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Work through each slide in this Padlet.

Watch each video.

Follow each link.

Complete the activities.

Play the games.

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6.ESS2.1 Gather evidence to justify that oceanic convection currents are caused by the sun’s transfer of heat energy and differences in salt concentration leading to global water movement.

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Click on the Vocabulary Google Slide Show and study Unit 7 vocabulary. Pay close attention to the highlighted keywords and pictures.

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Unit 7 Vocabulary Circulation in Earth’s Air and Oceans

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What are the three types of heat? Use the following three slides to find out! Click the links to read, watch videos, and work through activities about heat transfer.

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Click the link and read about the three types of heat transfer.

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Section B. Energy Transfer

An Example of How Doing Work Transfers Energy from One Object to Another
Suppose that a person (the agent) exerts a force on a wheelbarrow (the object) that is initially at rest, causing it to move over a certain distance. Recall that the work done on the wheelbarrow by the person is equal to the product of the person's force multiplied by the distance traveled by the wheelbarrow. Notice that when the force is exerted on the wheelbarrow, there's a change in its motion. Its kinetic energy increases. But where did the wheelbarrow get its kinetic energy? It came from the person exerting the force, who used chemical energy stored in the food they ate to move the wheelbarrow. In other words, when the person did work on the wheelbarrow, they transferred a certain amount of chemical energy to the wheelbarrow, causing it to move. As a result, the person's store of chemical energy decreases and the wheelbarrow's kinetic energy increases.

2. Heat Transfer

Heat is the transfer of energy from a warmer object to a cooler object. For example, a lighted match (higher temperature object) will transfer heat to a large pan filled with lukewarm water (lower temperature object). Note that the actual amount of thermal energy each object has doesn't matter, as the pan of lukewarm water might have more thermal energy than the match. What is needed for heat transfer to take place is a difference in temperature between two objects. Without this difference, no heat transfer can take place.

Heat can be transferred in three ways: by conduction, by convection, and by radiation.

1. Conduction is the transfer of energy from one molecule to another by direct contact. This transfer occurs when molecules hit against each other, similar to a game of pool where one moving ball strikes another, causing the second to move. Conduction takes place in solids, liquids, and gases, but works best in materials that have simple molecules that are located close to each other. For example, metal is a better conductor than wood or plastic.

2. Convection is the movement of heat by a fluid such as water or air. The fluid (liquid or gas) moves from one location to another, transferring heat along with it. This movement of a mass of heated water or air is called a current.

3. Radiation is the transfer of heat by electromagnetic waves. When you stand in the sun, you are warmed by the electromagnetic waves, mainly infrared radiation (and to a lesser extent, visible light), that travels from the sun to Earth. In addition to the sun, light bulbs, irons, and toasters also transfer heat via radiation. Note that, unlike conduction or convection, heat transfer by radiation does not need any matter to help with the transfer.

You can detect evidence of heat transfer. You might see the air shimmering over a radiator ( convection), put your hand on a warm spoon that's been sitting in a hot bowl of soup ( conduction), or notice that the sun shine feels warm on your skin ( radiation). If you need evidence of thermal energy or heat in your life, just feel your arm. Your body generates heat 24 hours a day! (Taken from KEEP Energy Education Activity Guide " Exploring Heat ").

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Unit 2 - Section B - University of Wisconsin-Stevens Point

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Unit 2: Energy Rules! Section B. Energy Transfer 1. Doing Work Energy can be transferred from one object to another by doing work. To do work requires that an agent...

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Convection vs Conduction vs Radiation for Rad Techs

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Any matter which is made up of atoms and molecules has the ability to transfer heat. The atoms are in different types of motion at any time. The motion of molecules and atoms is responsible for heat or thermal energy and every matter has this thermal energy. The more the motion of molecules, more will be the heat energy. However, talking about heat transfer, it is nothing but the process of transfer of heat from a high-temperature body to a low temperature one.

What is Heat Transfer?

According to thermodynamic systems, heat transfer is defined as

"The movement of heat across the border of the system due to a difference in temperature between the system and its surroundings."

Interestingly, the difference in temperature is said to be a 'potential' that causes the transfer of heat from one point to another.

How is Heat Transferred?

Heat can travel from one place to another in several ways . The different modes of heat transfer include:

Meanwhile, if the temperature difference exists between the two systems, heat will find a way to transfer from the higher to the lower system.

What is Conduction?

Conduction is defined as

The process of transmission of energy from one particle of the medium to another with the particles being in direct contact with each other.

