The Life of the Wood Frog: A Chronological Order Text

    One hot summer day, my son and I discovered a tiny frog on the trail at a state park. We were in the forest, far from a creek or pond, and the little frog hopped along unconcernedly, peering back at us through its black mask. At home, I looked up the tiny amphibian and was delighted to learn that I had encountered a wood frog!

     Over the next few years I started looking for wood frog eggs and tadpoles in vernal pools. We even tried raising some in the classroom! When I was looking for topics for chronological order texts, I decided to research the life cycle of the wood frog. These little frogs have fascinated students in my class for many years.

    I enjoy teaching with this text so much that I have made it available in multiple formats. For a digital activity, click here: Informational Text: The Life of the Wood Frog.

    You can also find this activity in a printable format, with other chronological order texts, here: Close Reading with Chronological Order Texts.

Reading level: 4/5, lexile 970

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The Life of the Wood Frog

  Winter Nights

 Think about spending the night in the forest on the coldest night of the winter. To survive, you would need to wear a heavy coat, boots, a hat, and gloves. Even with all of these items, it would still be a very cold, very long night.

 In the forest, you might be sitting within a few inches of a tiny forest survivor. The wood frog lives through winter without a coat, without a hat, even without being warm-blooded. More amazingly, wood frogs have been found to freeze solid in winter. A night that would be dismal for you would be no big deal to a frozen frog-sicle.

Although they are small, wood frogs are interesting. From their birth in vernal pools to their secretive lives in upland forests, wood frogs have been surprising scientists for over a hundred years.

 Springtime Awakenings

As the winter days grow longer and the temperature warms, the frozen wood frogs thaw out and awaken. Depending on the daily temperatures, this can happen in late February to early March. The wood frogs then head off to a special place called a vernal pool. A vernal pool is a forest pond that is only wet in the springtime. Because of this, no fish live in vernal pools.

   Male and female wood frogs gather at vernal pools. Male wood frogs chorus at night, making sounds that have been compared to the quacking of a duck. Their chorus can be quite loud, often blending in with the sounds of spring peepers and other springtime frogs. 

Shortly after mating, the female frogs lay eggs. They often create large masses of eggs, attached to a stick or some other vegetation. These large egg masses are called “rafts”. Putting many eggs close together may help keep the eggs warm. After only one or two short weeks at the vernal pool, the adult frogs leave to return to their solitary lives in the forest.

Growing up in a vernal pool

 The wood frog eggs are left behind in the vernal pool. With no fish around, the eggs have few predators. But there is a risk to this strategy. The wood frog eggs need to develop into tadpoles quickly, before the pool dries up at the end of the summer.

 Wood frog tadpoles emerge from their eggs in April. They are tiny, black, and hungry. In the vernal pool, they find plenty of food to eat—decaying leaves, algae, and other plant matter. As they eat and grow, the tadpoles change color, becoming more of a greenish-brown.

The tadpoles eat their way through the rest of the spring. Scientists have found that they are able to recognize their “siblings”, other tadpoles from the same wood frog parents. These siblings often group themselves together in the vernal pool. Scientists think that sticking together helps them to find food and avoid predators.

As May turns to June, the tadpoles start to grow legs. First, the back legs grow. Then, the front legs develop. Tadpoles stop eating shortly before they finish their transformation. Finally, their lungs develop and they are ready for life on land.

Warm weather can speed up the transformation process. As temperatures warm up, the tadpoles may develop more quickly. Tadpoles that have not developed when the vernal pool dries up may die or be eaten by birds or small mammals. For this reason, the faster transformation may help wood frogs to survive.

 Return to the forest

 After they have fully developed, the baby wood frogs leave the vernal pool. Unlike other frogs, wood frogs prefer dry, upland forests, and do not live near water as adults. Once the wood frogs leave the pond, they lead somewhat mysterious lives. If you go into the forest to find wood frogs, you may be disappointed. There is no one place where you can dependably find the small amphibians. But a small wood frog might jump across your path when you least expect it.

Wood frogs eat insects and other small invertebrates throughout the summer. When the air turns cold in November or December, they shelter under leaves or logs. Special substances in their blood actually promote freezing. By controlling the freezing process, wood frogs can prevent jagged ice crystals from tearing apart their cells. Instead, the ice forms in the spaces between cells. This allows the wood frog to survive being frozen.

