Free Earth Science Unit Study Part 3 - Biomes

This is an eight week biome unit study perfect for kids in 3rd-5th grades. This unit study covers deserts, rain forests, grasslands, chaparral, tundras, soil, and water biomes. The lessons are activity intensive but also incorporate books, video documentaries, research and discussions opportunities.

Week 1 - Biomes
Week 2 - Rain Forests - Hygrometer
Week 3 - Deserts
Week 4 - Sand Storms
Week 5 - Desert Oasis - Water Beneath the Surface
Week 6 - Grasslands - Soil Drainage
Week 7 - Soil Acidity
Week 8 - Water Biomes

Week 1: Biomes

Plants and animals each have their own preferred climate. Some like the damp heat found in tropical rain forests, while others prefer the dry heat found in deserts. Watch the video Biomes of Our Earth: Major Life Zones which describes characteristics of the major biomes and explains how latitude effects land.

 Biomes of Our Earth: Major Life Zones

Going up in elevation is much like going north in latitude when it comes to biomes. Tropical rain forests are typically found near the equator (0 latitude) and near sea level in elevation, where as tundras, a cold treeless area of land, is typically found high on mountain tops and above the arctic circle. The other biomes such as chaparral and temperate rain forests are found at mid latitudes and mid elevations.

Read these picture books set in different biomes.

North Pole South Pole
The Magic School Bus: All Dried Up: A Book About Deserts
In the Rain Forest: A Book about Rain Forest Ecology (Magic School Bus)

How does ground cover affect the temperature of the environment? Do the experiment in chapter 25 of Janice VanCleave's A+ Projects in Earth Science.

  • Shoe boxes
  • Ground materials such as sand, rocks, mud, grass, leaves
  • Thermometers
Fill three shoe boxes with different ground materials such as sand, soil and grass.

Place the boxes in the sun and put thermometers on top of the ground materials. Read the thermometers every 15 minutes over the course of an hour. Which box was the hottest?

Discuss any visits you have taken to biomes different from the one you live in. Have you ever been at a beach that contains grass and sand? When stepping onto the sand from the grass, feet can sometimes burn with the heat. Sand covers the desert. Did you have a box with sand? Was it the hottest one?

Week 2: Tropical Rain Forest

Tropical rain forests are the most inhabited places on the planet. Plants thrive in hot, humid and wet environments and provide an abundance of food for animals. Watch David Attenborough's Living Planet - Jungle which provides glimpses of many unique plants and animals of the rain forest including a native tribe who have learned to live in the unusual environment. If you can't find that video, watch another video on rain forest life.

Rain Forest Books 
Read Welcome to the Green House by Jane Yolen. It is a picture book of the rain forest good for young children.

Read Rainforest Babies. Each page details a different rain forest animal with interesting information such as frogs so poisonous they can kill an entire village. Did you know chameleons aren't born knowing how to change color? They learn it like we learn to walk, and they communicate through color.

Read In the Rain Forest: A Book about Rain Forest Ecology (Magic School Bus) As the Magic School Bus kids journey through the rain forest they learn where chocolate comes from and see many plants and animals.

Rain Forest Maps
Print a world map and label the rain forests. Notice that most rain forests are located near the equator.

Rain is an essential component of the rain forest, and humidity measures the amount of water in the air. Hygrometers are a device that measure humidity. Construct two hygrometers using two short pencils, two glass jars, two empty spools of thread, newspaper, aluminum foil, and tape as described in the book Janice VanCleave's A+ Projects in Earth Science: Winning Experiments for Science Fairs and Extra Credit.

Cut a strip of newspaper and tape it to a slightly larger strip of aluminum foil. Then coil the newspaper and aluminum foil around one of the pencils. Stick the pencil into the spool and place in one jar.

Repeat the steps the second jar.

Simulate a dry environment for one hygrometer and a humid environment for the other by drying one jar out with a hair dryer, and placing a bit of warm water into the other.

Put the lids onto the jars and let the hygrometers adjust. Notice that the one in the humid environment is coiled looser than the one in the dry environment. As the newspaper absorbs water, the paper pushes against the foil causing it to unwind.

Create another hygrometer using a strand of hair. As humidity in the air changes, the length of hair strands change.

Attach a strand of hair to one thumb tack, and punch a hole in a piece of triangular paper which will be used as an indicator. Next stretch the hair tight and tack down the indicator to the cardboard so that it can rotate as its length changes. Mark a line to show the initial position of the indicator. Check the indicator daily and notice how it moves with respect to humidity.

