Why is the color of the sea Why is the color of the sea blue?blue?The color of the sea depends on the The color of the sea depends on the

reflection of light. The color of the reflection of light. The color of the sky is reflected on the sea so it can sky is reflected on the sea so it can be deep blue, turquoise, light blue, be deep blue, turquoise, light blue, grey, depending on the weather. Of grey, depending on the weather. Of course whatever is in the sea can course whatever is in the sea can also affect its color like seaweed, also affect its color like seaweed, countless floating particles, bacteria countless floating particles, bacteria e.t.c. Also the depth of the sea as e.t.c. Also the depth of the sea as well as the sand play a role in what well as the sand play a role in what color we see. color we see.

Why is the sea water salty?Why is the sea water salty?As water crosses and corrodes land, As water crosses and corrodes land,

salt as well as other minerals get salt as well as other minerals get carried away with it in rivers at first carried away with it in rivers at first and then in the sea. Salt remains in and then in the sea. Salt remains in the sea as it can’t go anywhere else. the sea as it can’t go anywhere else. As sea water evaporates most of the As sea water evaporates most of the salt remains in the sea so it becomes salt remains in the sea so it becomes saltier and saltier every time. On saltier and saltier every time. On average each liter of sea water average each liter of sea water contains 35gr of salt. contains 35gr of salt.

How are waves created?How are waves created?The most common cause of waves is The most common cause of waves is

the wind. “Wrinkles” of different the wind. “Wrinkles” of different shape are created on the surface of shape are created on the surface of the sea and as the wind gets the sea and as the wind gets stronger they are altered. When the stronger they are altered. When the wind stops waves take a specific wind stops waves take a specific form with a certain height, length form with a certain height, length and duration. The sea water is not and duration. The sea water is not moved, just the shape of the water moved, just the shape of the water surface changes. surface changes.

What is the sand and how do What is the sand and how do we use it?we use it?Every accumulation of small specks of Every accumulation of small specks of

rocks is considered as sand. The rocks is considered as sand. The specks need to have a diameter specks need to have a diameter smaller than 6mm. Depending on the smaller than 6mm. Depending on the diameter there are different types of diameter there are different types of sand ( “fat”, “medium”, “thin”, sand ( “fat”, “medium”, “thin”, e.t.c. ). e.t.c. ).

We use sand in construction to make We use sand in construction to make cement. We also use sand to make cement. We also use sand to make glass. glass.

What is a tsunami and how is it What is a tsunami and how is it created? created? Tsunamis are huge waves in the sea. Tsunamis are huge waves in the sea.

They are actually the result of an They are actually the result of an earthquake. As the plates move earthquake. As the plates move towards each other there is a lot of towards each other there is a lot of pressure. This results in an pressure. This results in an earthquake and all of this energy is earthquake and all of this energy is released in the sea so huge waves released in the sea so huge waves are formed. The biggest tsunami was are formed. The biggest tsunami was 35m high, in Indonesia. It had been 35m high, in Indonesia. It had been traveling towards the land for 7 days!traveling towards the land for 7 days!

What is the plankton?What is the plankton?It’s name comes from an ancient It’s name comes from an ancient

Greek word meaning “wanderer”. It Greek word meaning “wanderer”. It is a diverse group of organisms living is a diverse group of organisms living in the water like bacteria, algae, in the water like bacteria, algae, protozoa e.t.c. It typically floats with protozoa e.t.c. It typically floats with ocean currents. Also it is divided in ocean currents. Also it is divided in different groups like Phytoplankton different groups like Phytoplankton or Zooplankton but also according to or Zooplankton but also according to its size. It is a source of food mainly its size. It is a source of food mainly for fish but it can also produce for fish but it can also produce oxygen in water through the process oxygen in water through the process of photosynthesis. of photosynthesis.

What does the depth of the sea What does the depth of the sea depend on and what are the deepest depend on and what are the deepest points in the Mediterranean and points in the Mediterranean and Worldwide?Worldwide?The depth of the sea depends mainly on the The depth of the sea depends mainly on the

morphology of the sea bottom. morphology of the sea bottom. The deepest point in the Mediterranean is The deepest point in the Mediterranean is

5.267m, 35 miles Southwest of the Cape 5.267m, 35 miles Southwest of the Cape Tainaron. Tainaron.

The deepest point in the Pacific Ocean is The deepest point in the Pacific Ocean is 10.870m Northwest of Japan ( Mariana 10.870m Northwest of Japan ( Mariana Trench ). Trench ).

The deepest point of the Atlantic Ocean is The deepest point of the Atlantic Ocean is 9.214m North of Puerto Rico Trench. 9.214m North of Puerto Rico Trench.

Which Mediterranean species Which Mediterranean species are threatened with extinction?are threatened with extinction?There are a lot of sea animals There are a lot of sea animals

threatened with extinction in the threatened with extinction in the Mediterranean. Some of them are the Mediterranean. Some of them are the dolphins, the Caretta caretta sea dolphins, the Caretta caretta sea turtle, the Monachus monachus seal, turtle, the Monachus monachus seal, the red coral, the sponges, the the red coral, the sponges, the grouper, the Audouin's gull, the grouper, the Audouin's gull, the sperm whalesperm whale, , the Dalmatian pelican the Dalmatian pelican and many more. and many more.

What are the seaweed?What are the seaweed?

