Name: 5 Fun Physics Phenomena
Uploaded: 2016-04-18T15:27:19.000Z
Duration: 5 min 28 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Adverbs of manner

- Five fun physics phenomena. Number one, have a friend hold a cane out horizontally

for you, or another similar object. And putting your two index fingers together, try to place

them underneath the center of mass. When they let go, you will find it doesn't normally

work. But now try putting each index finger at opposite ends of the cane, and then moving

your index fingers in towards the middle. What you will find is that they always end

up right under the center of mass of the cane. You can try starting off asymmetrically and

they will still end up under the center of mass. You can try going at different speeds.

Really slowly, or really fast. But you still end up perfectly under the center of mass.

How does this work? Number two, the phone flip. Have you ever tried to spin your phone?

If you do it in this direction, it's pretty easy. It stays nicely aligned. If you spin

it along its short axis, you'll also find it spins very well. But if you try to flip

your phone end over end like this, you can't do it cleanly. The phone will never flip simply

end over end without also rotating in one of the other directions. Even when I make

an almost perfect flip, instabilities grow until the phone rotates around another axis.

Why can't... No, I still can't do it. Why is it so? Number three, you've probably seen

that if you rub a cup on your hair, you can make it electrically charged. And if you bring

it close to a stream of water, you can actually cause that stream to deflect. Now usually

this is used in chemistry textbooks as a demonstration of the polar nature of water. Water is a molecule

with a more positive side and a more negative side, and so what happens, so you're told,

is that the water molecule flips around so the positive side of the water faces the negative

side of the cup and that is what attracts the water to the cup. But this is not the

real explanation. If you have a uniform electric field, there's an equal force pulling the

positive side towards it as there is pushing the negative side away from it. And so you

can't actually do more than just turn the molecules. You would need a really, really

strong gradient in your electric field to make this work at all, and it basically is

just not going to happen from a cup. So why is the stream actually attracted to a charged

cup? That is the question. Number four, take a piece of your favorite cereal and drop it

into a bowl of water. Then using a very strong magnet, try to pull the cereal around. Isn't

that cool? So why is cereal magnetic? And finally, five, the teabag rocket. Take a teabag

and cut off the sealed end very carefully. Now dump out the tea. Form the teabag into

a square column. And balance it on the plate. Now light the top of the teabag on fire. Try

to light it evenly on all sides. Get ready for takeoff in three, two, one. Ha, yeah!

That is the beauty of the teabag rocket. So why did that happen? So how do all of these

phenomena work? Let me know in the comments or make a video explaining any or all of them.

Or subscribe to the channel and I'll post the answers next week. I hope you enjoyed

those fun physics phenomena. I know a guy who would, the former commander of the international

space station, Commander Chris Hadfield. I'm actually hosting live events with him in late

August in Sydney and Canberra. I'm so looking forward to that. Now, the Sydney shows are

all sold out, but there are still as of now tickets to the Canberra show. So if you want

to come to that, check out the link in the description. Now Chris Hadfield actually wrote

a book called An Astronaut's Guide to Life on Earth, and I'm listening to it right now

as I travel around the world, and it is awesome because it contains great advice not only

for people who want to become astronauts, but also for everyone who wants to lead a

meaningful life here on earth. And you can download this book for free if you like by

going to audible.com/veritasium. Or you can pick any other book of your choosing for a

one month free trial. Audible is a great service with over 150,000 titles in all areas of literature,

including fiction, non-fiction, and periodicals, and so you can find virtually anything you

want there. And by going to audible.com/veritasium, they know that I sent you and they help me

out to continue making these videos for you for free. So I really want to thank Audible

for supporting me and I want to thank you for watching.