The Science Behind How We See Rainbows

 

What's up, sunshine!

 

Welcome to beautiful San Antonio, Texas.

 

We are on the beautiful Riverwalk,

 

cruising along with our friends at Go Rio Cruises.

 

And my captain, this is Captain Joel.

 

He's been doing this 33 years now. That is awesome!

 

Welcome to CNN 10, I'm CoyWire.

 

We want to give a big congrats to the University of Connecticut the Huskies,

 

locking up their 12th NCAA women's basketball championship

 

in an impressive win over South Carolina.

 

And on the men's side last night, right here in San Antonio,

 

it was the Florida Gators coming out on top

 

with their big win over Houston.                    

 

So congrats to them as well.

 

All right, let's get you your news.

 

We start today with some of the dangerous spring weather

 

that we're seeing across the southern US and Midwest.

 

Destructive storms unleashed relentless rain

 

and produced tornadoes over the weekend,

 

and they've only begun to subside at the beginning of the week.

 

subside[səbˋsaɪd]v. 消退；消失；平静下来，平息

 

Across the central US, the National Weather Service logged

at least 58 tornadoes since the storms began.

 

Those storms dumped over a foot of rain

across the Mid-south since last week.

 

Over the weekend, more than a dozen daily rainfall records

 

were set in Arkansas and Tennessee.

Memphis saw its wettest day ever in April

with more than 5 inches of rain.

Although the rain has stopped,

communities are not out of danger as rivers continue to rise.

 

Widespread flooding has triggered evacuations,

water rescues, and warnings to move to higher ground

across Kentucky.

 

The Kentucky River is predicted to crest

 

crest [krɛst] v. 达到顶点

 

at a new record of 49 and a half feet,

 

the highest level it's reached since flooding in 1978.

 

Kentucky's governor declared a state of emergency last week

and urged residents statewide to take the flood threat seriously.

 

Pop quiz hot shot: Weather balloons carry what instrument

used to measure the atmosphere?

 

Barometer, radiosonde, thermostat, or anemometer?

 

barometer [bəˋrɑmətɚ] n. 气压计

radiosonde [ˋredɪo͵sɑnd] n. 無線電高空測候器；無線電探空儀

anemometer [͵ænəˋmɑmətɚ] n. 【氣】風速計

 

If you said radiosonde, rise up!

It's a small battery-powered instrument

suspended below a weather balloon,

 

gathering atmospheric data like temperature, pressure, and humidity,

then transmitting that info to a ground receiver via radio.

 

The National Weather Service has been launching weather balloons

and their attached radiosondes to make upper atmosphere observations

since the 1930s.

 

And while other methods like Doppler radar, satellites,

and aircraft observations help in this effort,

 

the National Weather Service considers weather balloons

the best method for measuring weather factors

like humidity, wind, and pressure

for building accurate weather forecasts.

 

So what happens if some of these balloons,

launched twice a day from more than a hundred sites across the US,

no longer take flight?

 

Our meteorologist Allie Chinchar has more.

We are at the National Weather Service office.

We're going to be running through a weather balloon launch today.

 

There are roughly 100 National Weather Service offices

scattered across North America and the Pacific Islands.

 

And they're all roughly evenly spread out

so that you get good coverage when you're trying to

give forecasts for a specific area.

 

All of these dots here represent a site

that offers weather balloon launches twice a day, every single day.

 

The yellow dots indicate a location

that's gone down to just one launch per day

instead of the usual two.

 

The red dots indicate where they have gotten rid of the launches entirely.

Our particular weather balloon here is filled with hydrogen,

which is then attached to an instrument called a radiosonde

 

that measures temperature, humidity, pressure, as well as wind speed

as it moves up in the atmosphere.         

 

Uh, one of their core functions is that the data

that we take from them twice a day is used and ingested

into weather models that produce the forecast that you, say,

get on your phone or are utilized by your local or national TV meteorologist.

 

They can also be used in the event of severe weather.

Sometimes on extremely windy or stormy days,

it actually can take two or even three

National Weather Service employees to launch the balloons.

 

Oftentimes when you have a tropical system

that is nearing landfall or a severe outbreak

that is expected, many of these offices

will actually issue extra balloon launches,

perhaps one or even two more per day.

 

Now we're actually cutting back on the weather balloon launches

rather than adding more in times that we really need to have the extras.

 

All right, so far in today's episode,

we have talked about storms and the best ways to predict them.

 

But, what about some of the beauty that comes after the storm?

 

Sometimes we see those rainbows, right?

 

And it turns out this everyday marvel is more complex than you think.

We all know that no two people are exactly the same.

 

And it turns out no two people will ever see the same exact rainbow

in the same way.

 

Why? We humans each see our own unique set of reflected light

from different raindrops from our own very different perspectives.

 

Our Meg Terrell talks to a professor

of atmospheric sciences to help explain this fascinating phenomenon.

 

Did you know that no two people see the exact same rainbow?

 

Each person sees their own rainbow.

