AccuWeather School: Week 4
📓 May 1 - Homework: Create a mini lightning bolt at home
Here’s a lightning strike you don’t have to run and seek shelter from – one you can make at home! 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 head or someone else’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.
⛹️♂️ May 1 - Recess: Forget what you’ve been told – heat lightning does not exist
“You’re lying” – is that what you are thinking? It’s a mostly clear summer night and you see flashes of lightning off in the distance – you’ve been told that’s heat lightning. Actually, what you are seeing is just a really far away thunderstorm.
Thunderstorms can tower up to 6 to 10 miles (9.5 to 16 km) high in the sky, allowing the lightning to be seen over 100 miles (161 km) away, even above mountains. You don’t hear any rumbles of thunder since it’s unlikely the sound of thunder will travel more than 10 miles (16 km).
The term “heat lightning” may have started because people thought this phenomenon only happens when it’s hot. It is true that you see distant lightning more in the summer, but that’s because thunderstorms are more common on warm and humid summer days.
Bolts of lightning are shown striking south of San Francisco on Monday, Sept. 11, 2017. (AP Photo/Jeff Chiu)
✅ May 1 - Spelling test!
Lightning is a very common misspelled word. Many people will add an “e” or leave out the first “n”. Let’s break it down a little more so you can become an expert for your next spelling test.
Lightning - This is the correct spelling when talking about what you see during a thunderstorm.
Lightening - Means to brighten or lessen the load. You could say that lightning was lightening up the sky, but it is incorrect to write “I just saw lightening.”
Lighting - This refers to lights, such as in your home. See how it’s used in this sentence - We couldn’t wait to go and see the lighting of the Christmas tree.
Once you memorize this, you will make your English teacher and favorite meteorologist very happy!
➗ May 1 – Math class: Lightning is 5 times hotter than the sun’s surface
When a bolt of lightning passes through the air, it can heat the air to 50,000 degrees Fahrenheit. That is about five times hotter than the surface of the sun. Also, compare that to the current temperatures around your home – talk about hot!
To understand how lightning forms, think of a simple battery in your home. One end of the battery has a + for a positive charge, and the other is labeled with a - for a negative charge. Within a thunderstorm, there are numerous positive and negative charges. When the difference between these charges increases to a certain point, you get a significant spark of electricity in the form of a lightning bolt.
Lightning doesn’t just strike the ground. There are lightning bolts that never leave the sky. You may see lightning streak within its own thunderstorm cloud or strike another neighboring cloud. One thing to remember is that when you hear thunder, run indoors to avoid being struck. When something can heat the air to a temperature hotter than on the sun, you know that it’s very dangerous!
🛎 May 1 – Morning Bell: ‘Bolt from the blue’ is not a painting, but very dangerous lightning
Let’s start this class with a pop-quiz – When is it safe to head back outside after a thunderstorm?
If you said 30 minutes after you hear the last rumble of thunder, you get a gold star!
You should wait that long to make sure a very dangerous “bolt from the blue” will not occur. This lightning bolt typically comes out of the back of a thunderstorm but doesn’t strike the ground underneath the cloud. It travels straight across the sky for some time before arcing down and hitting the ground. There have been cases where a “bolt from the blue” struck the ground 25 miles (40 km) away from the thunderstorm, under a fairly clear sky!
Because it seemingly comes out of nowhere, “bolt from the blue” lightning strikes could be cases for forensic meteorologists – who investigate court cases that involve the weather. Tune to the Everything Under the Sun podcast below to hear AccuWeather forensic meteorologists tell their tales of the heat and lightning court cases they were a part of:
📓 April 30 - Homework: Freezing pants? Baking biscuits in cars? Having fun while learning!
We’ve talked about lesser-known weather terms, now let’s have fun talking about the silliest things meteorologists have done to tell you about the weather.
Here’s one way to show that the weather is frigid – freeze your pants!
Have you ever seen a meteorologist bake cookies or biscuits in a car or fry an egg on a sidewalk? While that is really cool to watch, they are trying to teach you and your parents an important lesson. If your car can get hot enough inside to bake food, is it good for you to be in that car? Definitely not!
On a sunny day in the late spring and summer, a parked car with the windows up and no air conditioning will become dangerously hotter than the air outside. Check out how hot a pan got when a car was used as an oven to make biscuits!
