I used a nitrogen membrane and Stirling cryocooler to liquefy nitrogen out of the air. For this video I partnered with Starbucks to celebrate their Nitro Cold Brew. Order one here: https://starbucks.app.link/derekmuller

Making liquid nitrogen is hard - in fact up until 150 years ago scientists doubted whether it was even possible to liquefy nitrogen. In 1823, At the royal institution in London, Michael Faraday first produced liquid chlorine, kind of accidentally by putting it under high pressure. He similarly liquefied ammonia.

Borrowing a mixture from Thilorier in France, a combination of dry ice, snow and ether, he reached a temperature of -110C. By 1845 he used this mixture plus a hand pump to pressurize gases to liquefy all the known gases except six, which included oxygen and nitrogen. These became known as the “permanent” gases.

A French Physicist Aimé compressed oxygen and nitrogen in tanks and then lowered them into the ocean over 1.6km deep, where the pressure got up to 200 atmospheres. Still the gases didn’t liquefy.

Only at the end of 1877 were the first droplets of liquid oxygen and liquid nitrogen produced, by Cailletet in France. He first tried oxygen by compressing it up to 300 atmospheres, cooled to -30C, but that wasn't even enough to liquefy oxygen. But when he suddenly released the pressure, the expanding gas cooled, he estimated to -200C and he saw a mist and then droplets slide down the walls of his vessel.

It's amazing how far we've come in that now I can purchase a helium-based cryocooler. It compresses and expands the gas to absorb heat from the tip of the cold finger and eject it into the surroundings at ambient temperature.

Join me on the lesson where you will learn how to convert improper fractions to mixed numbers (and how to convert mixed numbers to improper fractions). Lesson Guide: https://bit.ly/2UE9HXe

Key Questions: What is a mixed number? What is a proper fraction? What is an improper fraction? What is the difference between a proper fraction and an improper fraction? How do you convert an improper fraction to a mixed number?

This Converting Improper Fractions to Mixed Numbers video lesson includes a free lesson guide and Converting Improper Fractions to Mixed Numbers worksheet with an answer key. Click the links below to get yours:

★Get Your Free Converting Improper Fractions to Mixed Numbers Lesson Guide: https://bit.ly/2UE9HXe

★Get Your Free Converting Improper Fractions to Mixed Numbers Worksheet: https://bit.ly/2UE9HXe

★ Want more FREE weekly math videos? Subscribe Now: http://bit.ly/1OVJnyh

★★ Why Math? Download YOUR Free eBook and sign-up for our FREE weekly newsletter: http://www.mashupmath.com/resources/

Topic - Computer Input and Output Devices

Hello Kids,
In this video, we are going to learn about computer Input and output Device and their uses.
_________________________________________________________________________________________

AAtoons Kids
play N learn
Website - http://www.aatoonskids.com

Facebook Page - https://www.facebook.com/aatoonskids1

Twitter - https://twitter.com/aatoonskids
__________________________________________________________


Links of Our other Educational Videos

Hindi Varnamala for Kids - https://www.youtube.com/watch?v=sQ6PqXJ9ky8

Multiplication Table 1 to 10 - https://www.youtube.com/watch?v=euxW2yV0K6g

Hindi Varnamala SWAR VARN - https://www.youtube.com/watch?v=8UWtPMwNTzs&t=3s

Animals Name - https://www.youtube.com/watch?v=dtN5duo27jE

Months of Year - https://www.youtube.com/watch?v=KjoHCagm7tg

Insects Name - https://www.youtube.com/watch?v=L2uZiN54Sf0

Opposite Words - https://youtu.be/T_QOA_1AXhU
___________________________________________________________________________________________

#Computer
#OutputDevice
#InputDevice
#AAtoonsKids

PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateOKAY
↓ More info and sources below ↓

Head over to Animal IQ on Terra: https://youtu.be/Nc3mUNkJZZk
Celebrate Earth Day with other PBS Channels! https://bit.ly/32nmIsp

We’re on PATREON! Join the community ►► https://www.patreon.com/itsokaytobesmart
SUBSCRIBE so you don’t miss a video! ►► http://bit.ly/iotbs_sub

Ocean currents are our planet’s circulatory system, and they keep everything from ecosystems to the climate healthy. But we’re changing Earth in ways that threaten to disrupt and even break critical ocean currents like the planet-wide Great Ocean Conveyor. This could have devastating effects on our future. In this video, we explain how ocean currents work, how climate change is threatening to disrupt them, and what we can do to stop that from happening.