This amazing ability of wood frogs was very surprising to scientists. The first accounts of frozen wood frogs, written in the early 1900s, were viewed with disbelief. In recent years, scientists have become very interested in this ability of wood frogs. Many biologists have investigated wood frogs too see if their freezing tolerance could be useful to humans, especially for medical procedures such as organ transplants.

Throughout the rest of the winter, even on those frozen nights when you would huddle indoors, wood frogs stay frozen in their winter shelters. In February and March, as the days grow longer and the temperatures increase, wood frogs awaken. Once more they make their journeys to the vernal pools.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

Mole Crabs: Life at the Water's Edge

      When my children were little, looking for tiny mole crabs became a summer tradition. These little crustaceans spend their lives in the crashing waves. I knew I had to write an article for students about these charismatic crabs!

      This article is written in a statement and support text structure. You can find the formatted version, plus activities and a companion story, in this text set: Comparing Texts.

Grade level: 3/4, lexile 760

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     Imagine living in a place where the salty ocean water crashes against you. Where every wave pounds against the sand, a place of noise and crashing water. To the tiny mole crab, this is home sweet home.

If you have ever visited a beach, you have probably seen one of these creatures. Mole crabs are one of the few creatures to live in the area of the beach called the surf zone, where the water meets the sand. Like other crabs, mole crabs have ten legs. If you have ever held one, you probably know that they love to dig! 

This digging is what helps them to survive in the surf zone. Mole crabs always dig backwards into the sand. As waves crash over them, they stick out their antennae. Bits of food are always churning about in the ocean water. These food bits stick to their antennae. Then the mole crabs can eat the food!

Digging also helps mole crabs to escape from predators. Sea gulls find them pretty tasty. Larger crabs, like ghost crabs, will also eat them. And people often collect mole crabs to use as bait for fishing. 

But mole crabs are more than just prey. They are fascinating little creatures, tiny crabs that live in a harsh place. Mole crabs can be found in many different areas, and have many different names. In some places, they are called sand crabs. They are also called beach hoppers. 

The next time you find one, observe it carefully. Can you find its antennae? How many legs does it have? Can you see it digging backwards? These little creatures have a lot to share! 

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

The Peregrine Falcon: Description Text

 From our visits to zoos and nature centers, my own children were always fascinated by peregrine falcons. And why shouldn't they be? Peregrine falcons are amazing creatures, with speed, power, and an amazing survival story.

I featured peregrine falcons in a text set for "Introduction to Text Structure," a multi-level unit aimed at third and fourth grade readers. You can find the formatted text, as well as activities and lesson plans, in this unit. 

Reading level: Third and fourth grade, lexile 520

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 What is the fastest animal on Earth?

Many people would say the cheetah. It’s true that cheetahs are very fast. 

But the fastest animals on Earth don’t run on land. They fly in the air. Peregrine falcons are the fastest!

  Peregrine falcons live all over the world. They all look similar. Peregrines are 1-2 feet tall. They have a wingspan of up to four feet. They have a sharp, hooked beak. Their wings are dark gray to black. They have fine stripes of brown, gray, and white across their chests.

But the most important features of peregrine falcons help them to go fast. Peregrine falcons eat birds. They dive to catch these birds in the air. When they are diving, they can reach speeds of over 200 miles per hour. That is as fast as a race car! Their long wings help them to make their fast dives. Special nostrils help them take in air as they dive. And they have a sleek, streamlined shape. 

Peregrine falcons are the fastest animals in the world. They are amazing to see—unless, of course, you are a small bird.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

Skunk Cabbage: A Stinky Sign of Spring

 A description text about the skunk cabbage, a delightfully smelly sign of spring!

When I started tracking phenology about ten years ago, some of my students didn't know what skunk cabbage was. This isn't surprising--it's not a plant that most people choose to have in their yards! However, skunk cabbage is an important wetland plant of the Northeast, and the flowers are a very special early sign of spring. I wrote this text to teach students about skunk cabbage. My efforts were rewarded, as the weekend after I taught using the text, a student came back and told me that she and her mom had found blooming skunk cabbage in a nearby park!

To get the formatted article and activities, click here: Description Texts for Teaching Text Structure

Reading level: Fifth grade, lexile 860

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 A Stinky Sign of Spring

Picture spring flowers. You probably imagine yellow daffodils, red tulips, and purple violets. Now breathe deeply. Ah, the sweet smell of—skunk?

