nightly news with lester holt: kids edition." ♪ coming up, celebrating planet earth we'll explain the meaning behind earth day and what you can do to help then we've got the dirt.

these students are learning how to compost it's a big win for the environment. we're going to do lots of physical activity today in this compost class. >> also, a fourth grade class is on a mission to bring an important piece of history back to utah. >> we can bring this fight to utah police, stepping out three lion cubs just made their public debut in chicago. we're there with all the details. and golden strong. these dogs are coming together to honor one of their own and a whole lot more. >> they're so pure they're so genuine and loving. they're just the best friends. >> find out what makes this breed so special this is ""nbc nightly news" kids edition". welcome back i'm lester holt. it's great to be with you on a saturday morning hope you're having a good

weekend so far we have our kid series to lion cubs in can chicago. plus, later on we'll introduce you to this group in massachusetts making kids and grownups smile thanks in part to their lovable ways. first, let's begin with an important story. the ongoing efforts around the world to help protect the environment. today is earth day, a time to celebrate and raise awareness about planet earth there are a few simple things you can do to help protect the planet we get more now from our friend anne thompson. >> reporter: every april, billions of people around the world get together and celebrate planet earth. the first earth day took place on april 22nd, 1970. a senator from wisconsin organized the demonstration to bring attention to environmental issues by 1990, people in more than 140 countries were celebrating earth day and it's grown bigger ever

since. earth day is a day to raise awareness about protecting the planet from things like pollution. >> pollution is the introduction of harmful materials into the vi environment. for example, like trash you see on t the sidide of the road or creek, thahat's pollutution. oil or chemical skills are pollution, also car exhaust. also noise can be pollution. if there's too much sound in the ocean and the whales can't hear each other, that's considered pollution. or light can be pollution. >> reporter: then there's deforestation. >> the forest is an enormously important habitat. >> reporter: forests can absorb lots of the planet-warming gas carbon dioxide they also release oxygen for people to breathe. but when we cut trees down, much of that co2 is sent back into the atmosphere, making climate

change worse lots of human activity like driving cars powered by gasoline and people not properly disposing of garbage adds to environmental problems. >> the number of garbage trucks that americans fill each year would stretch halfway to the moon we throw a lot of stuff away >> reporter: kids like ryan hickman are stepping up. he started ryan's recycling when he was really young and has been hosting cleanup events in california and beyond for years. >> this can't be good for animals. >> reporter: ryan spoke with lester last year. >> does it blow your mind how much trash and recyclable materials can be found on a beach like this? >> yes, it does. it's saturday that people don't pick up after themselves just pick it up. it's really easy i do it all the time. >> reporter: 1 million plastic

bottles are purchased every minute and 5 trillion plastic bags are used acroskcross the g every year half of all plastic used is single use, meaning it's used one time and thrown away that thrown-away plastic can end up in the ocean and threaten all types of wildlife. >> if no one picked that up, what could happen? >> a sea turtle could think this is a jelly fish and eat it and die. >> reporter: recycling is a really important way you can help protect planet earth. >> if you wanted to celebrate eartday, one idea is to tour your local recycling center. you will learn to be a better recycler that's important because recycling not only saves energy. for example, one aluminum can recycles can power a tv for three hours. it also means you're not using

raw materials. >> reporter: another thing you can do -- >> it's almost ice cream season. one easy thing you can do at the ice cream shop is to select a cone instead of a cup. that's just saving you one piece of trash ice cream cups and spoons can be pretty harmful, especially at the beach. these pieces of trash are e so lilightweight that it's easy for them to blow into the water. it's really bad for animals to get a hold of that stuff we love to say that kids can make an impact there's so much kids can do. >> reporter: in fact, kids can do a whole lot, like walk or ride a bike rather than ask your parents to drive you, turn off lights, tvs and computers when you are not using them and you can also host or join a neighborhood cleanup. >> we just tell kids don't pick up anything sharp or dangerous

leave it alone >> reporter: and keep asking questions, so together we can do a better job of protecting the planet on the subject of protecting planet earth, some students in california are getting their hands dirty quite literally and doing their part to save the environment. it's called composting >> reporter: in los angeles, students are turning garbage into gold. here fourth graders are getting their hands dirty learning about gardening thanks to the garden school foundation, an organization teaching kids about the environment. >> let's move our bodies, because we're going to be doing lots of physical activity today. >> reporter: today they're collecting, chopping and sifting

soil to make nutrient rich compost. >> it's a lot of work. you take scraps and use it for other things. >> reporter: what exactly is exhausting and why is it important? >> composting is nature's natural way of recycling it's breaking down ingredients into usable resources for the soil around us when we throw something away, it disappears from our yard, but it has a pretty big impact on our planet if it ends up in landfill, it creates methane which is a gas that's harmful to the atmosphere and temperatures and weather patterns. >> if we compost, separate our food scraps from other trash, it can be made into helpful soil to grow more food. >> we're creating a closed loop

system from table to compost >> reporter: in order to make compost, we need to mix your left overs like banana peels and pizza crusts with dry leaves and twigs. pile them up in a separate bucket from your regular trash can. over time, billions of tiny creatures break it down to soil. it can reach temperatures up to 140 degrees. after it's broken down, it's time to sift the dirt to get rid of any unwanted steerls. >> we're getting that fine finished compost >> reporter: here in l.a. it's now required they're asking everyone to separate their green waste like fruits and veggies from other trash. curb-side pickupand these gree bins will be available to make it as easy as possible kids are doing their part.

>> at home after breakfast, there's extra eggshells. we save it for a week andevery friday we grind it with the other soil we get at home depot. so we grind it and replace it with some of the other soil we have already in the plants. >> reporter: in this class, students gather dry leaves, mashed food scraps, pile them up and sift through the dirt, greeting critters along the way. even worms play an important role how do the students feel after they compost >> i've known firsthand how empowered the students feel through this process because i've even had parents tell me that lesson you did last week was awesome. they raved about it. when they understand the full cycle of this whole thing, then they become invested. >> reporter: there are plenty of ways to compost at home. if you don't have a back yard,

you can store scraps in your freezer. that way, it keeps smells and fruit flies away you can then take your collection to a compost hub. >> you can make a small difference, but ultimately kind of a big one >> thank you so much time for our pop quiz now where we put you to the test the question this week, which state is the most biodiverse in the u.s. biodiversity refers to all living things, plants, animals and humans is it california, alaska or alabama? i'll give you a few seconds to think about it okay time's up. the answer is a, california. california is the most biodiverse state having the

largest variety of animals and plants of any state in the u.s california comes in at number one. california is also home to the tallest, largest and oldest trees in the world j just ahead, we'll introduce you to these lion cubs who just stepped out in public for the first time what you need to know about them. plus, golden moment. a special group in massachusetts came together to honor one of their pals we're there with the details we'll also tell you what makes golden retrievers so special and inspiring kids these fourth graders turned a class assignment into action and are hoping history will be on their side. >> today we're kicking off a statewide letter writing campaign. >> this will probably be the

toughest assignment i've ever done , and on main streets acrossss the e us, you'll find pnpnc b. helping bubusinesses both l large and s small, communitieies and the e peope who liveve and work k there growow and thrivive. wewe're proroud to callll these e places homome too. they're where w we puput down roooots, and where e together,, we w work to helelp move eveveryone's financiaial goalals forward.d. pnc c bank. ♪ ♪ ♪ ♪ you've done the hard part. you quit smoking. now do the easy part and get scanned for lung cancer. if you smoked, you may still be at risk, but early detection could save your life. talk to your doctor and learn more at savedbythescan.org

we really don't want people to think of feeding food like ours is spoiling their dogs. good, real food is simple. it looks like food, it smells like food, it's what dogs are supposed to be eating. no living being should ever eat processed food for every single meal of their life. it's amazing to me how many people write in about their dogs changing for the better. the farmer's dog is just our way to help people take care of them. ♪ - addressising climatete chae requireses effort frfrom all o, now anand for genenerations to come.e. - jojoin dylan a and me as we get t personalal about ththe environmnment anand how we can each do ourur part. - wawatch our coconversatin on p peacock.