An area of higher kinetic energy transfers thermal energy towards the lower kinetic energy area. High-speed particles clash with particles moving at a slow speed, as a result, slow speed particles increase their kinetic energy. This is a typical form of heat transfer and takes place through physical contact. Conduction is also known as thermal conduction or heat conduction.

Conduction Equation
The rate of conduction can be calculated by the following equation:
Where,

Q is the transfer of heat per unit time

K is the thermal conductivity of the body

A is the area of heat transfer

Thot is the temperature of the hot region

Tcold is the temperature of the cold region

d is the thickness of the body

The coefficient of thermal conductivity shows that a metal body conducts heat better when it comes to conduction.

Conduction Examples

Following are the examples of conduction:

Ironing of clothes is an example of conduction where the heat is conducted from the iron to the clothes.

Heat is transferred from hands to ice cube resulting in the melting of an ice cube when held in hands.

Heat conduction through the sand at the beaches. This can be experienced during summers. Sand is a good conductor of heat.

What is Convection?

Convection is defined as

The movement of fluid molecules from higher temperature regions to lower temperature regions.

Convection Equation

As the temperature of the liquid increases, the liquid's volume also has to increase by the same factor and this effect is known as displacement. The equation to calculate the rate of convection is as follows:

Where,

Q is the heat transferred per unit time

hc is the coefficient of convective heat transfer

A is the area of heat transfer

Ts is the surface temperature

Tf is the fluid temperature

Convection Examples

Examples of convection include:

Boiling of water, that is molecules that are denser move at the bottom while the molecules which are less dense move upwards resulting in the circular motion of the molecules so that water gets heated.

Warm water around the equator moves towards the poles while cooler water at the poles moves towards the equator.

Blood circulation in warm-blooded animals takes place with the help of convection, thereby regulating the body temperature.

Learn more about Convection

What is Radiation?

Radiant heat is present in some or other form in our daily lives. Thermal radiations are referred to as radiant heat. Thermal radiation is generated by the emission of electromagnetic waves . These waves carry away the energy from the emitting body. Radiation takes place through a vacuum or transparent medium which can be either solid or liquid. Thermal radiation is the result of the random motion of molecules in matter. The movement of charged electrons and protons is responsible for the emission of electromagnetic radiation. Let us know more about radiation heat transfer.

Radiation heat transfer is measured by a device known as thermocouple. A thermocouple is used for measuring the temperature. In this device sometimes, error takes place while measuring the temperature through radiation heat transfer.

Radiation Equation

As temperature rises, the wavelength in the spectra of the radiation emitted decreases and shorter wavelengths radiations are emitted. Thermal radiation can be calculated by Stefan-Boltzmann law:

Where,

P is the net power of radiation

A is the area of radiation

Tr is the radiator temperature

Tc is the surrounding temperature

e is emissivity and σ is Stefan's constant (σ = 5.67 × 10⁻⁸Wm⁻²K⁻⁴

Radiation Example

Following are the examples of radiation:

Microwave radiation emitted in the oven is an example of radiation.

UV rays coming from the sun is an example of radiation.

The release of alpha particles during the decaying of Uranium-238 into Thorium-234 is an example of radiation.

Unit of Heat Transfer
To know more about heat transfer in detail, click on the video below.
Frequently Asked Questions - FAQs

What are the different modes of heat transfer?

Give an example of radiation.

Example: UV rays coming from the sun.
Microwave radiation emitted in the oven.

How is electromagnetic radiation emitted?

Electromagnetic radiations are emitted through the movement of charged electrons and protons.

What is the movement of molecules in fluids from higher temperature regions to lower temperature regions known as?

It is known as convection.

Put your understanding of this concept to test by answering a few MCQs. Click 'Start Quiz' to begin!

Select the correct answer and click on the "Finish" button
Check your score and answers at the end of the quiz

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What Is Heat Transfer? Conduction, Convection, Radiation and FAQs

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Heat transfer is defined as the process in which the molecules are moved from the region of higher temperature to lower temperature. Conduction, convection, and radiation are the types of heat transfer.

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Click the link and play Kahoot! to study your vocabulary.

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https://create.kahoot.it/details/9ceb34c5-b085-4dda-8fe0-d1deae75d32c

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The sun heats the Earth by electromagnetic radiation of its rays. However, it does not heat every part of the Earth in the same way. This uneven heating of Earth causes some places to be significantly warmer than other places. These differences in temperatures at different places on Earth cause convection currents of hot air rising and cold air sinking. Click the video to learn more.