 It’s true. One of the earliest spring flowers has a strong smell that some people say is just like the scent of a skunk. Not surprisingly, this flower has the name of skunk cabbage. 

First Flower

 In many parts of North America, the skunk cabbage is the first flower of spring. This first flower is pretty amazing. Due to a chemical reaction, the skunk cabbage can melt the snow around it. The temperature around a skunk cabbage flower might be as much as 30 degrees warmer than the surrounding air.

The flower of a skunk cabbage is also unusual. Instead of having a center and petals, it is made up of two parts. A modified leaf called a spathe wraps around the flower like a hood. This makes a warm little “room” for the flower head, called a spadix. The yellow flower head is packed with small yellow  flowers.

Why does the flower have such a strong smell? Flowers have scents to attract insect pollinators. The skunk cabbage is no exception. The flower’s odor attracts the season’s first insects, like gnats, bees, and flies. These insects pollinate the flowers so that the skunk cabbage can make seeds.

Wet Woodlands

This plant likes places that are wet and shady. Skunk cabbage is often found near streams and vernal pools. The roots of the skunk cabbage have an amazing ability to burrow deep into the moist mud. As they grow, the roots pull the plant deeper and deeper. Older plants have such long roots that it’s almost impossible to dig them up. 

 

Lush Leaves

 The red and yellow flowers of the skunk cabbage don’t last long. After about two weeks, they shrivel up. At about the same time, the leaves of the skunk cabbage start to poke through the wet soil.  The lush green leaves are beautiful to look at, but be careful—they have the same strong smell as the skunk cabbage flower.

Seeing a skunk cabbage flower is one of the most magical moments of early spring. Even though it has a smelly name and doesn’t look like everyone’s ideal spring flower, the skunk cabbage is a welcome sign of spring.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

The Biotic Index: Learning about Water Quality

 Planning a field trip to a stream? Get kids ready by teaching them about the biotic index! This reading selection for fifth and sixth grade students is organized in problem and solution text structure. Students will learn how the biotic index solves the problem of tracking water quality over time.

As I prepared students for field trips to a stream, I knew that I needed a simple reading selection to explain the biotic index. Unfortunately, I had trouble finding one! At the same time, I was working on selections for a problem and solution text structure activity. I realized that the story of the biotic index is a great topic for problem and solution--and if students are going on a stream study field trip, it is a topic that they can live and experience.

You can get a formatted version of this text along with student-ready activities here: Problem and Solution Texts for Teaching Text Structure.

Reading level: Fifth grade, lexile 860

For more advice on leading stream studies, check out this blog post: Leading Stream Studies for Kids.

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Looking for Pollution: The Biotic Index

Does this stream look polluted?

It’s important to know if a stream is polluted. When scientists know that a waterway has poor water quality, they can try to find the source of the pollution.  Many scientists work to keep track of
pollution levels in creeks, streams, and rivers.

  But it’s not always easy to find pollution. Some pollutants, like sewage, dirt, and certain chemicals, are easy to see. But other pollutants, like nitrogen and phosphorus, are less obvious. Making the matter even more difficult is the fact that pollution might not be visible every day. A chemical pollutant might be present in a stream one day, but absent the next.

Using chemical tests to find pollution can become expensive. Different pollutants are found with different tests. To get a good picture of the overall water quality, a scientist would need many test kits. Luckily, scientists have developed an easy and inexpensive way to see if a stream has good water quality—the biotic index. 

Pollution Tolerant or Pollution Sensitive?

 “Biotic” refers to living things. So the biotic index is a survey of living things in the waterway. While all creatures are affected by pollution, some are more sensitive than others. By looking at which creatures are in a creek, a scientist can make a good guess about the water quality of the creek.

 The creatures on the biotic index share some common traits. They are all invertebrates, which means that they don’t have a backbone. They all have short life spans, usually under a year. They are all large enough to see without a magnifying glass. While some of them might be familiar, like crayfish, others are less well known, like caddisfly larva and isopods.

But the creatures have many differences. Stonefly larva, mayfly larva, and crayfish are all sensitive to pollution. This means that they would probably not be found in polluted water. On the other hand, leeches and gilled snails can tolerate pollution. These creatures may be found in polluted water. Of course, just finding a leech does not mean that a waterway is polluted. To carry out a full biotic index, a volunteer counts how many different kinds of creatures are found, and in what numbers.