References: https://sites.google.com/view/....ocean-conveyor-belt/

-----------

Big Thank you to our Brain Trust Patrons:

Andrew Campbell
Robert
Brian Chang
Roy Lasris
Javier Soto
dani bowman
David Johnston
Zenimal
Salih Arslan
Baerbel Winkler
Robert Young
Amy Sowada
Benjamin Teinby
Eric Meer
Peter Ehrnstrom
Dustin
Marcus Tuepker
Karen Haskell
AlecZero


Join us on Patreon!
https://patreon.com/itsokaytobesmart

Twitter
http://www.twitter.com/DrJoeHanson
http://www.twitter.com/okaytobesmart

Instagram
http://www.instagram.com/DrJoeHanson
http://www.instagram.com/okaytobesmart

Merch
https://store.dftba.com/collec....tions/its-okay-to-be

Facebook
https://www.facebook.com/itsokaytobesmartpbs/

On this lesson, you will learn how to use the arc length formula and the sector area formula to solve geometry math problems. Lesson Guide: https://bit.ly/2Rj7Whq

This lesson answers the questions: What is arc length formula? What is sector area formula? How do I find arc length? How do I find sector area? What is a central angle? How do I find an arc?

This video lesson includes a free lesson guide and equation of a circle worksheet with an answer key. Click the links below to get yours:

★Get Your Arc Length and Sector Area Lesson Guide: https://bit.ly/2Rj7Whq

★Get Your Free Arc Length and Sector Area Worksheet: https://bit.ly/2Rj7Whq

★ Want more FREE weekly math videos? Subscribe Now: http://bit.ly/1OVJnyh

★★ Why Math? Download YOUR Free eBook and sign-up for our FREE weekly newsletter: http://www.mashupmath.com/resources/

This time, the cross section of our solid is given as the area between two curves.

Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/ap-calculus-ab/ab-applications-definite-integrals/ab-vol-cross-sections/e/volumes-of-solids-of-known-cross-section?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusAB

Watch the next lesson: https://www.khanacademy.org/math/ap-calculus-ab/ab-applications-definite-integrals/ab-disk-method/v/disk-method-around-x-axis?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusAB

Missed the previous lesson? https://www.khanacademy.org/math/ap-calculus-ab/ab-applications-definite-integrals/ab-vol-cross-sections/v/volume-solid-semicircle-cross-section?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusAB

AP Calculus AB on Khan Academy: Bill Scott uses Khan Academy to teach AP Calculus at Phillips Academy in Andover, Massachusetts, and heÕs part of the teaching team that helped develop Khan AcademyÕs AP lessons. Phillips Academy was one of the first schools to teach AP nearly 60 years ago.

About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world. Our resources cover preschool through early college education, including math, biology, chemistry, physics, economics, finance, history, grammar and more. We offer free personalized SAT test prep in partnership with the test developer, the College Board. Khan Academy has been translated into dozens of languages, and 100 million people use our platform worldwide every year. For more information, visit www.khanacademy.org, join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan AcademyÕs AP Calculus AB channel: https://www.youtube.com/channe....l/UCyoj0ZF4uw8VTFbml
Subscribe to Khan Academy: https://www.youtube.com/subscr....iption_center?add_us

👟 Vessis early Black Friday sale is on now! Vessi is giving away a pair of socks of your choice to the first 100 shoes sold using my code SOCKSSIMPLEHISTORY. Get your style and size you want now before they sell out! Check out their Early Black Friday sale at https://vessi.com/SIMPLEHISTORY
.. Free shipping to CA, US, AU,JP, TW, KR, SGP.

You may have heard of people dancing to death, laughing to death or sitting on a throne to death, but there are many more surprising stories told to the Grim Reaper when the scythe is resting by the door.
What follows are what happens when you really want to stick it to your enemies for slowing your conquest of the Mediterranean, the consequences of leaving a nuclear reactor to inexperienced workers, the measures people will go to when they’re furious and hungry, and an unfortunate incident relating with an elephant-sized general.

2nd Channel: https://www.youtube.com/channe....l/UCPdc6bs3I8s6Y4QE_
Become a Simple History member: https://www.youtube.com/simplehistory/join
Support us on Patreon: https://www.patreon.com/simplehistory

Copyright: DO NOT translate and re-upload our content on Youtube or other social media.

SIMPLE HISTORY MERCHANDISE

Get the Simple History books on Amazon:

https://www.amazon.com/Daniel-....Turner-%60/e/B00H5TY

T-Shirts

https://teespring.com/stores/s....imple-history-offici

Simple history gives you the facts, simple!

See the book collection here:

Amazon USA

http://www.amazon.com/Daniel-Turner/e/B00H5TYLAE/


Amazon UK
http://www.amazon.co.uk/Daniel....-Turner/e/B00H5TYLAE


https://www.facebook.com/Simpl....e-History-5494376751

https://twitter.com/SimpleHistoryYT


Credit:
Created by Daniel Turner (B.A. (Hons) in History, University College London)
Script:
Natasha Martell



American Battlefield Trust. n.d. “John Sedgwick.”

BBC News. “Segway boss died in 'act of courtesy,” July 15, 2011. BBC.

Bradley, James. “Flyboys: A True Story of Courage.” Boston: Little Brown, (2003).

Crowley, Roger. “Bragadin’s Defense,” April 19, 2018. HistoryNet.

Crowley, Roger. “Empires of the Sea.” New York: Random House, 2008.

History.com Editors. “Dancer Isadora Duncan is killed in car accident.” Last modified September 11, 2019. History.

Idaho National Laboratory. n.d. “SL-1, Idaho: Just The Facts.”

Naki, Emrah. “Conquest of Cyprus by the Turks: Divergence of the Early Modern Period and Establishment of Status Quo in the Mediterranean.” Gazi Akademik Bakış (November 19, 2019): 1-16.

Spokane Daily Chronicle. “3 Die in Reactor Blast,” 75th Year, No. 91, January 4, 1961.

The Spokesman Review. “3 Technicians Die in Reactor Blast,” 78th Year, No. 236, January 5, 1961.

T. McMahon, Martin. “THE DEATH OF GENERAL JOHN SEDGWICK.” In Battles and Leaders of the Civil War: Being for the Most Part Contributions by Union and Confederate Officers. New York: The Century Co., 1884.

United States Atomic Energy Commission. “IDO-19311 Final Report of SL-1 Recovery Operation.” Idaho Falls: General Electric Corporation, 1962.

Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/PBSDSDonate

Try Lynda.com: http://lynda.com/okay
Best experienced in 240p or lower
↓ More info and sources below ↓

Check out Stanford’s “Raw Data” podcast:
https://soundcloud.com/rawdatapodcast
https://itunes.apple.com/us/podcast/r...

Most numbers in the video are from this book:
Big Data: A Revolution That Will Transform How We Live, Work, and Think - Viktor Mayer-Schönberger and Kenneth Cukier
http://amzn.to/1Vhc3Ei

Sources:
DNA Storage: http://cen.acs.org/articles/93/i35/Sc...

Square kilometer array (and other data scales): http://highscalability.com/blog/2012/...

How much data does ___ store? http://techexpectations.org/2015/03/2...


Have an idea for an episode or an amazing science question you want answered? Leave a comment or check us out at the links below!
Follow on Twitter: http://twitter.com/okaytobesmart
http://twitter.com/jtotheizzoe
Follow on Tumblr: http://www.itsokaytobesmart.com
Follow on Instagram: http://instagram.com/jtotheizzoe
Follow on Snapchat: YoDrJoe

-----------------
It’s Okay To Be Smart is written and hosted by Joe Hanson, Ph.D.
Follow me on Twitter: @jtotheizzoe
Email me: itsokaytobesmart AT gmail DOT com
Facebook: http://www.facebook.com/itsokaytobesmart
For more awesome science, check out: http://www.itsokaytobesmart.com
Produced by PBS Digital Studios: http://www.youtube.com/user/pbsdigita...

Music via APM
Stock images from Shutterstock, stock footage from Videoblocks (unless otherwise noted)

Over the years, countless ideas, initiatives, and mandates for improving student achievement and public schooling have been tried out, but very often have fallen short. Why? In a preview of his keynote discussion, sought-after K-12 school improvement expert Mike Schmoker argues that district and school leaders, along with teachers, need to be empowered to prioritize what is most effective for helping students succeed. See him speak at our live event in Washington, D.C. on March 31, 2017. http://leaders.edweek.org/event-details ____________________

Want more stories about schools across the nation, including the latest news and unique perspectives on education issues? Visit www.edweek.org.

About Education Week:
Education Week is America’s most trusted source of independent K-12 education news, analysis, and opinion. Our work serves to raise the level of understanding and discourse about education among school and district leaders, policymakers, researchers, teachers, and the public. Published by the nonprofit organization Editorial Projects in Education, Education Week has been providing award-winning coverage of the field for over 35 years.

Follow Education Week:
- Subscribe to our Channel: http://www.youtube.com/subscri....ption_center?add_use
- On Facebook at https://www.facebook.com/edweek/
- On Twitter at https://twitter.com/educationweek/
- On LinkedIn at https://www.linkedin.com/company/education-week

To license video footage from Editorial Projects in Education please contact the Education Week Library at library@epe.org.

How is this city like a cell?
They both need to store water and other materials.
Welcome to MooMooMath and Science and organelles and in this video, I will cover the main functions of a vacuole.
Vacuoles store water and waste and other materials in eukaryotic cells. Remember these are cells with membrane-bound organelles and a nucleus.

Vacuoles are storage sacks in plants and animal cells protists but they are not found in
bacterial cells in addition to storing water, vacuoles also store enzymes, waste, and even old damaged organelles.

You may also enjoy
Mitochondria
https://www.youtube.com/watch?v=SWsjm2a-usk

Pass the GED Math Test by going through these handpicked standard GED Test questions. Please, watch the entire video for best results

Get Our GED Math Course - https://ultimateged.com.
Get step by step videos, covering everything you need to Pass.
Practice Test, VIP community and More.

Join this channel to get access to perks: Exclusive Videos and More.
https://www.youtube.com/channe....l/UCS1YNEY54RYgt9Obz

Get Our Premium Algebra Course -- ultimate-algebra.com
Over 200+ videos with quizzes, covers pre-algebra, algebra 1 and algebra 2.

Important GED Math Videos
1.GED Math from Absolute Beginning
https://youtu.be/JVcLECqJ1o4
2. No Calculator GED Math Section
https://youtu.be/VnjbJLi7VL4
3. GED Math Geometry Section
https://youtu.be/KN5dBacDs1Q
4. Complete GED Science Course
https://youtu.be/2n3GRShhaIA
5. GED Math 2024
https://youtu.be/Qa0JdCClC10
Important Algebra Videos
1.Algebra 1 for Beginners
https://www.youtube.com/watch?v=tTomwopxKFE
2. Easiest Algebra Lesson
https://www.youtube.com/watch?v=V3dFHt9p5W8
3. Solving Quadratic Equations
https://youtu.be/S9EN26HJqBw
4. Absolute Value
https://youtu.be/o_tk6iYz-WY
5. Understanding how to Solving Equations
https://youtu.be/sHTFUo3xRWQ
6. Dealing with Exponents
https://youtu.be/oL-pBONMW3o

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/ec....onomics-finance-doma

Understanding how hedge funds are structured and how the managers get paid. Created by Sal Khan.

Watch the next lesson:
https://www.khanacademy.org/economics-finance-domain/core-finance/investment-vehicles-tutorial/hedge-funds/v/are-hedge-funds-bad?utm_source=YT&utm_medium=Desc&utm_campaign=financeandcapitalmarkets

Missed the previous lesson? Watch here: https://www.khanacademy.org/economics-finance-domain/core-finance/investment-vehicles-tutorial/hedge-funds/v/hedge-funds-intro?utm_source=YT&utm_medium=Desc&utm_campaign=financeandcapitalmarkets

Finance and capital markets on Khan Academy: Hedge funds have absolutely nothing to do with shrubbery. Their name comes from the fact that early hedge funds (and some current ones) tried to "hedge" their exposure to the market (so they could, in theory, do well in an "up" or "down" market as long as they were good at picking the good companies). Today, hedge funds represent a huge class investment funds. They are far less regulated than, say, mutual funds. In exchange for this, they aren't allowed to market or take investments from "unsophisticated" investors. Some use their flexibility to mitigate risk, other use it to amplify it.

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan Academy’s Finance and Capital Markets channel: https://www.youtube.com/channe....l/UCQ1Rt02HirUvBK2D2
Subscribe to Khan Academy: https://www.youtube.com/subscr....iption_center?add_us

This video shows how you can create an unrolling circle in Geogebra, in other to explain the circumference of a circle.

This chemistry video tutorial provides a basic introduction into molecular orbital theory. It describes the formation of bonding and antibonding molecular orbitals from the combination of atomic orbitals. It explains how to calculate the bond order of homonuclear diatomic molecule as well as heteronuclear diatomic molecules. It also contains examples and practice problems of homonuclear and heteronuclear molecular ions.

Access The Full 1 Hour Video:
https://www.patreon.com/MathScienceTutor

Direct Link to The Full Video:
https://bit.ly/3VY2Mpv

Chemistry PDF Worksheets:
https://www.video-tutor.net/ch....emistry-basic-introd

_________________________________
Access The Full Video on YouTube:
https://www.youtube.com/watch?v=MdobdIhf_dU

Join The YouTube Membership Program:
https://bit.ly/46xaQTR

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/ec....onomics-finance-doma

Chapter 11: Restructuring through a bankruptcy. Created by Sal Khan.

Watch the next lesson:
https://www.khanacademy.org/economics-finance-domain/core-finance/stock-and-bonds/dilution-tutorial/v/stock-dilution?utm_source=YT&utm_medium=Desc&utm_campaign=financeandcapitalmarkets

Missed the previous lesson? Watch here: https://www.khanacademy.org/economics-finance-domain/core-finance/stock-and-bonds/venture-capital-and-capital-markets/v/chapter-7-bankruptcy-liquidation?utm_source=YT&utm_medium=Desc&utm_campaign=financeandcapitalmarkets

Finance and capital markets on Khan Academy: This is an old set of videos, but if you put up with Sal's messy handwriting (it has since improved) and spotty sound, there is a lot to be learned here. In particular, this tutorial walks through starting, financing and taking public a company (and even talks about what happens if it has trouble paying its debts).

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan Academy’s Finance and Capital Markets channel: https://www.youtube.com/channe....l/UCQ1Rt02HirUvBK2D2
Subscribe to Khan Academy: https://www.youtube.com/subscr....iption_center?add_us

Become a Simple History member: https://www.youtube.com/simplehistory/join
Support us on Patreon: https://www.patreon.com/simplehistory

Copyright: DO NOT translate and re-upload our content on Youtube or other social media.

SIMPLE HISTORY MERCHANDISE

Get the Simple History books on Amazon:

https://www.amazon.com/Daniel-....Turner-%60/e/B00H5TY

T-Shirts

https://teespring.com/stores/s....imple-history-offici

Simple history gives you the facts, simple!

See the book collection here:

Amazon USA

http://www.amazon.com/Daniel-Turner/e/B00H5TYLAE/


Amazon UK
http://www.amazon.co.uk/Daniel....-Turner/e/B00H5TYLAE


https://www.facebook.com/Simpl....e-History-5494376751

https://twitter.com/SimpleHistoryYT


Credit:
Created by Daniel Turner

Script by Conan White & Daniel Turner

Narrator:

Chris Kane
https://vocalforge.com/

Music Credit:
Long Note Four by Kevin MacLeod is licensed under a Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/)
Source: http://incompetech.com/music/r....oyalty-free/index.ht
Artist: http://incompetech.com/

Sources: https://pastebin.com/Gb4adQxV

Download Warpath using our link, and play the new sniper update: https://bit.ly/3vp4vJV
Register to the tournament and win up to up to $15,000 in prizes: https://brothersunite-warpath.....lilith.com/?media=ko

Pavlov’s House
The stronghold of the 13th Guards was located at the bombed out NKVD headquarters, a soviet government law enforcement agency. From this location, the troops resisted the initial German assault and took to improving their defensive position. On September 25th, the commander of the 42nd Guards Rifle Regiment ordered the men of his 3rd Rifle Battalion to capture two buildings that seemed like a good position for setting up a defense against German attacks. Junior Sergeant Yakov Fedotovich Pavlov of the 13th Guards Rifle Division was tasked with seizing one of the buildings at the edge of the 9th January Square. On September 27th, followed by three soldiers from his squad, Pavlov entered the building under the cover of night and drove the defending Germans out of it. Once in their hands, the commander of the 42nd regiment designated it “Pavlov’s House”.



Become a Simple History member: https://www.youtube.com/simplehistory/join
Support us on Patreon: https://www.patreon.com/simplehistory

Copyright: DO NOT translate and re-upload our content on Youtube or other social media.

SIMPLE HISTORY MERCHANDISE

Get the Simple History books on Amazon:

https://www.amazon.com/Daniel-....Turner-%60/e/B00H5TY

T-Shirts

https://teespring.com/stores/s....imple-history-offici

Simple history gives you the facts, simple!

See the book collection here:

Amazon USA

http://www.amazon.com/Daniel-Turner/e/B00H5TYLAE/


Amazon UK
http://www.amazon.co.uk/Daniel....-Turner/e/B00H5TYLAE


https://www.facebook.com/Simpl....e-History-5494376751

https://twitter.com/SimpleHistoryYT


Credit:
Created by Daniel Turner (B.A. (Hons) in History, University College London)
Script: Dejan Milivojevic
Narrator:

Chris Kane
https://vocalforge.com/

Sources:
Antill, Peter D., and Peter Dennis. Stalingrad 1942. Osprey Pub., 2007.
Roberts, Geoffrey. Victory at Stalingrad the Battle That Changed History. Longman, 2002.
Walsh, Stephen. Stalingrad 1942-1943: The Infernal Cauldron. Simon & Schuster, 2000.

Decompose an irregular shape to find area of entire figure.

Watch the next lesson: https://www.khanacademy.org/math/pre-algebra/measurement/perimeter/v/introduction-to-perimeter?utm_source=YT&utm_medium=Desc&utm_campaign=PreAlgebra

Missed the previous lesson? https://www.khanacademy.org/math/pre-algebra/measurement/area-basics/v/comparing-areas-of-plots-of-land?utm_source=YT&utm_medium=Desc&utm_campaign=PreAlgebra

Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway. You're the airplane and algebra is your sunny vacation destination. Without the runway you're not going anywhere. Seriously, the foundation for all higher mathematics is laid with many of the concepts that we will introduce to you here: negative numbers, absolute value, factors, multiples, decimals, and fractions to name a few. So buckle up and move your seat into the upright position. We're about to take off!

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to KhanAcademy’s Pre-Algebra channel:: https://www.youtube.com/channe....l/UCIMlYkATtXOFswVoC
Subscribe to KhanAcademy: https://www.youtube.com/subscr....iption_center?add_us

Hemophilia is an X-linked recessive disorder. The blood of a hemophiliac lacks the ability to clot, due to the fact that one or more of the plasma proteins required to form a clot is absent or reduced in their blood.
A recessive gene, it is carried on the female chromosome X . Males possess XY chromosomes and females XX. Since females have two X chromosomes, they are more often than not carriers.

If you look at the Punnett Square you can see the following.
Each child of a carrier will have a 50% chance of inheriting hemophilia. The daughter of a male haemophiliac will always inherit the disease, while a son cannot ever inherit it. A female will only be affected with haemophilia in the rare circumstance that she inherits mutated X chromosomes from both a hemophiliac father and a carrier mother. No case of such double inheritance is known among Queen Victoria's descendants.
Correction:
1:47 I made a mistake. The H in the lower right box should be lower case h and not a capital letter. H