The inside of cars can get dangerously hot even if the air outside feels comfortable – when the outside temperature is 80 F (27 C), the inside of a parked car can soar to 123 F (51 C) in just an hour.
📚 April 30 - Study Hall: Haboobs – walls of dust that engulf towns, cities
Massive dust storm is the simplest way to describe another lesser-known weather term – haboob (pronounced “huh-boob”).
Strong winds rushing cold air out and away from thunderstorms kicks up dust and sand in desert communities to form haboobs. Haboobs can be fleeting and may only last 10 to 30 minutes, and the walls of dust and sand they kick up can grow as high as 10,000 feet (3,000 meters)!
Haboobs can definitely be a scary sight as they appear to swallow up entire towns and cities. People in those areas when a haboob hits may tell you later that it was like a dust blizzard swept through. It’s very hard to see far in front of you during a haboob – which is a very dangerous thing for anyone driving a car or truck.
🎭 April 30 - Story Time: This upside down cloud looks like a cow’s udder
The next lesser known weather term of the day – mammatus clouds – is an exception to the cloud rule. Most clouds form when air rises, cools and condenses. Mammatus clouds are backwards – and look like upside-down clouds too (check it out below)!
Mammatus clouds covered the sky at sunset in Claremore, Oklahoma, on April 28, 2020. (Facebook/Jan Brown)
“Mammatus clouds develop when air sinks,” AccuWeather Meteorologist and Digital Journalist Brian Lada explains. “The sinking air must be cooler than the air around it and have a high liquid water or ice content.”
Since the air is sinking (moving from up high in the sky to the ground), you can see why the clouds bubble downward – opposite of puffy cumulus or thunderstorm clouds that tower high in the sky! The unique look of mammatus clouds is how they got their name – do you agree that they resemble cows' udders?
Mammatus clouds are typically seen underneath a thunderstorm’s anvil (its top). Many people think that mammatus clouds mean a tornado is approaching. More often than not, it’s the opposite – these clouds form when a thunderstorm is weakening.
🎓 April 30 - AP class: Impress meteorologists with these weather terms
Let’s challenge ourselves and learn some really big weather words – you’ll definitely impress your favorite meteorologist!
Did you see the word petrichor in the video? Remember, we talked about how that is the scent that fills the air as raindrops hit the ground during a previous lesson at AccuWeather School. If you were out sick that day, you aren’t really smelling raindrops. You are actually picking up a whiff of dirt, worms and other things in the ground.
🛎 April 30 - Morning Bell: Derecho – when damaging winds are at their worse
Have you ever heard the term derecho? It’s a cluster of powerful thunderstorms with wind gusts of 58 mph (93 km/h) or greater that produces a non-stop path of wind damage over a stretch of 240 miles (386 km).
“The term derecho is derived from the Spanish language adverb which means “straight” in English,” according to AccuWeather Senior Meteorologist Alex Sosnowski. “The term tornado in Spanish means “to turn.” Makes sense – derechos produce straight-line winds. Twisting winds in tornadoes spread out the damage in different directions.
Derechos are also much bigger in size than tornadoes. Look at the radar image of the Super Derecho of 2012, it stretched across the entire state of West Virginia and traveled nearly 800 miles! The widest tornado on record was 2.6 miles (4.2 km), while the longest tornado path was 219 miles (352.4 km) – smaller than a derecho but by no means less deadly!
This radar image shows the complex of thunderstorms that was classified as a derecho as it swept from southeastern Ohio to West Virginia during the evening hours on June 29, 2012. (NOAA)
One last tidbit on derechos – they may look (at least on radar) and feel like an inland hurricane. Hopefully you never are outside during a derecho – make sure you are seeking shelter if one of these hits your community!
📓 April 29 - Homework: Watch the air set a cotton ball on fire
After a day of studying deserts and thinking about hot weather, here’s an experiment to get the air so hot that it will light a cotton ball on fire. You will need a fire syringe (many of you may have to wait until your parents’ next shopping trip), a small piece of cotton and definitely an adult to help.
Watch closely as AccuWeather Senior Meteorologist Jason Nicholls demonstrates the experiment – the fire ignites very quickly! How does it work? When air gets squeezed down in the tube, it quickly heats up to around 410 F (210 C) – the temperature needed to ignite a piece of cotton.