A biotic index is easy to use. In fact, people who are not scientists can quickly learn how to identify stream creatures and record data. And this is good news, because, with miles and miles of streams and creeks, many volunteers are needed to keep tabs on water quality.

Look at the stream picture again. Suppose that you found three mayfly nymphs, two crayfish, and five stonefly larva in the water. What guess might you make about the water quality?

 Keeping waterways healthy is an important task. With the help of the biotic index, everyone has an easy way to find out the quality of the water in a creek.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

Mysterious Milk Sickness: A Cause and Effect Text

Teach about cause and effect and American history with one quick text! 

A few years ago I purchased a plant that was labeled as "chocolate Joe Pye weed." When I looked up the botanical name of the plant, I was surprised to learn that it is commonly known as white snakeroot--and that this plant played a significant role in America's past. I knew that I had to write about it! Researching the long journey to the eventual consensus on the cause of milk sickness had me deep in the depths of historical texts and medical journals.

This text was written for my Cause and Effect texts packet, and it shows a common pattern of texts written to show the search for a cause. Like many cause and effect texts, it also has a heavy element of chronological order. I also wanted it to clearly communicate the difficulties of medical treatment in pioneer times and the hardships faced by settlers.

To find a formatted and student-friendly version of this text with reading activities, click here.

Reading level: Fifth grade, lexile 810

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Mysterious Milk Sickness

Settlers who traveled to Ohio, Illinois, and Kentucky in the early 1800s faced many hardships. They left behind homes and farms to live in the wilderness. They cleared land and planted crops, working long, hard hours. They often lived in tiny settlements far from towns and stores.

One of the most tragic hardships that settlers faced was a mysterious illness called “milk sickness.” This illness killed many people, especially young children. When people became ill, they often trembled, threw up, or had terrible stomach pains. There were no medicines that seemed to help.

 Milk Sickness and White Snakeroot

People in the 1800s took their cows with them when they went to settle new areas. After all, they liked milk and butter just as much as we do today. Many people know that cows eat grass. But cows will eat other plants as well. When the weather is dry, and the grass gets brown and withered, the cows will look for other food.

 This is what caused the trouble with milk sickness. A tall plant with white flowers grows all through the Appalachian Mountains and the Midwest. This plant is called white snakeroot. Most settlers hardly noticed the plant at all. 

But their cows did. In settled areas, where cows were fenced in, milk sickness was not a problem. On the frontier, however, cows were often allowed to wander far and wide. When the weather was dry, cows often ate the white snakeroot that grew in the forests. 

White snakeroot contains a toxin, or poisonous substance, called tremetol. This substance was not deadly to the cows. However, the poison got into their milk. When people drank the milk, they became ill. Many died.

The Search for a Solution

Strange as it may seem, people did not connect white snakeroot with the milk sickness for a long time. Most medical research was happening in the East, far from the milk sickness outbreaks. People thought that milk sickness was caused by everything from poison dew to poison ivy to even witches. In some places, people realized that milk sickness was worse in dry summers. Some people even noticed that milk sickness vanished when cows were kept in fenced-in fields. 

There are some stories about a woman doctor, Anna Pierce Hobbs, who may have solved the mystery of milk sickness as early as the 1830s. “Dr. Anna,” as she was called in rural Illinois, supposedly learned about white snakeroot from a Shawnee woman. As the story goes, she got rid of white snakeroot in her county and ended outbreaks of milk sickness.

It’s hard to find out if this story is true. It’s possible that white snakeroot was recognized as the cause of milk sickness in some places. But proving that white snakeroot caused milk sickness was difficult. White snakeroot in the eastern part of the United States is less poisonous than white snakeroot in other areas. One doctor ate some white snakeroot to prove that it wasn’t the cause of milk sickness. He was fine—probably because he ate the less toxic form of the plant. 

Scientists also worked differently in the past. They sometimes tried to prove that their ideas were correct. For example, one doctor fed white snakeroot to several rabbits. Even though some of the rabbits died, the doctor wrote a paper to say that white snakeroot did not cause milk sickness. Many doctors continued to believe that poison ivy caused milk sickness.

By the early 1900s, many doctors were beginning to suspect white snakeroot as the culprit. In 1928, Dr. James Couch discovered the exact toxin in white snakeroot. This substance, tremetol, reacts in the body to become a poison. The American Medical Association officially announced white snakeroot as the cause of milk sickness. A mystery that had spanned two centuries was finally solved.

