O into O 2
and food. This reaction can be
written as:
visible light energy
carbon dioxide + water
glucose + oxygen
chlorophyll
In plants glucose is converted to:
• starch • protein • cellulose
oesophagus
(food pipe)
Aorta
Left
atrium
Left
ventricle
lung
bronchi
heart
diaphragm
Our body
and plants
PLANTS
Transpiration
Stomata are pores in the leaf. Each stoma allows the carbon dioxide
necessary for photosynthesis to enter, while water evaporates
through each one in transpiration.
Phloem and xylem vessels are
thin tubes that carry liquids
around a plant and are found in
groups called vascular bundles.
Phloem transports the sugar
solution (translocation).
Xylem vessels carry minerals
and water up the plant from the
roots.
The roots anchor the plant and
the root hairs obtain water and
soluble salts.
FOOD
The chemicals in foods are called nutrients and they give us:
• the energy to live
• materials to make new cells for growth, and to repair and replace
damaged or dead cells.
A balance of the fi ve main nutrient groups is required for a healthy
body—carbohydrates, proteins, fats and oils, vitamins, minerals.
Fibre is found in the walls of plant cells and helps with digestion.
Water is essential for our cells to function properly and for the
nutrients to move around our bodies.
The body breaks down carbohydrates to form glucose that is sent
to the cells in the body and used for energy.
DIGESTIVE SYSTEM
The body uses chemicals called
enzymes to break down the food
we eat and absorb its nutrients.
1. Mouth – teeth and saliva break
down food.
2. Epiglottis – fl ap of tissue that
prevents food from entering
windpipe.
3. Oesophagus – carries food to
the stomach
4. Stomach – a muscular bag that
stores and mixes the food.
Gastric juices and hydrochloric
acid assist with protein digestion
and the acid also kills germs
5. Liver – makes bile to break
down fats, controls blood sugar,
destroys poisons
6. Gall bladder – stores bile from
liver used to break up fat
7. Pancreas – produces enzymes to
help digest carbohydrates and proteins
8. Small intestines – food moves
through the 6-m long tube; digestion is completed here, cells in the
walls release mucus and water and nutrients are absorbed
9. Large intestine (colon) – salts, water, vitamins and sugars are absorbed,
undigested food forms faeces.
10. Rectum – stores the faeces which are then pushed out the anus.
5.
6.
7.
10.
3.
essentials
Plant diagram
main root
lateral root
root hairs
8.
2.
1.
4.
9.
xylem
phloem
Earth science
Weathering is the process where larger rocks are broken
down into smaller rocks. This can happen by:
• physical means – temperature changes, wind, force of the
sea.
• chemical means – chemicals dissolved in rain and in the
air react with rock surfaces.
Erosion is caused by wind, running water, the sea and
glaciers.
The weathered rock is moved by erosion and settles as
sediment. It settles on river beds, the land and in the seas.
When acid rain reacts with rocks, they become weaker and
can crumble more easily.
Rocks
Igneous rocks are formed from the cooling of magma and
can form above or below the surface.
Crystals can appear in igneous rocks. Their size is
determined by the rate at which they cooled.
Granite is a type of igneous rock. It is a white, pink or grey
rock with fl ecks of glassy or black minerals.
VOLCANOES AND EARTHQUAKES
Volcanoes
When molten rock
(magma) from inside the
Earth erupts through a
weakness in the Earth’s
crust, a volcano is formed.
Lava, ash, dust and gases
escape through the crater.
After a series of eruptions,
a cone-shaped mountain is
formed.
Lava is fl owing out of
certain places in the ocean
fl oors all the time. Midoceanic
ridges are formed.
Types of volcanoes:
• active • extinct
• dormant (sleeping)
The Earth
About 30% of the Earth’s
surface is dry land, the rest
is mostly salt water, known
as the oceans, that range
from a few metres to 10
km deep.
Under the water is a solid
crust that is between 6 km
and 70 km thick.
Plate tectonics
It is believed that the
Earth’s crust is divided into
a number of plates that
move on layers of molten
rock in the upper mantle.
Earthquakes
The Earth
ROCKS
When two plates of the
Earth’s crust move, tremors
and earthquakes occur. Great
pressure causes them to slide
past or push against each other
(and sometimes move apart).
A subduction zone occurs where
oceanic crust pushes against
the less dense continental crust,
forming a trench.
©R.I.C. Publications
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oceanic
crust
lithosphere
trench
volcanic
arc
continental
crust
lithosphere
aesthenosphere
Faults and folding
When two continents on colliding
plates move against each other,
parts of the crust are pushed
upwards, making mountains.
anticline – upwards fold
syncline – downward fold
(The Himalayas are still rising.)
A fault is when movement occurs
along a crack in the rocks.
horst – block of Earth pushed
upwards
slip fault – sideways movement
along a fault
MINING
Millions of years ago, plants and animals died and were
buried under mud and sand, transforming into coal,
oil and natural gas. The once living materials can be
extracted from the ground and the stored energy
converted to power.
Coal
• thick layers of rotting plant material were
compressed to become peat
• with heat, brown coal was formed
• more moisture was removed due to compression
and black coal was produced
• open-cut mining can be used when the coal is close
to the surface and underground mining (which is
more costly) when it is further underground
Oil and gas
• formed from the remains of plants and sea animals
• buried under the oceans and compressed by water
• chemical reaction changed them into oil and natural
gas
• oil is used as fuels—petrol, diesel, kerosene
Renewable resources – resources that can be replaced
Non-renewable resources – only a limited supply and
can not be replaced
Mineral resources
essentials
The ocean fl oor is covered with basalt, an igneous rock that
formed when lava cooled quickly.
Sedimentary rocks are formed when sediments of
weathered rock are deposited via erosion in layers. These
layers harden with pressure, heat and evaporation over time.
Limestone is a sedimentary rock formed from shellfi sh and
corals that were deposited and the hard parts (calcium
carbonate) remained. Over time, the calcium carbonate
joins together and hardens.
Metamorphic rocks were once sedimentary rocks below
the Earth’s surface, but were subjected to high temperature
and pressure, changing the rock’s appearance. This process is
called metamorphism.
Fossils
Fossils are formed when a plant or animal dies and is
preserved in sediment before it decays. The remains may
leave an imprint in the rock which can be studied by
palaeontologists.
Fossils provide clues about primitive life.
Mineral resources can be detected by:
• satellites and aircraft
• testing surrounding water and sediments in lakes.
The non-metals oxygen (46%) and silicon (27%) make
up the largest part of the Earth’s crust. Metals are rare
and are usually combined with non-metals in materials.
After a mineral ore has been removed from the
ground it must undergo several processes to arrive at
the metal:
1. Concentration 2. Reduction (smelting)
3. Purifi cation

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