AccuWeather School: Week 2

📓 April 17 – Homework: Ahh, the smell of rain ... but what are you actually smelling?

For your homework this weekend -- if it rains in your area, go outside and take a deep breath through your nose. Does it smell nice? So many people like that smell that there are rain-scented laundry detergents and candles. It may surprise you that you aren’t really smelling raindrops. You are actually getting a whiff of dirt, worms and other things in the ground.

Here’s another big word to impress your parents and teachers with -- petrichor. That’s the scent that fills the air as raindrops hit the ground. It’s caused by oils from plants, mainly leaves, that settle onto soils or pavement over time. The more time that passes between rain events, the more the oil will build up and the stronger the scent.

Don’t forget when you head outside to smell the rain, grab an umbrella or raincoat or you’ll get soaked!

📚 April 17 – Study Hall: It’s a bird, it's a bat, it's smoke (wait, what?!?) on a weather radar

You know that weather radars are used to track rain, snow and ice, but animals and other objects have even shown up. In February, a large flock of birds was seen flying over Key West, Florida. Last June, ladybugs showed up as a massive green blob on the radar over Southern California. Radar may pick up the smoke of a large fire.

“Radar works by sending a pulse of energy through the atmosphere, and when that pulse of energy encounters an object in the atmosphere like a raindrop, some of that energy in the pulse will bounce back to the radar itself,” AccuWeather Meteorologist Brian Lada said.

The chances of a weather radar detecting animals, bugs or smoke are higher when the weather in the area is dry. If meteorologists aren’t sure if they are seeing rain or animals, there are extra tools they can use to figure that out.

🎶  April 17 – Music class: Soothing sound of falling rain

Do you enjoy listening to rain falling outside? Does it help you go to sleep? You will hear many people say that the perfect sleeping weather is when it is cloudy and rainy. Obviously, a loud boom of thunder will quickly wake you up!

What else outside can make you feel calmer? Taking a stroll along an ocean, lake or river or even swimming and surfing. It’s called a “blue state of mind” when you feel really relaxed after enjoying one of those activities.

🔬 April 17 – Weather Lab: Time to make rain gauges

Measuring snowfall is as easy as sticking a ruler into the ground – but the same can’t be done with rain. Instead, meteorologists use a rain gauge to record how much rain has fallen.

You can make your own rain gauge at home with a clear cylinder, masking tape, ruler, and pen. If you are having trouble finding a clear cylinder, like the ice tea pitcher shown in the video below, ask your parents if they wouldn’t mind cutting a soda or water bottle in half. As long as they are okay with it, that works too!

Once you build the rain gauge, watch for any rain in the forecast and record how much falls. Be sure to put something around the rain gauge to provide it support so it doesn’t get knocked over by any wind.

🛎 April 17 – Morning Bell: Meteorologists look for doughnut holes on radar, and not for a snack!

Your mouth may water when you see doughnut holes, but meteorologists can get a big clue about the weather when they see something that looks like a doughnut hole on radar.

Think of times when you have seen green on weather radar showing precipitation over your home. You can look outside, and it is raining, right? At other times, red on radar will depict heavy rain, blue shows snow, and pink is ice. However, there are times when the radar will fool everyone but meteorologists into thinking that it is raining or snowing when, in fact, it is not. Meteorologists keep an eye out for a doughnut hole on radar, much like what you see in the image below.

A doughnut hole on radar typically means that the rain or snow falling out of the cloud is not reaching the ground. The air is too dry near the ground, and the rain or snow will evaporate (big word time - this is called virga). In the above image, the radar is right in showing no rain or snow around Des Moines, Iowa. The problem is that the radar beam is angled up higher in the sky the farther away from Des Moines, so it thinks it is seeing rain or snow when nothing is actually reaching the ground.

Do you see any doughnut holes on your local radar or just real ones in your fridge?

📓 April 16 – Homework: Create a mini lightning bolt at home

Since we can’t make our own hail at home, let’s wrap up this lesson plan by creating a mini lightning bolt at home. This is one lightning strike you don’t have to run and seek shelter from.

All you need is a balloon, compact fluorescent lightbulb (CFL) and someone willing to let you rub the balloon on their head.

As AccuWeather Senior Meteorologist Jason Nicholls demonstrates below, rub the balloon on your or someone’s head to build up a static charge. Then, hold the balloon to the metal tip at the end of the lightbulb. Don’t blink as you should see the lightbulb briefly flash like a mini lightning bolt. This experiment works best when the air is drier so you can build up that static electricity.

🌎 April 16 – History Class: World’s largest hailstone weighed more than 1 liter of soda

South Dakota holds the record for the largest hailstone in the United States, but the all-time heaviest hailstone was measured in Bangladesh on April 14, 1986. It weighed 2.25 pounds (more than a 1-liter bottle of soda) and likely came crashing down to the ground at 90 mph. A total of 92 people were killed during this hailstorm.

China, Russia, India, and northern Italy are other parts of the world that have endured damaging hailstorms. In the United States, there are three states where hail falls more frequently than in any other state. Find out where this “hail alley” is by listening to the weather history podcast below.

📚 April 16 – Pop quiz! In which American state did volleyball-sized hail slam down in 2010?

If you guessed South Dakota, you are correct!

A hailstone with a diameter of a whopping 8 inches hit Vivian, South Dakota, on July 23, 2010. That’s about the size of a volleyball and is the largest hailstone on record in the United States. This hailstone also weighed about 1.94 pounds!

Look at the image of the record hailstone below – it looks more like a volleyball with spikes. As a hailstone tumbles around in the air, it takes on different shapes from being smooth to jagged. The bigger the hailstone is, the more likely it will look like a ball with spikes instead of something that will roll nicely on the ground.

🍎 April 16 – Snack Time: Hail comes in sizes of peas, grapefruits, even larger!

If hail falls in your backyard, you can use common items around your home to measure its size – that’s what meteorologists do.

It may look like tiny peas are covering your yard when the smallest hailstones fall from a thunderstorm. In some of the most extreme cases, it may look like baseballs, softballs and grapefruit are blasting down from the sky. Hail of this size is extremely dangerous and can be deadly to anyone who isn’t inside a sturdy building.

Be sure to wait until after the thunderstorm has passed to go outside and grab a hailstone to measure it. While it may melt some and not be quite as big as when it first hit the ground, it’s not worth getting hit in the head with more hail or struck by lightning.

🛎 April 16 – Morning Bell: What does hail have in common with a tree trunk?

Hail is among the dangerous weather produced by severe thunderstorms. Hailstones are essentially ice chunks, but we see them more in the warmer months rather than the winter. Why is that? The answer: The air way up in a thunderstorm is below freezing.

Once hail forms, it will take a ferris wheel ride within the thunderstorm cloud. Air rushing from the ground into the thunderstorm kicks off the hailstone’s ride by pushing it up higher into the cloud. When it gets to the top of the cloud, gravity takes over and sends it back toward the ground. If the rising air that first pushed the hail upward is strong enough, the hailstone will keep going around and around the thunderstorm cloud until gravity wins out.

“Due to this up-and-down motion in the cloud, a hailstone that is cut in half will commonly have rings of ice, similar to tree rings,” AccuWeather Meteorologist Renee Duff said. The more times the hail goes around a thunderstorm cloud, the more rings and bigger it will get.

📓 April 15 – Homework: Take a gorgeous sunset photo

For this evening’s homework assignment, go outside around sunset and take a pretty photo of the sky. If there are some clouds around that aren’t covering up the setting sun, you could be in for a real treat.

“Sunlight is made up of all the colors of the rainbow,“ said AccuWeather Meteorologist Renee Duff. As the sun dips down on the horizon, the sunlight must travel farther to your eyes than during the day. “This causes the blue light that is seen during the daytime to be scattered away from our eyes, allowing more orange and red light to pass through,” Duff added. Any clouds will show off those vibrant colors to make for a spectacular photo.

If there is any ash or smoke in the air from a far-away erupting volcano or wildfire, darker shades of orange or red, or even purple colors would be drawn out from the sunlight.

If your parents say it’s OK, send us your sunset photos through Twitter or Facebook with the hashtag #AccuWeatherSchool. As a reminder, never look directly at the sun as it will hurt your eyes!

🌎 April 15  – History Class: “Perfect storm of calm” played role in sinking of the Titanic

The Titanic sank in the frigid waters of the northern Atlantic Ocean during the early morning hours on this date in 1912 after striking an iceberg.

While we have been learning about clouds today, there was not a cloud in the sky that fateful night. Even the moon was absent. The stars, however, were shining so brightly that historian and Titanic expert Tim Maltin told AccuWeather that people on the Titanic could see what time it was on their watches!

Maltin said that “it was a perfect storm of calm” that played a role in the sinking of the Titanic. Listen below to learn more about that night and how the weather system that impacted the Titanic also played a role at the first baseball game ever played in Fenway Park:

🎨 April 15  – Art Class: Make a pretty cloud collage with cotton balls

Let’s get artistic and make a pretty picture based on the types of clouds we learned about earlier. All you need for this art activity is a piece of construction paper (any color will do, but think about what color the sky is), cotton balls, glue (glue sticks tend to work best) and a pen.

Using the image below as a guide, glue cotton balls to the paper to represent cirrus, cumulus, cumulonimbus and stratus clouds. Real cumulus clouds in the sky look like cotton balls, so this activity is definitely fitting! Since cumulonimbus clouds are bigger cumulus clouds that tower way above our heads, this cloud should cover almost half of your paper.

For the wispy cirrus clouds high in the sky, you will want to pull the cotton balls apart before gluing them to the top of your paper. Stratus clouds hang low near the ground, so make them look like a blanket toward the bottom of your masterpiece.

After you are done, label the different clouds and put your artwork on the fridge!

If your parents say it’s OK, send us your cloud artwork through Twitter or Facebook with the hashtag #AccuWeatherSchool.

📚 April 15  – Study Hall: Clouds wouldn’t exist if it wasn’t for lots of this classical element

Clouds come in all different shapes and sizes, but they all need one basic ingredient to form – water.

Water evaporating from the ground, lakes, streams, and oceans rises into the air above our heads as water vapor. As the air with the water vapor continues to rise, the air cools and condenses into water droplets on extremely tiny specks of dust, smoke, pollen or salt floating around in the air. If you want to impress your parents with a big word, these tiny specks are called cloud condensation nuclei.

Think of times when you woke up in the morning to dew on the ground. It didn’t rain overnight, but water droplets formed on the blades of grass. Now imagine that happening way above our heads as billions of tiny water droplets are forming and teaming up to form a cloud.

🛎 April 15 – Morning Bell: Waves, horseshoes in the sky? Those are cloud names!

Clouds can give meteorologists a clue as to what weather will happen, it just depends on what type of cloud they see – and there are several types:

• Cirrus - These are the wispy clouds that you see high in the sky and the first to mix with sunshine when a storm is approaching.
• Cumulus - They look like cotton balls in the sky and have flat bottoms. When you see one of these clouds grow and look angry, watch out for a thunderstorm and nasty weather.
• Stratus - These clouds have a layered or blanket look in the sky or even on the ground since fog is a type of a stratus cloud.
• Nimbus - They produce rain, snow, ice or any other precipitation.

From the four types of clouds above, there are many more cloud names, and some names may seem odd for a cloud. Shelf, wave, horseshoe -- yup, those are all actual cloud names! Check out what a wave cloud looks like and how they form in the video below.

Additional experiments and reporting by Jason Nicholls.

Previous classes:

AccuWeather School: Week 1

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