 

Milk Sickness Today

Could someone get milk sickness today? It’s possible, but not very likely. Dairy farms have to follow strict rules. In addition, a glass of milk that you drink today would probably contain milk from several different cows. Even if one cow did eat some white snakeroot, a glass of milk would not contain enough to be toxic. 

 For towns across the Midwest and Appalachian Mountains, milk sickness had a tragic impact. Many people, including Abraham Lincoln’s mother, died of the disease. In some settlements, half of the settlers were lost. Milk sickness made pioneer life even more sad and difficult.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.

How do thunderstorms form? A Chronological Order Text

Address science standards and chronological order with one quick text. 

When my kids were growing up, they constantly asked, "Why?" These questions were especially common in the summer, when we drove far and wide to explore Pennsylvania's state parks. I had to keep a step ahead of them to explain the phenomena they saw around them: mountains, rivers, waterfalls, and storms. So when I sat down to write a chronological order text about a scientific process, I reached back to our long car trips to write about the development of a thunderstorm.

Reading level: Fifth grade, lexile 750

For student ready activities and formatting, click here.

Thunderstorms

Imagine swimming on a hot, sunny day. Only a few puffy clouds dot the sky. As the afternoon goes on, those bright, billowing clouds turn dark and threatening. A distant streak of lightning causes a rumble of thunder. Before there is time for one last game of ‘Marco Polo’, the lifeguard blows the whistle and calls everyone out of the pool. Another swimming day ruined by a summer thunderstorm.

Hot Air Rises

It might seem as if thunderstorms exist only to ruin summer fun. But there is a scientific explanation for these swiftly forming storms. Have you ever seen a hot air balloon? If so, you have seen that hot air rises. 

  This is what happens on summer days. Warm, moist air rises into the atmosphere. In some situations, this air quickly cools, and no thunderstorm forms. But on certain days, the rising air is relatively warmer than the air surrounding it. It continues to rise. A thunderstorm begins to form.

 As the warm air rises, it begins to cool. The moisture begins to condense, or turn from a gas to a liquid. This forms a cloud. The cloud grows as more warm air rises and moisture condenses. Columns of warm air are called updrafts. The water and ice droplets inside the cloud build up an electrical charge. Eventually, lightning can be seen.

Ice droplets from high in the cloud melt as they fall, turning into rain. When this falling rain causes downdrafts, the thunderstorm is fully formed, or mature. Lightning flashes and thunder booms. Often, thunderstorms don’t last long. A short storm quickly rains itself out and dissipates, or falls apart. The storm may vanish within half an hour. These short storms are called single-cell thunderstorms.

Multi-cells and Supercells: No swimming for you!

  After a single-cell thunderstorm, the sun may come out. Everyone can get back into the pool. Summer fun is on the schedule!

But, as you have probably experienced, some storms last much longer than 30 minutes. Longer storms can happen in several ways. In some cases, thunderstorms form in clusters. These clusters can become a line of storms called a squall line. Each individual storm is fairly short-lived, but the line of them can last for hours. As long as thunder is rumbling, no one will be allowed back in the pool!

The most serious kind of thunderstorm is called a supercell. These storms occur when there is wind shear, changes in wind speed and direction, in the atmosphere. Supercells have strong updrafts and can be up to 15 miles wide. In many cases, supercells cause severe weather, including hail, flash floods, and tornadoes. When a supercell is nearby, swimming should be the last thing on your mind. Instead, work on finding a safe shelter from the storm. 

Thunderstorms around the world

Whether they are single-cell, multi-cell, or supercell, thunderstorms are very common. As you read this sentence, there are probably about 2,000 storms going on around the world! In one year, there are more than 15 billion thunderstorms. But only ten percent of these are usually severe.

Thunderstorms do serve a purpose. They help to release energy from the atmosphere. In addition, thunderstorms balance out the electrical charges between the Earth and the atmosphere. No one really knows what would happen if there were no thunderstorms.

In the United States, the National Weather Service (NWS) monitors weather conditions. If conditions are right for a severe thunderstorm, meteorologists issue a severe thunderstorm watch. This tells people to be on alert. If a severe storm is headed your way, meteorologists issue a severe thunderstorm warning. This means that you should seek shelter.

The next time that you see darkening clouds on the horizon, don’t be upset. Even though you might lose out on some summer swimming time, you might get to see one of Earth’s most exciting events—a thunderstorm.

by Emily Kissner

©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale