The document discusses thermal energy transfer through conduction, convection and radiation. It provides examples of these modes of transfer and assessment questions to test understanding. Key points covered include:
- Conduction occurs through direct contact of particles, convection through fluid movement, and radiation through electromagnetic waves.
- Materials like metals conduct well while plastics and wood conduct poorly. Convection sets up currents to transfer thermal energy in fluids.
- Designs should maximize conduction and convection for efficient heating, like placing heating elements at the bottom of tanks to induce convection currents. Insulation reduces unwanted conduction and radiation.
This PowerPoint is one small part of the Geology Topics unit from www.sciencepowerpoint.com. This unit consists of a five part 6000+ slide PowerPoint roadmap, 14 page bundled homework package, modified homework, detailed answer keys, 12 pages of unit notes for students who may require assistance, follow along worksheets, and many review games. The homework and lesson notes chronologically follow the PowerPoint slideshow. The answer keys and unit notes are great for support professionals. The activities and discussion questions in the slideshow are meaningful. The PowerPoint includes built-in instructions, visuals, and review questions. Also included are critical class notes (color coded red), project ideas, video links, and review games. This unit also includes four PowerPoint review games (110+ slides each with Answers), 38+ video links, lab handouts, activity sheets, rubrics, materials list, templates, guides, 6 PowerPoint review Game, and much more. Also included is a 190 slide first day of school PowerPoint presentation.
Areas of Focus within The Geology Topics Unit: -Plate Tectonics, Evidence for Plate Tectonics, Pangea, Energy Waves, Layers of the Earth, Heat Transfer, Types of Crust, Plate Boundaries, Hot Spots, Volcanoes, Positives and Negatives of Volcanoes, Types of Volcanoes, Parts of a Volcano, Magma, Types of Lava, Viscosity, Earthquakes, Faults, Folds, Seismograph, Richter Scale, Seismograph, Tsunami's, Rocks, Minerals, Crystals, Uses of Minerals, Types of Crystals, Physical Properties of Minerals, Rock Cycle, Common Igneous Rocks, Common Sedimentary Rocks, Common Metamorphic Rocks.
This unit aligns with the Next Generation Science Standards and with Common Core Standards for ELA and Literacy for Science and Technical Subjects. See preview for more information
If you have any questions please feel free to contact me. Thanks again and best wishes. Sincerely, Ryan Murphy M.Ed www.sciencepowerpoint@gmail.com
Newtons law of cooling, basics of thermodynamicsMUHAMMEDJESWIN
basic idea of some theories in thermodynamics, newton's law of cooling, critical thickness of insulation, Kirchhoff's law of thermal radiation
helpful for building services subject for architecture courses
This PowerPoint is one small part of the Geology Topics unit from www.sciencepowerpoint.com. This unit consists of a five part 6000+ slide PowerPoint roadmap, 14 page bundled homework package, modified homework, detailed answer keys, 12 pages of unit notes for students who may require assistance, follow along worksheets, and many review games. The homework and lesson notes chronologically follow the PowerPoint slideshow. The answer keys and unit notes are great for support professionals. The activities and discussion questions in the slideshow are meaningful. The PowerPoint includes built-in instructions, visuals, and review questions. Also included are critical class notes (color coded red), project ideas, video links, and review games. This unit also includes four PowerPoint review games (110+ slides each with Answers), 38+ video links, lab handouts, activity sheets, rubrics, materials list, templates, guides, 6 PowerPoint review Game, and much more. Also included is a 190 slide first day of school PowerPoint presentation.
Areas of Focus within The Geology Topics Unit: -Plate Tectonics, Evidence for Plate Tectonics, Pangea, Energy Waves, Layers of the Earth, Heat Transfer, Types of Crust, Plate Boundaries, Hot Spots, Volcanoes, Positives and Negatives of Volcanoes, Types of Volcanoes, Parts of a Volcano, Magma, Types of Lava, Viscosity, Earthquakes, Faults, Folds, Seismograph, Richter Scale, Seismograph, Tsunami's, Rocks, Minerals, Crystals, Uses of Minerals, Types of Crystals, Physical Properties of Minerals, Rock Cycle, Common Igneous Rocks, Common Sedimentary Rocks, Common Metamorphic Rocks.
This unit aligns with the Next Generation Science Standards and with Common Core Standards for ELA and Literacy for Science and Technical Subjects. See preview for more information
If you have any questions please feel free to contact me. Thanks again and best wishes. Sincerely, Ryan Murphy M.Ed www.sciencepowerpoint@gmail.com
Newtons law of cooling, basics of thermodynamicsMUHAMMEDJESWIN
basic idea of some theories in thermodynamics, newton's law of cooling, critical thickness of insulation, Kirchhoff's law of thermal radiation
helpful for building services subject for architecture courses
A Brief History of Steel & The Mysterious EutecticKen Newell
The second agricultural revolution coincided with the Industrial Revolution; it was a revolution that would move agriculture beyond subsistence to generate the kinds of surpluses needed to feed thousands of people working in factories instead of in agricultural fields. Bessemer’s invention of cheap steel was the cornerstone of both revolutions.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
MATATAG CURRICULUM: ASSESSING THE READINESS OF ELEM. PUBLIC SCHOOL TEACHERS I...NelTorrente
In this research, it concludes that while the readiness of teachers in Caloocan City to implement the MATATAG Curriculum is generally positive, targeted efforts in professional development, resource distribution, support networks, and comprehensive preparation can address the existing gaps and ensure successful curriculum implementation.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
MASS MEDIA STUDIES-835-CLASS XI Resource Material.pdf
Ch09 o com_pwb
1. 9
CHAPTER
Transfer of Thermal Energy
This chapter is organised into the sections as follows:
A. Conduction, Convection and Radiation
B. Challenging Questions
SECTION A Conduction, Convection and Radiation
1 A cup of hot tea is left in the same room as a bowl of ice-cream. What is likely to happen to both of
them after some time, if the two objects are both placed on the dining table?
A The tea becomes as cold as the ice-cream.
B The ice-cream becomes warmer than the tea.
C The tea cools to room temperature, the ice-cream melts and warms to room temperature.
D The tea becomes colder than before, but not as cold as the air in the room. [ C ]
2 When a piece of plastic is warmed on one end, the heated plastic molecules transfer thermal energy by
A streaming from the heated end to the colder end.
B vibrating more vigorously and knocking into their neighbours.
C radiating infra-red rays to the colder end.
D moving to the less dense region. [ B ]
3 Min Min steps on the carpeted floor and notices that it feels warmer than the marble floor. This is
because
A the carpet is darker in colour than the marble floor.
B there are layers of trapped air between the fibres of the carpet.
C she has a very low metabolic rate.
D the marble floor is white and shiny so it is a bad absorber. [ B ]
4 The diagram shows a metal pot containing some water which is placed on a hot plate.
The metal base is heated up quickly mainly by
A movement of electrons. B movement of solid molecules.
C molecular vibration. D emission of infra-red radiation. [ A ]
59
2. 5 (a) Describe, in terms of particles and electrons, how energy is transferred in the process of conduction
9 in
(i) wood; [2]
Transfer of Thermal Energy
When heated, the wood particles nearer to the heat source increase their energy of
vibrations, and pass this excess energy to the neighbouring molecules by increased
vibration.
(ii) copper wire. [2]
When heated, the free electrons nearer to the heat source speed up and increase their
collisions with the particles in the copper wire.
The increased particle vibration is passed along the wire.
This makes the copper particles further away vibrate more and the wire becomes hotter.
(b) Explain why:
(i) a cooking pot may have a copper base and a plastic handle; [1]
Copper material is a good conductor while plastic material is a poor conductor of heat.
