SlideShare una empresa de Scribd logo

Critical Thinking

•
•
O
ohassta

presentation given as an introductory session to teachers on a model of critical thinking.

EducaciónTecnología
1 de 21
Descargar para leer sin conexión
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking
Critical Thinking

Recomendados

Critical Thinking
Critical ThinkingCritical Thinking
Critical ThinkingDepartment of Education - Philippines
 
Cultivating Critical Thinking in Classroom
Cultivating Critical Thinking in ClassroomCultivating Critical Thinking in Classroom
Cultivating Critical Thinking in ClassroomSaima Abedi
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingCindy Clemens
 
Critical thinking powerpoint
Critical thinking powerpointCritical thinking powerpoint
Critical thinking powerpointBarbara Bali
 
Lecture 5: Creative Thinking
Lecture 5: Creative ThinkingLecture 5: Creative Thinking
Lecture 5: Creative ThinkingTathagat Varma
 
Introduction To Critical Thinking
Introduction To Critical ThinkingIntroduction To Critical Thinking
Introduction To Critical Thinkingmqamarhayat
 
Introduction to Critical Thinking Skills
Introduction to Critical Thinking SkillsIntroduction to Critical Thinking Skills
Introduction to Critical Thinking SkillsHanis Razak
 
Critical Thinking
Critical ThinkingCritical Thinking
Critical ThinkingMichelle Eckstein
 

Recomendados

Critical Thinking
Critical ThinkingCritical Thinking
Critical ThinkingDepartment of Education - Philippines
 
Cultivating Critical Thinking in Classroom
Cultivating Critical Thinking in ClassroomCultivating Critical Thinking in Classroom
Cultivating Critical Thinking in ClassroomSaima Abedi
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingCindy Clemens
 
Critical thinking powerpoint
Critical thinking powerpointCritical thinking powerpoint
Critical thinking powerpointBarbara Bali
 
Lecture 5: Creative Thinking
Lecture 5: Creative ThinkingLecture 5: Creative Thinking
Lecture 5: Creative ThinkingTathagat Varma
 
Introduction To Critical Thinking
Introduction To Critical ThinkingIntroduction To Critical Thinking
Introduction To Critical Thinkingmqamarhayat
 
Introduction to Critical Thinking Skills
Introduction to Critical Thinking SkillsIntroduction to Critical Thinking Skills
Introduction to Critical Thinking SkillsHanis Razak
 
Critical Thinking
Critical ThinkingCritical Thinking
Critical ThinkingMichelle Eckstein
 
What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?Peter Jeschofnig
 
Creative Thinking
Creative Thinking Creative Thinking
Creative Thinking Karim Wafa
 
McQueary critical thinking workshop
McQueary critical thinking workshopMcQueary critical thinking workshop
McQueary critical thinking workshopCurtis McQueary
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingGregor Horvat
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingClara Novy
 
6. critical thinking skills 2
6. critical thinking skills 26. critical thinking skills 2
6. critical thinking skills 2Majid Safadaran
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingACIF ALI
 
Critical Thinking
Critical Thinking Critical Thinking
Critical Thinking Corey Edwards
 
Critical thinking skills ppt
Critical thinking skills pptCritical thinking skills ppt
Critical thinking skills pptTauqeer Abbas
 
Critical Thinking: Building Good Judgement
Critical Thinking: Building Good JudgementCritical Thinking: Building Good Judgement
Critical Thinking: Building Good JudgementPrasenjit Mitra
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingLance Jones
 
Critical Thinking in Education
Critical Thinking in EducationCritical Thinking in Education
Critical Thinking in EducationElianaCrespo
 
What is critical thinking
What is critical thinkingWhat is critical thinking
What is critical thinkingPrasad A.S
 
Conclusions in Critical Thinking
Conclusions in Critical ThinkingConclusions in Critical Thinking
Conclusions in Critical Thinkinglbrook
 
Critical Thinking
Critical ThinkingCritical Thinking
Critical ThinkingDavid Carless
 
Developing Critical Thinking Skills
Developing Critical Thinking SkillsDeveloping Critical Thinking Skills
Developing Critical Thinking SkillsMohamed Nasir
 
Critical And Creative Thinking Henderson
Critical And Creative Thinking HendersonCritical And Creative Thinking Henderson
Critical And Creative Thinking HendersonMariellesimone
 
Introduction to critical thinking
Introduction to critical thinkingIntroduction to critical thinking
Introduction to critical thinkingAurora Computer Studies
 
Critical thinking activities for children
Critical thinking activities for childrenCritical thinking activities for children
Critical thinking activities for childrenDr. Sapna Sharma
 
Critical thinking vs. creative thinking
Critical thinking vs. creative thinkingCritical thinking vs. creative thinking
Critical thinking vs. creative thinkingJANNETH OBISPO
 
Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1ronsears
 
Advanced Design Thinking Tools
Advanced Design Thinking ToolsAdvanced Design Thinking Tools
Advanced Design Thinking ToolsOlga Dotter
 

Más contenido relacionado

La actualidad más candente

What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?Peter Jeschofnig
 
Creative Thinking
Creative Thinking Creative Thinking
Creative Thinking Karim Wafa
 
McQueary critical thinking workshop
McQueary critical thinking workshopMcQueary critical thinking workshop
McQueary critical thinking workshopCurtis McQueary
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingClara Novy
 
6. critical thinking skills 2
6. critical thinking skills 26. critical thinking skills 2
6. critical thinking skills 2Majid Safadaran
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingACIF ALI
 
Critical thinking skills ppt
Critical thinking skills pptCritical thinking skills ppt
Critical thinking skills pptTauqeer Abbas
 
Critical Thinking: Building Good Judgement
Critical Thinking: Building Good JudgementCritical Thinking: Building Good Judgement
Critical Thinking: Building Good JudgementPrasenjit Mitra
 
Critical thinking
Critical thinkingCritical thinking
Critical thinkingLance Jones
 
Critical Thinking in Education
Critical Thinking in EducationCritical Thinking in Education
Critical Thinking in EducationElianaCrespo
 
What is critical thinking
What is critical thinkingWhat is critical thinking
What is critical thinkingPrasad A.S
 
Conclusions in Critical Thinking
Conclusions in Critical ThinkingConclusions in Critical Thinking
Conclusions in Critical Thinkinglbrook
 
Developing Critical Thinking Skills
Developing Critical Thinking SkillsDeveloping Critical Thinking Skills
Developing Critical Thinking SkillsMohamed Nasir
 
Critical And Creative Thinking Henderson
Critical And Creative Thinking HendersonCritical And Creative Thinking Henderson
Critical And Creative Thinking HendersonMariellesimone
 
Critical thinking activities for children
Critical thinking activities for childrenCritical thinking activities for children
Critical thinking activities for childrenDr. Sapna Sharma
 
Critical thinking vs. creative thinking
Critical thinking vs. creative thinkingCritical thinking vs. creative thinking
Critical thinking vs. creative thinkingJANNETH OBISPO
 

La actualidad más candente (20)

What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?What is Critical Thinking, and How to Teach It?
What is Critical Thinking, and How to Teach It?
 
Creative Thinking
Creative Thinking Creative Thinking
Creative Thinking
 
McQueary critical thinking workshop
McQueary critical thinking workshopMcQueary critical thinking workshop
McQueary critical thinking workshop
 
Critical thinking
Critical thinkingCritical thinking
Critical thinking
 
Critical thinking
Critical thinkingCritical thinking
Critical thinking
 
6. critical thinking skills 2
6. critical thinking skills 26. critical thinking skills 2
6. critical thinking skills 2
 
Critical thinking
Critical thinkingCritical thinking
Critical thinking
 
Critical Thinking
Critical Thinking Critical Thinking
Critical Thinking
 
Critical thinking skills ppt
Critical thinking skills pptCritical thinking skills ppt
Critical thinking skills ppt
 
Critical Thinking: Building Good Judgement
Critical Thinking: Building Good JudgementCritical Thinking: Building Good Judgement
Critical Thinking: Building Good Judgement
 
Critical thinking
Critical thinkingCritical thinking
Critical thinking
 
Critical Thinking in Education
Critical Thinking in EducationCritical Thinking in Education
Critical Thinking in Education
 
What is critical thinking
What is critical thinkingWhat is critical thinking
What is critical thinking
 
Conclusions in Critical Thinking
Conclusions in Critical ThinkingConclusions in Critical Thinking
Conclusions in Critical Thinking
 
Critical Thinking
Critical ThinkingCritical Thinking
Critical Thinking
 
Developing Critical Thinking Skills
Developing Critical Thinking SkillsDeveloping Critical Thinking Skills
Developing Critical Thinking Skills
 
Critical And Creative Thinking Henderson
Critical And Creative Thinking HendersonCritical And Creative Thinking Henderson
Critical And Creative Thinking Henderson
 
Introduction to critical thinking
Introduction to critical thinkingIntroduction to critical thinking
Introduction to critical thinking
 
Critical thinking activities for children
Critical thinking activities for childrenCritical thinking activities for children
Critical thinking activities for children
 
Critical thinking vs. creative thinking
Critical thinking vs. creative thinkingCritical thinking vs. creative thinking
Critical thinking vs. creative thinking
 

Destacado

Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1ronsears
 
Advanced Design Thinking Tools
Advanced Design Thinking ToolsAdvanced Design Thinking Tools
Advanced Design Thinking ToolsOlga Dotter
 