The air heating up as it gets squeezed in the tube is known as compressional heating. Meteorologists see compressional heating in action when a hot dome of high pressure is overhead and the air high in the sky is pressed down to the ground. The air here on Earth won’t heat up enough to light a cotton ball on fire, but people have been able to fry eggs and bake cookies on sidewalks and in their cars on really hot days!
⛹️♂️ April 29 - Recess: Wild ride temperatures take in the desert
How do deserts get scorching hot during the day, yet drop to freezing temperatures at night?
It all has to do with the sandy soil and moisture! Deserts typically have little to no clouds overhead, which makes it easy for the sun’s rays to reach the ground and heat it up. The desert sand isn’t so good at holding in heat for long (compared to concrete or soil), so the warmth is reflected back into the air and temperatures soar. This is why it gets so hot!
One example of how hot it can get is the ever-famous Death Valley, California. Situated below sea-level and close to the Sierra Nevada mountain range, Death Valley rarely sees rain. It’s known globally for recording the world’s hottest temperature ever - 134 F (56.7 C)!
When it’s nighttime, temperatures take a nose-dive. Think of the weather around your house. When it is much cooler at night than during the day? On a clear and calm night with low dew points, right? That happens often in the deserts and is known as radiational cooling!
Another awesome thing about deserts is that they make a great spot for looking at the stars! Since there are no clouds there to block the view, it is a perfect place for astronomers to visit with their telescopes for sky watching.
🌎 April 29 - History Class: Even typically hot deserts have seen snow
It definitely doesn’t happen often, but snow has fallen in the typically hot deserts around the world – are you picturing camels playing in the snow like your dog would?
Rare snow happens when really cold air plunges southward with a storm. That was the case back in early January 2018 when snow blanketed the Sahara Desert north of Algeria’s city of Ain Sefra. This area actually saw snow four times between 2012 and 2018!
For the kids reading this, none of you were alive the last time snowflakes were seen in Phoenix, Arizona, – that happened on Dec. 6, 1998. There wasn’t enough snow to measure, but what a sight for everyone! You have to go back to a few days before Christmas 1990 when there was just enough snow to make a snowball (0.4 of an inch).
While snow doesn’t fall often, there are other weather events that are unique to deserts. Have you ever heard of a haboob? Ha what? It’s a real hazard in the desert. Tune in to AccuWeather’s Everything Under the Sun podcast below to learn more:
🍎 April 29 - Snack Time! What blocks the rain from reaching the deserts?
Look at the satellite image below and the areas (highlighted in dark red) where there aren’t many clouds. It’s no coincidence that most of the world’s deserts are in these corridors.
Think back to our lesson on how the air rises around low pressure systems (storms) and leads to rain or snow, while dry weather is in control near high pressure as the air way above our heads sinks down to the ground.
The deserts formed long, long ago because the air takes a much bigger roller coaster ride up and down across the entire globe. In the red zones in the map above, sinking air limiting clouds and rain is common. Notice, there are many more clouds in between and on either side of these corridors – the air tends to rise here with frequent storms. Check out that band of clouds in the center of the map. That’s roughly where the equator is, and it’s a stormy place!
🛎 April 29 - Morning Bell: Largest desert in the world? Not the Sahara!
Picture the largest desert in the world – are you imagining sand, camels and blazing sunshine? The sun shines on the largest desert in the world, but not all year long and there definitely isn’t sand or camels there. Where’s that? Antarctica!
A desert doesn’t have to be a hot location. Any area that receives little or no rain (or snow) and cannot provide a good natural home to many plants or animals is a desert – that’s Antarctica.
The Sahara Desert is more like the typical desert you may have imagined. The Sahara is the largest desert outside of the poles (the cold tops and bottoms of the Earth), and its sand and dust don’t sit still. The sand and dust can prevent hurricanes from forming in the Atlantic Ocean and have caused snow-covered mountains in Europe to turn orange – like a scene from Mars!
No people or plants are seen in this photo of the Sahara Desert. (Photo/Teddy Minford)
📓 April 28 - Homework: Rainbow hunting time!
The perfect time to look for a rainbow is after school and before the morning bell.
“[Sunlight] has to pass through the water droplets at a low angle to make a rainbow,” according to AccuWeather Senior Meteorologist Dave Samuhel. From sunrise to mid-morning and then again from late afternoon to sunset are the best opportunities for you to see a rainbow. The sun is too high in the sky around lunchtime for a rainbow to form.
A double rainbow paints the sky over central Pennsylvania on April 27, 2015. (Facebook/AccuWeather Senior Meteorologist Dan Pydynowski)
So, why do you tend to see rainbows more after school than when you are headed to school in the morning? Clouds typically blanket the sky when rain falls in the morning, and no sun can peek through. Later in the day during the warmer months, rain usually comes from showers and thunderstorms that tend to hit your house and miss your friend’s home - with breaks of sunshine in between.
Did you have a successful rainbow hunt? If your parents say it’s OK, send us your rainbow photos through Twitter or Facebook with the hashtag #AccuWeatherSchool.
⛹️♂️ April 28 - Recess: What’s really at the end of a rainbow?
You see the end of a rainbow in your friend's backyard and call to say there’s a pot of gold in the family’s yard. Your friend heads outside and looks for the gold, but the rainbow will look even farther away from her.
Rainbows aren’t solid objects. They are optical illusions – something your eyes can see but you can’t touch. If you try to run toward a rainbow, it will seem like it keeps moving away from you!
If your same friend that you called earlier was flying in an airplane over her house, she may never see a rainbow’s end. To those of us standing on the ground, most rainbows look like an arc because the ground gets in the way. People in planes or in skyscrapers may see the rainbow as a full-circle.
A rare circular rainbow was seen over Lake Argyle in Western Australia on Feb. 5, 2020. (Video still image/Colin Leonhardt)
🔬 April 28 - Weather Lab: Rainbow-making time!
Making a rainbow at home is pretty easy. If it’s sunny outside, spray a garden hose (not at a sibling!) with the sun at your back and watch a rainbow form.
You can even create a rainbow inside with only a flashlight and a CD (your parents should have one from the 1990s). Shine the flashlight on the back of the CD and play with the angles until you see the display of colors. By adjusting the angles, you are causing the light to bend in a way that is necessary for a real rainbow to form outside. This experiment works best in a dark room with a white wall.
Once you are done with this experiment, AccuWeather Senior Meteorologist Jason Nicholls shows you how to make another rainbow at home with a few more simple items.
🎨 April 28 - Art Class: Recipe for one of Mother Nature’s artwork masterpieces
The recipe for a rainbow is simple – you need falling water and sunlight. As the light passes through the water droplets, it gets refracted - meaning it takes a bounce like on a trampoline inside the water droplet and bends back toward the sun (that is why you will always see the rainbow with the sun behind you).
If a rainbow is bright enough, you may be treated to a double rainbow. That happens when the light takes two bounces on a trampoline inside the water droplet. The result is a faded rainbow with the color pattern flipped. For the main rainbow, red is always on the outside edge of the arc, followed by orange, yellow, green, blue, indigo and purple (you know the phrase “Roy G. Biv”). Check out a double rainbow the next time you see it – the colors are backwards!
🛎 April 28 - Morning Bell: What does a rainbow have in common with a dog?
Have you ever looked up in the sky and noticed a patch of rainbow, but it wasn’t raining? That’s actually a sundog!
A sundog forms on cirrus clouds, which are the wispy clouds way up in the sky that are made of ice crystals. Much like how the light bounces off and bends away from water droplets to make a rainbow, sunlight will mimic that behavior with ice crystals.
A sundog, circled in red, was seen over State College, Pennsylvania, on June 19, 2018. (Twitter/AccuWeather Meteorologist Becky DePodwin)
Sundogs are also called mock dogs or parhelia, which means “with the sun.” That makes sense once you know that sundogs are usually found at the same distance away from the sun either to its left, right or on both sides. Next time you are outside and it’s sunny, extend your arm out and cover up the sun with your thumb (remember don’t look directly at the sun!). Now hold out your little finger – that’s around where you will see sundogs. Like your pet dog, this “dog” in the sky is not far from the sun!
If you see more than a patch of rainbow, you might be treated to a rare circumhorizontal arc. Sometimes, halos around the sun or moon can also have color.
📓 April 27 - Homework: Crush a can with ocean-like strength
For most of you reading this, there is 14.7 pounds per square inch of pressure from the air pushing on you. Don’t feel it? That’s because your body is pushing back with the same force. However, if you took a very deep dive into the ocean (not recommended), the water pressure would be strong enough to break your bones.
Since we don’t want to see anyone break their bones, here’s one experiment where air pressure can crush a can. You must have an adult help you with this experiment, but it is easy to do with an empty soda can, water, ice, tongs, potholder, and a stove.
When AccuWeather Senior Meteorologist Jason Nicholls puts the hot can in the ice water, the steam inside the can quickly cools and condenses into water. That lowers the pressure inside the can so much that the air pressure outside crushes it.
📚 April 27 - Study Hall: All hail the king of the ocean tides
No matter what beach you head to, you will always hear crashing waves – thanks to gravity from the moon and a little from the sun. While this gravity isn’t strong enough to pull you into space, it tugs on Earth’s oceans and causes typically two high tides and two low tides a day.
King tides are the highest tides of the year. The higher the tide, the more water will get pushed up onto the beach and can cause flooding.
The highest tides in a month occur around the new and full moon. If these moon phases happen when the moon is closest to the Earth in its orbit, a phenomenon known as a supermoon for the full moon, there can be even higher tides. If all of that happens when Earth is closest to the sun (which is during winter in the Northern Hemisphere), the highest tides will pound the beach.
It’s not just gravity from the moon and sun that can stir up waves – strong winds will also do that.
🎨 April 27 - Art Class: Know these flag colors before heading to the beach
Lifeguards and the different colored flags on their stands are there to keep you safe from dangerous waves, rip currents and even animals in the ocean. So let’s see what each flag color means:
🟩 - Green means go and low dangers to you.
🟨 - Take caution with yellow. There is not enough danger for lifeguards to keep you out of the water, but the ocean may be a little too rough for some people to swim safely.
🟥 - We all know what red means – stop. You shouldn’t go in the water since waves and rip currents are too strong. You can still play all day in the sand!
🟥🟥 - If red is bad, double red is even worse. When you see two red flags, the ocean is closed and you are not allowed in. People can even get arrested for trying to go for a swim since it is so dangerous. If you see black squares in the middle of both red flags, a hurricane warning is in effect.
🟪 - Purple has nothing to do with the weather and water conditions. This flag lets you know that jellyfish, stingrays, sharks or other dangerous fish have been spotted. Speaking of jellyfish, vinegar can help if one stings you.
📝 April 27 - Pop quiz! How many quadrillion gallon-sized milk jugs can Earth’s oceans fill up?
352,670 quadrillion! What’s a quadrillion? Let’s see that number with all of the zeros: 352,670,000,000,000,000,000 - our friends at NOAA get an A+ for that math!
Humans need to live on land, but there is way more water on Earth. Here’s some facts to learn for your next pop-quiz:
Water covers 70 percent of Earth
Out of all the water on Earth, about 97 percent is in the oceans
The Pacific Ocean is the largest of the four oceans on Earth
The longest river in the world is the Nile in Africa
The Mississippi River is not the longest river in the United States. The Missouri River beats out the Mississippi by 200 miles!
Water makes up about 60 percent of you
Water is very important to weather. Water evaporates from puddles, lakes and oceans. As that water vapor rises up in the air, it cools and condenses and forms clouds. Rain, snow and thunderstorms will follow if there’s enough moisture. What we just described is the water cycle!
🛎 April 27 - Morning Bell: How do fish stay safe from lightning?
You are swimming in a lake or the ocean and you hear thunder. You jump out and get indoors, right? But what about the fish still in the water, how do they stay safe?
As long as the fish aren’t swimming near the surface, they are usually safe from a lightning strike. Remember that lightning forms when there is a significant difference in positive and negative charges (think of a battery) within a thunderstorm cloud or from the cloud to the ground. On a lake or ocean, the electrical charge to spark a lightning strike is along the water’s surface.
Lightning strikes near Ludington, Michigan, on June 30, 2014. (AccuWeather Fan "flaminius")
It’s unknown how deep the lightning strike will reach in water, but most fish swim deep in lakes and oceans and can ride out thunderstorms there.
So if lightning strikes don’t travel deep in bodies of water, why isn’t it safe for you to take a shower or bath during a thunderstorm? It’s the metal that your water pipes are made of that can carry the electricity from lightning to a bathroom. Listen to a time when lightning caused half of one town to lose its water supply in the Weather History podcast below:
Additional experiments and reporting by Jason Nicholls.
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