(ii) wearing a few layers of T-shirt can keep you warm during cold nights. [1]
The layers of T-shirt help trap air, which is a poor conductor.
6 In an investigation to compare the thermal conductivity of four metals, Jocelyn coats the four different
metal rods with a thin layer of wax, and attaches each rod to a container of boiling water.
boiling water
rod coated with
a thin layer of wax
when cold
steel
iron
melted wax
aluminium
solid wax copper
(a) (i) What can you deduce from Jocelyn’s investigation? [1]
Copper conducts heat the fastest.
60
3. (ii) Explain your answer. [2]
The four metal rods are heated up equally, but the wax on the copper rod melts more 9
Transfer of Thermal Energy
within a shorter time compared to the remaining three metal rods. So more energy must
have been conducted by the copper rod to the wax at a faster rate.
(b) State what Jocelyn should do to ensure a fair test in her investigation. [2]
1. She should coat each metal with same thickness of wax.
2. The metal rods used should be of equal size and length.
7 An unlit match stick is placed on top of a lighted candle. The match bursts into flame because it is
heated up mainly by
A convection.
B convection and radiation.
C conduction and convection.
D conduction, convection and radiation. [ A ]
8 A beaker of water is heated up by convection. Why does the heated water rise?
A The water molecules expand and become less dense.
B The water contracts and its density increases.
C The water expands and its density decreases.
D The water expands and its density increases. [ C ]
9 The diagram below shows two vacuum flasks containing cold tea and hot tea respectively.
hot air rises
cold air sinks
cold tea hot tea
(a) In the case of the hot tea, draw the likely path of a convection current in the air in the container.
[1]
(b) Explain why it is essential to place a stopper over the hot tea to keep it warm, but not necessary to
do so for the cold tea to keep it cold. [2]
Hot air heated by the hot tea will rise and escape into the air, to be replaced by cold air which
sinks, cooling the hot tea by convection.
However, cold air above the cold tea has no tendency to rise due to its higher density than the
warmer air above. Hence cannot set up convection current. Cold tea is not significantly warmed.
61
4. 10 Julius switches on his table lamp and settles down to study for his Physics test. While he is at it, he
9 notices that the paper on the pin-board above the table lamp flips away from the board, and remains at
this position until he switches off the table lamp.
Transfer of Thermal Energy
(a) What is the cause of this strange behaviour of the paper on the pin-board? [2]
The table lamp heats up the air immediately above the lamp, causing the heated region above it
to expand. The heated air becomes less dense and rises. This upward movement of hot air flips
the paper away from the pin-board.
(b) (i) Comment on the difference in observation if Julius’s table lamp has a silver, shiny shade. [1]
It will take a slightly longer time for the paper to flip away from the pin board.
(ii) Explain your comment. [2]
Shiny, silver surface is a poor radiator Hence it takes a longer time to heat up the layer of
air above it by radiation.
11 (a) Describe, in terms of fluid movement, how a beaker of water is heated up by convection. [4]
– When heated, water molecules will gain energy and move more vigorously and further
apart.
– Water expands, causing a drop in its density.
– Heated water rises, to be replaced by colder water on the higher layer.
– The movement of water of due to density difference of the heated and cold water causes
convection current.
62
5. (b) Explain why:
(i) the heating element of the electric kettle is placed at the bottom; [2] 9
Transfer of Thermal Energy
The water heated by the heating element will expand and decrease in density. The cooler
air will cause the heated water to rise and be replaced by the colder water above, resulting
in convection current hence the water is heated up quickly.
If placed at the top, the top layer of hot water will not be able to move down by convection,
and since water is a poor conductor of heat, water cannot be efficiently heated up.
(ii) the freezer compartment in a refrigerator is placed on top. [2]
Cooler air from the freezer compartment is denser. The cooler air will tend to sink to the
lower shelf and hence cools the food below the freezer compartment more efficiently than
if the freezer compartment is to be placed at the bottom.
12 A block of heated metal cools down by emitting .
A ultraviolet rays B infra-red radiation
C heat waves D heat particles [ B ]
13 In a vacuum flask, which of the following energy transfers cannot be prevented?
A Conduction and convection B Convection and radiation
C Radiation D Convection [ C ]
63
6. 14 A vacuum flask has two shiny glass walls. The purpose of this feature is to reduce energy loss by
9
Transfer of Thermal Energy
A convection and conduction.
B conduction.
C radiation and convection.
D radiation. [ D ]
15 As Mrs Lee’s stove has broken down, she is considering on heating up a small amount of water by
filling a plastic bag with tap water and hanging it in a sunny place. What is the colour of the plastic bag
she should use in order to heat up the bag of water in the shortest possible time?
You may assume that Mrs Lee’s coloured plastic bags are made of the same material.
A clear, colourless
B black
C blue
D any colour will produce the same heating effect [ B ]
16 The diagram illustrates the structure of a solar panel used to heat water.
water pipes
in solar panel
roof
solar
panel
hot water out
cold water in
Which of the following materials would be the most suitable for the pipes in the solar panel?
A Black plastic
B White plastic
C Black painted copper
D Polished steel [ C ]
64
7. 17 Kim Seng sets up the apparatus as shown in the diagram below to investigate thermal energy transfer.
9
Transfer of Thermal Energy
dull polished
black surface
wooden cork
surface
a thin layer of wax
a thin layer of wax
(a) Kim Seng would like to gather reliable data on thermal energy transfer through this investigation.
[1]
State one action he can take to ensure that the experiment is fair.
Possible answers:
1 He can arrange the two surfaces to be of equal distance from the Bunsen flame.
2 He should use identical material for the two surfaces, although one is to be painted black.
3 The layer of wax use should be of equal thickness.
4 The wooden cork used should be identical.
5 The surface should have the same area.
(b) State and explain Kim Seng’s observation when he lights the Bunsen flame. [2]
The wooden cork attached to the dull, black surface will drop off first.
The wooden cork on the left gets heated up faster by radiation, as dull black surface is a better
absorber of thermal energy.
SECTION B Challenging Questions
1 The diagram shows a hot-water storage tank that Mr Tan has built.
metal tank
electric heater
hot water out
cold water in
65
8. (a) Using his Physics knowledge acquired while he was a young man, he gave the exterior of the
9 storage tank a shiny, silver coat of paint.
State and explain whether Mr Tan has applied his Physics knowledge correctly here. [2]
Transfer of Thermal Energy
Mr Tan has applied his understanding of radiation correctly. As silver, shiny surface is a bad
radiator, the thermal energy in the storage tank will take a longer time to be transferred
outwards. Hence water in the tank keeps warm longer. (The effect would have been better if he
had painted the interior part silver as well.)
(b) Mr Tan realises that to conserve the energy in the storage tank, he also needs to insulate the tank.
(i) Suggest one material he can use as insulator. [1]
Use fibre fill or styrofoam
(ii) Explain your choice. [1]
Such materials are bad conductors. They reduce energy loss by conduction through layers
of air trapped between the materials.
(c) However, Mr Tan makes a mistake in his design of the hot-water storage tank.
(i) Identify his mistake. Explain the consequence of this mistake. [2]
He places the heating element too high up in the storage tank.
The water in the tank is mainly heated up by conduction when heater is placed at this
position. Since water is a bad conductor, it will take a very long time to heat up the whole
tank.
(ii) How can his mistake be corrected? [1]
He should lower the heating element to the bottom of the tank.
(iii) Explain your answer to (c)(i). [3]
With the heating element positioned at the bottom of the tank, the water at the bottom is
heated up, expands and becomes less dense.
The less dense water will rise, and the denser, colder water will sink.
In this way, convection current can occur, heating the whole water tank quickly.
66