Week 3: Desert and Rain

Watch How the Earth was Made - Sahara which is available on the History Vault. A low cost streaming service operated by the History Channel. In the video scientists search for clues to unlock the secrets of the Sahara desert. Scientists believe that since the Earth rotates on its access, every 20,000 years, there are major shifts in the locations of the Earth's deserts. Nummulite, tiny ancient sea creatures, were found in the blocks used to construct the pyramids. Bones of extinct whales have been found throughout the desert. Both of these clues indicate the desert was once a great sea.

Watch the video the Baking Deserts, where scientist also point to the evidence proving that the desert was once a sea. Cypress trees estimated to be 3000 years old still live today in the desert. Cave art showing antelope, giraffe and cattle has been found in the Sahara.

David Attenborough describes how several desert plants and animals have adapted to survive in the harsh environment. Animals such as rabbits and foxes have extra long ears which act as cooling fins. Birds learn to breath in a special way which helps them keep cool. Squirrels use their tails as umbrellas to shield them from the sun. Some plants coat their leaves with salt to reflect heat. Others, such as American cactus, have turned their leaves into thorns and use the stem for photosynthesis. 

Since rain is scarce in the desert, complete two hands-on projects centered on rain from the book Janice VanCleave's A+ Projects in Earth Science: Winning Experiments for Science Fairs and Extra Credit. In the first project, determine the diameter of different types of rain. In the second project form rain droplets around crystals of salt.

Thundershowers, mist, and drizzle all describe different types of rain, and each type has unique characteristics. One trait scientists use to distinguish between types of rain is the diameter of the droplets.

Begin by sifting flour into a pan and using a spray bottle to simulate rain.

Next scoop the rain drops out of the flour and sifted again to collect them.

View the rain droplets on a dark background through a magnifying glass and measure their diameters.

Place the pan in the rain so actual rain drops can be collected. Measure and compare with the spray bottle drops.

High in the atmosphere, rain drops form by condensing onto specks of dust. To simulate this process, place a few grains of salt in a humid environment and observe to see if drops of water condense onto them.

Cut a dark sheet of construction paper to fit inside a lid of an old container. The dark color makes it easier to view the salt.

Next, smear the paper with petroleum jelly to prevent water absorbing into the paper and place a few grains of salt on top of the paper.

Place a small amount of water in the pan and float the lid on the water. Cover the lid with a slightly larger container.

Check the size of the water droplets after a few hours and the next day. What happens to the water droplets?

Week 4: Desert Sand Storm

Sand can fly in dry deserts. In fact, some sand from the Sahara desert in Africa travels with the jet stream and lands in the Amazon rain forest of South America providing vital nutrients for the plants. Watch the video How The Earth Was Made - Sahara Desert available at the History Vault.

Follow the desert sand experiment detailed in How the Earth Works (How It Works).

Place a small pile of sand on some wooden blocks adjacent to an ice cube tray.

Use a hair dryer to create a sand storm.

Examine the ice cube tray to determine which grains traveled the farthest. Do smaller grains or larger grains travel farther? Discuss the similarity of sandstorms and erosion.

Sand blown into the air can be carried hundreds of miles by the wind and it's the smallest grains that travel the farthest. Boulders, rocks, and pebbles on mountains can be carried hundreds of miles by water in rivers, and it's the smallest rocks which travel the farthest.

Week 5: Desert Oasis

Beneath the surface water flows down through the soil. In some places there are underground rivers, lakes and streams. Once water reaches the water table, it can even rise through the soil.

Follow the experiment in chapter 22 of Janice VanCleave's A+ Projects in Earth Science: Winning Experiments for Science Fairs and Extra Credit which explores how water percolates down through soil, how capillary action enables water to move up through the soil just above the water table, and how an aquifer or oasis forms even in very dry regions such as a desert.

The Water Table

To see what water does as it seeps into soil simply poured some water into a mixture of sand and gravel.

An impermeable layer is a layer of rock or clay beneath the surface which is so densely packed that water cannot penetrate. For this experiment the impermeable layer is the bottom of the jar.

Once the water reaches the impermeable layer some of it begins to rise back up through tiny air pockets.

Then it finally settles and a water table line is clearly visible. Above the line the spaces between the sand and gravel are filled with air, and below the spaces are filled with water.

Rising Water - Capillary Action

Because there is a molecular attraction between liquids and solids, liquids can defy gravity and rise into small spaces. Seeing colors run up through coffee filter paper dipped in water, water rising into a paintbrush, and surface tension are other examples of this phenomenon.