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Ocean & Atmosphere - 3-Cell Atmospheric Circulation, Part 1

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Global Conveyer Belt

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Ocean water is always in a state of motion. There are majorly three forms of ocean water movements. In this article, you can read all about the movement of the ocean water for the geography segment.

Ocean Water Movements

The movement of ocean water is influenced by its physical characteristics (temperature, salinity and density) and the external forces (sun, moon and winds). The movement of ocean water takes place in three ways-

Waves and ocean currents are horizontal movements of ocean waters while the tides are due to vertical movement of the ocean waters.

Waves are a kind of horizontal movement of ocean water.
Characteristics of Waves

1. Wave crest - The upper or highest part of a wave is called the crest.

2. Wave trough- The lowest part of a wave is called the trough.

3. Wave height - It is the vertical distance from the bottom of a trough to the top of a crest of a wave.

4. Wavelength - It is the horizontal distance between two successive crests or troughs.

5. Wave amplitude - It is one-half of the wave height.

6. Wave period - It is the time interval between two successive wave crests or troughs as they pass a fixed point.

7. Wave frequency - It is the number of waves passing a given point during one second time interval.

8. Wave speed - It is the rate at which the wave moves through the water and is measured in knots.

Tides are the periodical rise and fall of the ocean levels once or twice a day mainly due to the gravitational forces exerted by the sun, the moon and the rotation of the earth.

Tides occur due to the vertical movement of the ocean waters and are different from the movement of water caused by meteorological effects like winds and atmospheric pressure changes. Such water movements are called surges and are not regular like tides.

Moon's gravitational pull is the major cause of the occurrence of tides, as it is more effective than that of the sun. The sun's gravitational pull and the centrifugal force due to the rotation of the earth are the other forces that act along with the moon's gravitational pull.

The gravitational pull and the centrifugal force create two major tidal bulges on the earth. On the side of the earth facing the moon, a tidal bulge is created because the attractive force of the moon is greater than the centrifugal force. On the opposite side of the earth, the attractive force is less as it is farther away from the moon, and the centrifugal force is dominant. It results in a second bulge away from the moon. The tide generating force is the difference between the gravitation of the moon and the centrifugal force.

When the tide is channelled between islands or into bays and estuaries, they are called tidal currents.

The highest tides in the world occur in the Bay of Fundy in Nova Scotia, Canada.

Flow tide and ebb tide
Flow tide/High tide - The time between the low tide and high tide, when the tide is rising is called the flow or flood tide. It is the rising tide.

Ebb tide/low tide - The time between the high tide and low tide, when the tide is falling is called the ebb. It is the receding tide.

Types of Tides

Based on their frequency of occurrence -

Semi-diurnal - The most common tidal pattern with two high tides and two low tides each day. The successive high or low tides are approximately of the same height.

Diurnal tide - Only one high tide and one low tide each day. The successive high or low tides are approximately of the same height.

Mixed tide - Tides varying in height are known as mixed tides. These generally occur along the west coast of North America and on many islands of the Pacific Ocean.

Based on the sun, the moon and the earth's positions -

Spring tide - When the sun, the moon and the earth are in a straight line, the height of the tide will be higher than normal and are called spring tides. Spring tides occur twice a month - one on the full moon and the other on the new moon.

Neap tides - When the sun and the moon are positioned at right angles to each other, the height of the tide will be lower than the normal and are called neap tides. This happens normally after seven days of a spring tide. The gravitational forces of the sun and the moon tend to counteract each other. Neap tides also occur twice a month (during the first quarter moon and the last quarter moon).

Magnitude of Tides
Ocean Currents

Ocean currents are just like a river flowing in an ocean. A large volume of water moving in a fairly defined direction over great distances is called an ocean current.

The ocean currents are produced due to the earth's rotation - Coriolis Force (Coriolis force causes the water to move to the right in the northern hemisphere and to the left in the southern hemisphere), density differences in ocean waters due to differences in temperature and salinity, gravity and wind.
Gyre, Drift and Stream
Gyre - A gyre is any large system of circulating ocean currents, particularly involved with large wind movements. They are caused by the coriolis force.

Drift - When the ocean water moves forward under the influence of prevailing wind, it is called a drift. The term drift is also used to refer to the speed of an ocean current. It is measured in terms of knots (kn). Most currents have speeds less than or equal to 5 knots (1knot =1.852 km per hour).

Stream - Streams are larger masses of water moving in a definite direction and have much greater velocity than the drifts. For example, Gulf Stream.
Types of ocean currents
Based on the temperature -

Surface currents - These constitute about 10% of all the water in the ocean. These waters occupy the upper 400m of an ocean. These currents are driven due to the blowing wind.

Deep water currents - These constitute about 90% of the total ocean water. These waters move around the ocean basins due to variation in the density and gravity.
Know more about ocean currents in the linked article. Ocean Currents of the Pacific Ocean
Major Ocean Currents

The oceanic circulation transports heat from one latitude belt to another in a manner similar to the heat transported by the general circulation of the atmosphere. The warm waters of the lower latitudes move polewards while the cold waters of the Arctic and Antarctic circles move towards warmer waters in tropical and equatorial regions.

1. North Equatorial current - It is a warm current. It originates from RevillaGigedo island-west of Mexico and flows towards Philippines island.

2. South Equatorial current - It is a warm current which originates due to the action of trade winds from east to west. It is stronger than the North Equatorial current.

3. Kuroshio current (Black tide) - It is a warm current which flows in the north-easterly direction up to 30° latitude. It meets the Oyashio cold current off the Kuril islands. It is also called Japan current.

4. Oyashio current (Parental tide) - It is a cold current which originates from Bering Strait and flows southwards. It meets Kuroshio warm current and Aleutian current.

5. Californian current - It is a cold current which flows towards south along the west coast of the U.S.A. In the region of trade winds, it gets deflected to the right and joins the equatorial current.

6. Peru current - Also called Humboldt current as Alexander Von Humboldt noted the details of the Peru current. It is a cold current which flows along the west coast of South America towards the north.

7. West Wind Drift - It is a cold current. It is an easterly moving drift in the Pacific Ocean extending from Tasmania to the South American coast. It splits into two branches - one moves south around Cape Horn into the Atlantic Ocean and the other one moves northwards along the Peruvian coast and joins the Peru current.

Ocean Currents of the Atlantic Ocean -

1. North Equatorial current - It is a warm current which flows from east to the west. On reaching the east coast of South America it splits into two branches - one branch called Antilles current moves along the coast of the West Indies and the other branch is diverted into the Caribbean Sea.

2. South Equatorial current - It is a warm current which flows between the coast of Africa and South America. It is caused by the action of trade winds and is stronger than the north equatorial current.

3. Gulf Stream - It was discovered by Ponce de Leon in 1513. It is a warm current which starts from the Gulf of Mexico. It joins the Labrador cold current near Newfoundland, Canada after passing through the Strait of Florida.

4. Canaries current - It is a cold current which flows along the western coast of North Africa between Madeira and Cape Verde. It merges with the north equatorial current.

5. Labrador current - It is a cold current and brings cold waters from the polar zone. It moves along the coast of Greenland.

6. Benguela current - It is a cold current which flows northward along the western coast of Africa. It brings cold water from sub-Antarctic surface water. It merges with the south equatorial current.

Ocean Currents of the Indian Ocean -

The south Indian gyre is formed by the south equatorial current, Madagascar current, west wind drift and west Australian current. To the north of the equator, the currents in the Arabian sea and Bay of Bengal flow in the clockwise direction as southwest monsoon drift and in the anti-clockwise direction as northeast monsoon drift due to influence of monsoon winds.
Movements of Ocean Water:- Download PDF Here
Ocean Currents of the Southern Ocean -

The continent of Antarctica is surrounded by the Southern Ocean. The Pacific, the Atlantic and the Indian oceans merge into this circum-global zone of water to their south. The movement of water in the southern ocean is generally west-east circum polar drift caused under the influence of northwesterly winds. This flow sends offshoots to the three major oceans to its north. The Peru or Humboldt current in the Pacific ocean, the Falkland current and the Benguela current in the Atlantic ocean and the west Australian current in the Indian ocean receive a part of their cold waters from the Southern Ocean.

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Movements of Ocean Water [Geography Notes for UPSC]

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Movements of Ocean Water - Waves, Tides and Ocean Currents. Click here for crisp UPSC Notes on Geography, also download PDF.

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What else does the uneven heating of Earth affect?

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What else does the uneven heating of Earth affect?

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Global Winds

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Click and explore the global winds on Earth.

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earth :: a global map of wind, weather, and ocean conditions

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See current wind, weather, ocean, and pollution conditions, as forecast by supercomputers, on an interactive animated map. Updated every three hours.

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Global winds also influence ocean currents

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Global winds also influence ocean currents

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The uneven heating of Earth and the spinning rotation on Earth's axis causes different bands of air in the atmosphere. These wind belts also move in convection patterns, like the ocean currents. Hot air rises and cold air sinks, causing convection patterns in the atmosphere.

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Our weather is affected by the Jet Stream!

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Jet Stream | Wind Maps | Weather Underground