welcome back toni "nightly news" kids edition there's one zoo in illinois that made headlines this week after drawing a big crowd for a special debut. check out these african lion cubs at the lincoln park zoo in chicago. they are 3 months old and just left their den for the first time to explore the outdoors joining us now with more is maureen leahy, vice president of animal care and horticulture at the lincoln park zoo great to have you on tell us about these cubs what are their names

>> we are beaming with pride about the expansion of our lion pride. we just welcomed three months ago three new african lion cubs. their names are patu, which means unexpected gift, fedi and lomilock. >> how are the cubs adjusting to being out in public? >> they are doing fantastic. they just emerged from their denning area this week the weather in chicago was warm enough they're just at the right age where they've met all of their developmental milestones of gaining weight over the last three months when cubs are first born, they only weigh 3 to 4 pound. they're already weighing in at about 30 pounds. as soon as the habitat was made available for them, they were a little hesitant at first, but soon followed mom shortly thereafter and began exploring their expansive habitat. there are so many choices and habitat features for them to

figure out, to climb, to explore and roll around in too they've been having some fun playing also. >> it's fun certainly watching new animals at the zoo, but it's also fun to watch the reactions of visitors. what have you seen from people as they view the cubs? >> it's been amazing to see the connections between people old and young, small we have these incredible nose-to-nose viewing windows into their habitat so you can get right up and close to the lions here >> they look so cuddly like they could sit in your lap. the reality is obviously they're going to grow big. how big will they get? >> our adult male zabari weighs over 450 pounds. our adult female zari, who's the mom of the three cubs, she's about 350 pounds their growth rate is amazing the cubs' older brother just turned 1 this year

he's already over 230 pounds that growth rate is pretty high. these are wild animals and we respect that. >> when we started, you mentioned pride. cubs that live in the wild they usually live with their mom and dad and other lions and it's called a pride can you explain a little bit more about that structure? >> yeah. african lions live in prides it's a unique family and social coalition. the adult females are very well bonded actually, they kind of rule the roost in terms of managing the adult males. you know, a female when she becomes pregnant will actual ly be at a slight distance from the pride and the cubs won't emerge until they've gotten big enough to explore that's about 3 months old. that's exactly what you're seeing here. >> i understand for kids and grownups not able to visit the

zoo in person, they can view habitats like this from their home. >> we've got web cams running and live streaming our lion habitat, our iguana habitat, our snow monkeys, among others. >> maureen, we really appreciate you talking about this and helping us understand these cubs i spent a lot of years living in chicago just few blocks from lincoln park zoo thanks for what you guys continue to do and to educate us about these animals. great to have you on the program. >> thank you so much we miss you too, lester. >> take care. well, it was a golden moment in massachusetts recently as one group of four-legged friends came together to honor one of their own.% aa erin mclaughlin has more. >> reporter: they're lovable, affectionate and so doggone

cute golden retrievers, a popular breed, especially among this group. >> there's something about the breed. they're so pure, genuine and loving they're just the best friends. they have energy, yes, but they can also be your best friend and lay on the coach all day it's amazing how you can go from being in a bad mood to laughing. she cracks me up all day long. >> reporter: today a golden moment took place. about 200 golden retrievers and their owners gathered by the finish line of the boston marathon to pay tribute to one of their own, spencer, the boston marathon dog who sadly passed away earlier this year. >> it's powerful. >> reporter: the massachusetts golden meet-ups group decided to