Seaweed are water plants. They exist Seaweed are water plants. They exist both in salty and sweet waters. They both in salty and sweet waters. They are long, usually with roots or they are long, usually with roots or they can also float in water. There are can also float in water. There are different kinds of seaweed, green different kinds of seaweed, green ( full of chlorophyll ), grey, red and so ( full of chlorophyll ), grey, red and so on. Seaweed can be found in on. Seaweed can be found in different depths of the sea. different depths of the sea.

What are pearls and how are What are pearls and how are they created?they created?A pearl is a usually round shaped hard A pearl is a usually round shaped hard

substance, found inside an oyster. substance, found inside an oyster. The oysters don’t like intruders, so The oysters don’t like intruders, so when something gets inside them (a when something gets inside them (a pebble, sand, parasites ) they start pebble, sand, parasites ) they start covering it with a hard crystal covering it with a hard crystal substance so as to send the intruder substance so as to send the intruder away! This intruder wrapped in that away! This intruder wrapped in that substance is the pearl! substance is the pearl!

What are the benefits of the What are the benefits of the sea?sea?The sea has a lot of beneficial The sea has a lot of beneficial

elements. Some of them are iodine, elements. Some of them are iodine, calcium, vitamins, amino acids and calcium, vitamins, amino acids and more. They are good for our health. more. They are good for our health.

The sea also gives us fish. It helps the The sea also gives us fish. It helps the economy of a country and last but economy of a country and last but not least it offers us relaxation and not least it offers us relaxation and fun in the summer time!fun in the summer time!

How much of the Earth’s How much of the Earth’s surface does the sea cover?surface does the sea cover?

The Earth is a very “watery” planet!The Earth is a very “watery” planet!71% of the Earth is covered by water. 71% of the Earth is covered by water. Oceans hold about 96.5% of all Earth’s Oceans hold about 96.5% of all Earth’s

water. water.

Are there animals that live in Are there animals that live in the sand at the bottom of the the sand at the bottom of the sea?sea?There are a lot of animals living in There are a lot of animals living in

the sand at the bottom of the the sand at the bottom of the sea. They are usually found in sea. They are usually found in the mud or the sand and rocks. the mud or the sand and rocks.

Sand dabs live there, sea worms, Sand dabs live there, sea worms, snake fish, jaw fish, sand crabs snake fish, jaw fish, sand crabs and a lot more!and a lot more!

What is the biggest creature of What is the biggest creature of the sea?the sea?Blue whales are the biggest creatures Blue whales are the biggest creatures

to have ever lived on Earth. The to have ever lived on Earth. The largest one to be measured was largest one to be measured was 171.000 kgs and 27m long! The 171.000 kgs and 27m long! The longest one was 33m long!longest one was 33m long!

Just imagine its heart is the size of a Just imagine its heart is the size of a car!!car!!

Are there sharks in the Cretan Are there sharks in the Cretan Sea?Sea?There are 457 species of sharks There are 457 species of sharks

and 47 of them can be found in and 47 of them can be found in the Mediterranean too. Some of the Mediterranean too. Some of them have been spotted South of them have been spotted South of Crete. Crete.

What are shells made of? What are shells made of?

A sea shell is the hard part on an A sea shell is the hard part on an animal that lives in the sea. It is animal that lives in the sea. It is part of their body. Shells are part of their body. Shells are made of calcium carbonate, made of calcium carbonate, proteins and minerals. Animals proteins and minerals. Animals “build” their “houses” with these “build” their “houses” with these elements and as they grow so do elements and as they grow so do their shells!their shells!

How do boats and ships float? How do boats and ships float? The science behind floating was first studied The science behind floating was first studied

by an ancient Greek scientist called by an ancient Greek scientist called Archimedes. He found that when an object Archimedes. He found that when an object is placed in water, it pushes enough water is placed in water, it pushes enough water out of the way to make room for itself. out of the way to make room for itself. There are two forces when an object There are two forces when an object enters water: gravity ( pulling it down ) enters water: gravity ( pulling it down ) and buoyancy ( pulling it up ). If the force and buoyancy ( pulling it up ). If the force of gravity is less than the force of of gravity is less than the force of buoyancy ( so if the object weighs less buoyancy ( so if the object weighs less than the water it pushes “out” ) it will than the water it pushes “out” ) it will float. float.

Why do we like the sea?Why do we like the sea?Most people like the sea for Most people like the sea for

different reasons. Maybe they like different reasons. Maybe they like the salty smell or swimming, the salty smell or swimming, maybe the feeling of sand on their maybe the feeling of sand on their feet. Some like to fish others just feet. Some like to fish others just look at the sea and relax. So look at the sea and relax. So maybe we like the sea because it maybe we like the sea because it makes us think of things we like!makes us think of things we like!

Why do people throw garbage Why do people throw garbage in the sea?in the sea?A lot of industries and people throw A lot of industries and people throw

their garbage in the sea. They do their garbage in the sea. They do that because they don’t care about that because they don’t care about the environment and they think the the environment and they think the damage is not big. Even if we don’t damage is not big. Even if we don’t see the garbage it’s still there and see the garbage it’s still there and they will come back to us one day!they will come back to us one day!

Why are there animals in the Why are there animals in the sea? sea? There are different environments There are different environments

to live on land and in the sea. to live on land and in the sea. Some animals can not breathe Some animals can not breathe and live outside the water so and live outside the water so they live in the sea. The same they live in the sea. The same goes for the animals on land, goes for the animals on land, they can not breathe and live in they can not breathe and live in water. water.