 

These amazing displays of nature are different for everybody

because they're created by sunlight refracting through raindrops

and then reflecting back out.

 

refract [rɪˋfrækt] v.【物】（使）折射

reflect [rɪˋflɛkt] v. 反射

 

And we all see reflections from different drops.

According to atmospheric scientist Dr. Steven Businger,

 

it seems like you're seeing the same rainbow,

 

but in as a matter of physics, you're actually seeing different rainbows

 

because you have a different perspective, slightly different perspective.

 

So the rainbow's being made up of different raindrops.

We all know what it takes to make a rainbow:

 

sunshine and rain at the same time.

 

But what's actually happening?

Businger says is that as sunlight hits the droplets,

it bends or refracts.

 

And because colors travel at different wavelengths,

the bending reveals them to the human eye.

 

The wavelength of blue light is shorter than the wavelength of red light.

And the energy associated with the blue light is higher

than the energy associated with the red light.

 

And so the blue light tends to be bent more than the red light.

And each raindrop is actually reflecting only one color back to us.

We see red on top of a rainbow and blue on the bottom

 

because their different wavelengths mean they exit the raindrops at different angles.

 

exit [ˋɛksɪt] v. 离开

 

Each raindrop in the shower is producing one color for your eye,

 

and then you go to the next raindrop and it produces another color.

 

And in some that gives you the whole rainbow.

If you're very lucky, you might see a double rainbow.

 

It's a second reflection at the back of the drop

 

so that the light comes out at a higher angle.

 

Or on a bright moonlight night, if you go out at night

 

and there's a full moon and you look away from the moon,

 

there are times where you can see a rainbow, or a moon bow,

 

I guess it's called at that point.

 

But Businger's favorite rainbow fact is that you'll never find the end of a rainbow.

If you're in a helicopter or a small plane,

you can see a full circle rainbow

 

because the rain doesn't hit the ground and it creates a full circle.

 

So no pot of gold, but now you know some physics,

and that's everyday science.

 

the pot of gold at the end of the rainbow 海市蜃楼; something that will be very difficult to achieve in reality, although you dream of getting it

 

Today's story getting a 10 out of 10:

 

An offline club ditching screen time for IRL time.

 

The offline club started in Amsterdam in the Netherlands,

 

offering a space for folks to take a break from their screens

 

and all the distractions that keep us plugged in, scrolling,

 

and those sorts of things, and missing more in-person connections

with the people around us.

 

Now there are offline club chapters in cities around the world,

from London to Lisbon to Dubai,

 

chapter [ˋtʃæptɚ] n.【美】（俱乐部、协会等的）支部，分会

 

where people of all ages are coming together for screen-free fun.

 

Take a look. My name's Ben Hounsell, and I'm city leader for the offline club London.

We're pioneering a movement to help people swap screen time for real time.

It was founded by three Dutch guys in Amsterdam in February 2024,

 

just a group of friends trying to get away from their phones.

 

And since then, it's really grown into a global movement.

So it's just a phone-free event.        

 

You turn up, you hand your phone in at the start,

 

and for the next 2 hours you're offline.

 

We'll have live music, live piano,

 

and then people will pick up those forgotten hobbies: reading, journaling, writing.

 

It's really mindful.

 

I'm not anti-tech myself.

 

I think it's just very beneficial to get away from tech for a few hours.

 

So I'm 23 years old. In my previous startup,

 

I was spending hours upon hours a day

 

optimizing video for Tik Tok, making sure it was as addictive as possible.

 

optimize [ˋɑptə͵maɪz] v. 使完美；最佳化;  優化

 

Ironic, right? I think for us as humans,

 

it's about discovering what parts of these phones do that we want to use for good

 

and what parts aren't benefiting us.

 

Our core audience is actually 90% female, ages 25 to 50.

 

So it's not actually really Gen Z and Gen Alpha

that are coming to these events.

 

I think they're just the most addicted to their phones.

 

We got weaker real-world connections.

 

It's really declining our mental health.

 

My pep talk would just be to come to an offline event.

 

pep talk 鼓舞士气的谈话，激励性谈话

 

Come and chat to me there in person,

 

and I reckon I could convince them to go offline for a bit.

 

All right, I want to give one more thanks to my captain Joel.

 

Appreciate you, sir.

 

And we're going to make this a two shout-out Tuesday.

 

This one goes to the Cougars at Haddam Killingworth Middle School

in Killingworth, Connecticut.

 

Thank you for subscribing and making us part of your day.

 

And this one goes to John J High School and all our Mustangs

right here in San Antonio. We see you, Coach A.

 

Remember tomorrow's #yourword Wednesday.

 

You know the drill. Submit your unique vocabulary word and definition

along with your school's name, and we'll choose one fun winner

to work in tomorrow's show. Let's go!

 

And yee-haw y'all! Hope you float on through this day real nice.

 

yee-haw 咦呵（美式英語中表示狂喜的歡呼聲）

 

Like I'm Coy Wire, and we are

 

CNN 10.