do a special walk in his honor. >> that means getting together with the golden community and supporting spencer. >> reporter: spencer became the official race dog after video of him holding boston strong flags went viral several years ago on sunday many participants were wearing bandannas with the slogan "golden strong". >> everyone can use a smile. who better to bring a smile? >> reporter: smiles are contagious when you're around these pups. >> hopefully our dog will be the next spencer and cheer people on. >> this is milli she's a silly little girl. >> this is cruiser and bentley they work here with me >> this is rocket. he's from the police department. >> reporter: cruiser, rocket and rebel also took place in the walk. >> it's a specially trained dog

that can interact with students and families and members of the community and help during crisises more popular than i could have ever thought. >> this is bodhi and he's 2 1/2. i'm training him to be a therapy dog. >> reporter: there's a special connection among the golden community. >> there's something special about people who are drawn to golden retrievers. >> it's such a tight knit community. we feel like everyone's goldens are ours. >> they are a totally different mold they are so pure at heart, so loving they bring people together i swear there's a certain type of person that is drawn to golden retrievers. >> this is patty and he loves the microphone. >> reporter: a special breed bringing people together and spreading joy wherever they go >> golden strong >> erin, that was great.

finally in our inspiring kids series, a fourth grade class is turning a history lesson into action, trying to bring an important piece of american history back home to utah it's small enough to hold in your hand, but at one time connected a continent together this small golden spike was part of one of the greatest achievements of the 19th century. now one fourth grade class in utah wants to bring it home. >> the spikes are really important. the history behind them is really important too >> reporter: to understand the history, you need to go back, way back to the 1800s to a place called promotory point, utah jersey explained. >> i'm jersey. in 1869 the final track of the

trans continental railroad was lalaid peopople canan now travel acrose country in a few days instead of weeks or months. >> reporter: four spikes were used in a ceremony on may 10th, 1869, when the railroad was completed in utah. it was a big deal. >> it's a very important part of utah history it helped make utah the cross roads of the west. >> reporter: the golden spike was the last one used to join the rails of the trans continental railroad connecting the east and west coasts years later, this important piece of american history would wind up in another state. >> to them in california it's no big deal to us in utah, it's really big. >> reporter: the golden spike is housed in this case at stanford university's cantor arts center in california. why california well, the golden spike was privately owned by leland stanford

he founded the university that bears his name. >> at stanford university they might not know what the spike is when they see it there is no explanation of what they're looking at or anything explaining its history. >> that really puzzled me. to us, it's a huge deal. it's a big part of utah history. we learn about it in fourth grade. >> reporter: the teacher mr. pendleton went to see the spike there california >> didn't really seek that important to them. in that moment i had the idea well i could make this a writing assignment for my class. >> reporter: what started as a class assignment quickly turned into a full-on crusade. >> today we are kicking off a statewide letter writing campaign >> this will probably be the toughest assignment i've ever done, because i've never done anything bigger than this. >> spikes to utah! >> reporter: spikes to ut iah ws

formed the students know getting this artifact back to utah is no small feat but with the anniversary approaching, the students are hoping to encourage kids and grownups across the country to send in letters of support. >> regardless of the outcome, this is something that hopefully they'll remember for the rest of their lives. the idea of engaging in civic discourse and learning how to be an activist for things that you care about is important. >> together we can bring the spikes to utah. >> spikes to utah! spikes to utah >> well, that's going to do it for us parents, just a reminder, if your child has a question about any topic in the news, e-mail a video to us at nightlynewskids at nbc uni dotcom. catch a new episode of "nightly news" kids edition every thursday on nbc news dotcom and youtube and streaming on the weekends on nbc news now

thanks for watching. remember to take care of yourself and each other. have a great weekend - life is uncertain. everyday pressures can feel overwhelming

it's okay to feel stressed, anxious, worried, or frustrated. it's normal. with calhope's free and secure mental health resources, it's easy to get the help you and your loved ones need when you need it the most. call our warm line at (833) 317-4673 or live chat at calhope.org today.

♪ good morning. it is saturday, april 22nd. we are taking a live look outside. the sun is shining on san francisco as we lo f