To see how capillary action is related to Earth science, fill a plastic cup containing holes in the bottom with sand and and placed the cup into a dish of water.

After a few minutes the water can be seen rising above the level in the dish.

A Desert Oasis
It's so strange the way an oasis can pop up in the middle of a dry desert. Water is trapped beneath the surface in many locations throughout the desert. With an impermeable layer both above and below, it cannot get out unless it finds a crack. 
To create an oasis in a bowl, first line a bowl with clay. The clay serves as the impermeable layer under the water.

Next place a permeable layer of sand on top of the clay.

Then add more clay on top of the sand for the upper impermeable layer.

Press all three layers into a bowl shape. Then place a hole  in the clay so that the water has a crack to escape from the impermeable layer. It is important for access to the permeable layer to be left open in order for the water to have a place to enter.

Week 6: Grasslands and Soil Drainage

Grasslands are found all over the Earth, but are known by several different names. The Savannah in Africa, the Stepps of Asia and the Grasslands of North America are all similar habitats. Watch BBC's video Wild Africa which explores several different plants and animals living on the African Savannah as well as the origins of these grasslands.

Much of the food we eat is grown on the grasslands of America, as the soil is rich and the absence of trees facilitates easier planting. One factor which influences the success of growing food is the drainage of the soil. Soil that doesn't drain well is wet and can become very muddy. Conversely, soil that drains too quickly may not hold sufficient moisture required by the plants. Learn about soil grains and water drainage rates by following experiments in Janice VanCleave's A+ Projects in Earth Science: Winning Experiments for Science Fairs and Extra Credit.

Separate soil by sifting with three different sized strainers.

 The double sifting results in fine, medium and coarse grain soil.

Measure the quantities of each sample to determine what size particles are in the soil.

Now determine the drainage rate of the fine grains, coarse grains, rocks and clay.  Place a sample of soil into a yogurt container containing holes poked through the bottom. Make sure the holes are not excessively large. Pour 200 ml of water into the sample. Once the water is added start a timer to measure how long it takes for the water to slow to a drip. Collect the drained water and measure to see how much drained out. Then calculate the drainage rate by dividing the amount of water collected by the time it took to collect.

Week 7: Soil Acidity

Acidity levels in soil are one variable which can lead to a successful or unsuccessful garden. Most plants prefer neutral PH levels around 7. Soil located under pine trees is often acidic and using nitrogen fertilizers can lead to acidic soil issues.

At our previous residence there was a pine tree located very close to a plum tree which never produced any plums. One year the pine tree was chopped down, and the next year the plum tree was loaded. At our current residence there was a similar incident. A garden located near a pine tree produced very little and contained few worms and life. One year the pine tree became a Christmas tree for the local church and the next year the garden thrived. 

Water dyed dark purple, which is produced upon boiling red cabbage in water can be used to determine if a substance is basic or acidic. Bases will turn shades of blue and green, while acids turn pink. Here's a color chart for cabbage water PH.

Before testing the soil, use some of the cabbage water to test milk, dish soap, lemon juice and vinegar. The results should indicate that the milk has a PH around 4, dish soap around 9, and lemon juice and vinegar around 1.

Gather six samples of soil in white or clear containers and add cabbage water to each one.

Determine the acidity of the soil based on the color of the cabbage water after it is added to the soil.

Week 8: Water Biomes

A water biome is an area of water characterized by types of plants and animals which inhabit the area. IS THE WATER - Fresh or salty? Deep or shallow? Still or moving? Warm or cold? These questions related to water are prime factors in determining what type of life can thrive.

There are several short videos available which each focus on a different water biome from Untamed Science - a website with many quality introductory science videos for kids. If you cover science its worth checking out. (Not all the videos below are from Untamed Science.)

Fresh Water 
Streams and Rivers
Wetlands Biome (3 min)

Streams and Rivers (4 min)

Salt Water
Near Shore
Coral Reef
Open Ocean
Deep Sea
Vent Communities
Intertidal Biome (7 min)

Coral Reef Biome (7 min)

The Deep Sea (6 min)

Hydrothermal Vents (6 min)

Take a field trip to explore plants and animals in different water biomes. Visit the same water biome through out the year and notice changes.

Pond Biome

Look for frogs

or tadpoles

Use an empty water bottle the kids were able to get a closer look at what is in the water.

baby frogs

Coastal Biome

 Barnacles stuck to a rock



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