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.com
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.comCritical Thinking Tools by Eric Frangenheim on Globaledtalk.com
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.comCraig Hansen
 
15 clever thinking tools to create winning ideas quickly
15 clever thinking tools to create winning ideas quickly15 clever thinking tools to create winning ideas quickly
15 clever thinking tools to create winning ideas quicklyChris Thomason
 
Five Thinking Errors Sabotaging Your Brain
Five Thinking Errors Sabotaging Your BrainFive Thinking Errors Sabotaging Your Brain
Five Thinking Errors Sabotaging Your BrainAdam Sicinski
 
NTS ANALYTICAL REASONING QUESTION
NTS ANALYTICAL REASONING QUESTIONNTS ANALYTICAL REASONING QUESTION
NTS ANALYTICAL REASONING QUESTIONSIKSAVI
 
6 Steps to Critical Thinking
6 Steps to Critical Thinking6 Steps to Critical Thinking
6 Steps to Critical Thinkingolyaodchimp
 
Higher order thinking_skills
Higher order thinking_skillsHigher order thinking_skills
Higher order thinking_skillsdiegocampillo
 
Higher order thinking skills presentation
Higher order thinking skills presentationHigher order thinking skills presentation
Higher order thinking skills presentationKenny Pieper
 
Teaching Higher Order Thinking & 21st Century Skills
Teaching Higher Order Thinking & 21st Century SkillsTeaching Higher Order Thinking & 21st Century Skills
Teaching Higher Order Thinking & 21st Century SkillsTimothy Wooi
 
Developing Higher-Order Thinking Skills
Developing Higher-Order Thinking SkillsDeveloping Higher-Order Thinking Skills
Developing Higher-Order Thinking SkillsAldwin Cayetano
 
Critical Thinking - With Case Study
Critical Thinking - With Case StudyCritical Thinking - With Case Study
Critical Thinking - With Case StudyKaryn Thng
 

Destacado (20)

Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1Critical Thinking Ppt Week 1
Critical Thinking Ppt Week 1
 
Advanced Design Thinking Tools
Advanced Design Thinking ToolsAdvanced Design Thinking Tools
Advanced Design Thinking Tools
 
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.com
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.comCritical Thinking Tools by Eric Frangenheim on Globaledtalk.com
Critical Thinking Tools by Eric Frangenheim on Globaledtalk.com
 
15 clever thinking tools to create winning ideas quickly
15 clever thinking tools to create winning ideas quickly15 clever thinking tools to create winning ideas quickly
15 clever thinking tools to create winning ideas quickly
 
Five Thinking Errors Sabotaging Your Brain
Five Thinking Errors Sabotaging Your BrainFive Thinking Errors Sabotaging Your Brain
Five Thinking Errors Sabotaging Your Brain
 
Thinking Errors: Understanding and Addressing Them to Improve Recovery
Thinking Errors: Understanding and Addressing Them to Improve RecoveryThinking Errors: Understanding and Addressing Them to Improve Recovery
Thinking Errors: Understanding and Addressing Them to Improve Recovery
 
CoRT 1 Breadth Thinking Tools Workbook
CoRT 1 Breadth Thinking Tools WorkbookCoRT 1 Breadth Thinking Tools Workbook
CoRT 1 Breadth Thinking Tools Workbook
 
Public relation.ppt
Public relation.pptPublic relation.ppt
Public relation.ppt
 
NTS ANALYTICAL REASONING QUESTION
NTS ANALYTICAL REASONING QUESTIONNTS ANALYTICAL REASONING QUESTION
NTS ANALYTICAL REASONING QUESTION
 
Higher order thinking
Higher order thinkingHigher order thinking
Higher order thinking
 
6 Steps to Critical Thinking
6 Steps to Critical Thinking6 Steps to Critical Thinking
6 Steps to Critical Thinking
 
Hots
HotsHots
Hots
 
Higher order thinking_skills
Higher order thinking_skillsHigher order thinking_skills
Higher order thinking_skills
 
Higher order thinking skills presentation
Higher order thinking skills presentationHigher order thinking skills presentation
Higher order thinking skills presentation
 
Teaching Higher Order Thinking & 21st Century Skills
Teaching Higher Order Thinking & 21st Century SkillsTeaching Higher Order Thinking & 21st Century Skills
Teaching Higher Order Thinking & 21st Century Skills
 
Developing Higher-Order Thinking Skills
Developing Higher-Order Thinking SkillsDeveloping Higher-Order Thinking Skills
Developing Higher-Order Thinking Skills
 
Critical Thinking - With Case Study
Critical Thinking - With Case StudyCritical Thinking - With Case Study
Critical Thinking - With Case Study
 
Problem-solving method
Problem-solving methodProblem-solving method
Problem-solving method
 
Thinking skills
Thinking skillsThinking skills
Thinking skills
 
Thinking
ThinkingThinking
Thinking
 

Último

Separation of Lanthanides/ Lanthanides and Actinides
Separation of Lanthanides/ Lanthanides and ActinidesSeparation of Lanthanides/ Lanthanides and Actinides
Separation of Lanthanides/ Lanthanides and ActinidesFatimaKhan178732
 
Beyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactBeyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactPECB
 
mini mental status format.docx
mini mental status format.docxmini mental status format.docx
mini mental status format.docxPoojaSen20
 
1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdf1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdfQucHHunhnh
 
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptxOrganic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptxVS Mahajan Coaching Centre
 
Measures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeMeasures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeThiyagu K
 
APM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAPM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAssociation for Project Management
 
The byproduct of sericulture in different industries.pptx
The byproduct of sericulture in different industries.pptxThe byproduct of sericulture in different industries.pptx
The byproduct of sericulture in different industries.pptxShobhayan Kirtania
 
Disha NEET Physics Guide for classes 11 and 12.pdf
Disha NEET Physics Guide for classes 11 and 12.pdfDisha NEET Physics Guide for classes 11 and 12.pdf
Disha NEET Physics Guide for classes 11 and 12.pdfchloefrazer622
 
Sanyam Choudhary Chemistry practical.pdf
Sanyam Choudhary Chemistry practical.pdfSanyam Choudhary Chemistry practical.pdf
Sanyam Choudhary Chemistry practical.pdfsanyamsingh5019
 
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...Krashi Coaching
 
social pharmacy d-pharm 1st year by Pragati K. Mahajan
social pharmacy d-pharm 1st year by Pragati K. Mahajansocial pharmacy d-pharm 1st year by Pragati K. Mahajan
social pharmacy d-pharm 1st year by Pragati K. Mahajanpragatimahajan3
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDThiyagu K
 
A Critique of the Proposed National Education Policy Reform
A Critique of the Proposed National Education Policy ReformA Critique of the Proposed National Education Policy Reform
A Critique of the Proposed National Education Policy ReformChameera Dedduwage
 
Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Celine George
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsTechSoup
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introductionMaksud Ahmed
 

Último (20)

Separation of Lanthanides/ Lanthanides and Actinides
Separation of Lanthanides/ Lanthanides and ActinidesSeparation of Lanthanides/ Lanthanides and Actinides
Separation of Lanthanides/ Lanthanides and Actinides
 
Beyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactBeyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global Impact
 
mini mental status format.docx
mini mental status format.docxmini mental status format.docx
mini mental status format.docx
 
1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdf1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdf
 
Código Creativo y Arte de Software | Unidad 1
Código Creativo y Arte de Software | Unidad 1Código Creativo y Arte de Software | Unidad 1
Código Creativo y Arte de Software | Unidad 1
 
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptxOrganic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
 
Measures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and ModeMeasures of Central Tendency: Mean, Median and Mode
Measures of Central Tendency: Mean, Median and Mode
 
APM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across SectorsAPM Welcome, APM North West Network Conference, Synergies Across Sectors
APM Welcome, APM North West Network Conference, Synergies Across Sectors
 
The byproduct of sericulture in different industries.pptx
The byproduct of sericulture in different industries.pptxThe byproduct of sericulture in different industries.pptx
The byproduct of sericulture in different industries.pptx
 
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptxINDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
 
Disha NEET Physics Guide for classes 11 and 12.pdf
Disha NEET Physics Guide for classes 11 and 12.pdfDisha NEET Physics Guide for classes 11 and 12.pdf
Disha NEET Physics Guide for classes 11 and 12.pdf
 
Sanyam Choudhary Chemistry practical.pdf
Sanyam Choudhary Chemistry practical.pdfSanyam Choudhary Chemistry practical.pdf
Sanyam Choudhary Chemistry practical.pdf
 
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...
Kisan Call Centre - To harness potential of ICT in Agriculture by answer farm...
 
social pharmacy d-pharm 1st year by Pragati K. Mahajan
social pharmacy d-pharm 1st year by Pragati K. Mahajansocial pharmacy d-pharm 1st year by Pragati K. Mahajan
social pharmacy d-pharm 1st year by Pragati K. Mahajan
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SD
 
Advance Mobile Application Development class 07
Advance Mobile Application Development class 07Advance Mobile Application Development class 07
Advance Mobile Application Development class 07
 
A Critique of the Proposed National Education Policy Reform
A Critique of the Proposed National Education Policy ReformA Critique of the Proposed National Education Policy Reform
A Critique of the Proposed National Education Policy Reform
 
Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17Advanced Views - Calendar View in Odoo 17
Advanced Views - Calendar View in Odoo 17
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The Basics
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introduction