National Estuaries Day: Student Activities & Courses

National Estuaries Day is the last Saturday of September. As such, we will celebrate on the 24th this year. Established in 1988 as part of Coast Weeks, the purpose of the annual event is to promote the importance of estuaries and the need to protect them.

With the many threats to the world’s ecosystems, it is critical to prepare our children to be tomorrow’s environmental stewards. Estuaries are an ideal vehicle with which to introduce students to marine ecology. Whether through recreational experiences, scenic views, or making a living on the water, many are familiar with estuaries. estuariesday

All throughout the country, local organizations including National Estuarine Research Reserves and National Estuary Programs organize special events, like beach clean-ups, hikes, canoe and kayak trips, workshops and more to recognize the special role these places play in our everyday lives. It is a terrific opportunity to learn more about estuaries.

Why are estuaries important?

Estuaries are partially enclosed bodies of water usually found where rivers or streams flow into it and with a free connection to the sea. The mixture of fresh water draining from the land and the salty seawater influxes of the tides create habitats where many unique plant and animal communities have adapted to life in the brackish water.

As a result, estuaries are among of the most productive ecosystems in the world. Many animals rely on estuaries for food, places to breed, and resting areas during long migrations. Human communities also rely on estuaries for food, recreation, jobs, and coastal protection.

How can I get involved?

Celebrate National Estuaries Day by learning about the National Estuarine Research Reserves and many local Friends Groups who organize a variety of activities benefiting the local estuary and reserve.

You’ll find numerous ways to connect with your coastal environments whether you are seeking a kayak adventure, want to forage for fungi, explore a class in seaweed art, or take in a history walk – there is bound to be something that appeals to you

nationalestuariesdayWhy teach about estuaries?

Estuaries offer a wonderfully rich context for science education and cross disciplinary learning. As a result of the dynamic ecosystem, estuaries provide an opportunity for learners to integrate many science fields such as ecology, biology, chemistry, geography, geology, and marine science.

Students of all ages can gather data and develop their math skills through detailed measurements of salinity, temperature, and dissolved oxygen. Students also develop language skills as they do further research and begin to communicate their discoveries with other students and scientists. Since estuaries have also played a significant role in human settlement, exploration and development, students gain new eyes on human history, geography, and culture.

Estuaries Curriculum 

I have put together two curriculum units to introduce middle school students to estuary ecology. Each unit is comprised of hands-on inquiry based lessons. A variety of enrichment projects and living books are also suggested to augment the teaching material provided. In honor of National Estuary Week, for the month of September, each of these units is available for 40% off the regular price. 

ecology

Ecology Explorations provides a great introduction to ecology concepts, introducing students to key vocabulary and field collection techniques. It is one of my favorite units because it provides several opportunities to explore your local ecosystems. This 10-week unit includes 20+ activities and lesson plans fully outlined for you. Sale price is $19.90  $11.90.

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Estuary Ecology

Estuary Ecology is a fourteen lesson unit study that focuses upon estuaries and salt water marshes.  It incorporates a month-long moon observation project as well as a field trip to an estuary or salt marsh. The lessons can be adapted to mangroves or tropical regions.  Sale price is $14.90  $8.90.

buynowgreen

A Look at the Industrious Beaver: Nature’s Engineers {Middle School Unit Study}

North American Beaver (Castor Canadensis) play a critical role in the ecology of our streams. Their dams create pooling of water upstream, which creates wildlife habitat for many dozens of wetland and slow-moving water species that wouldn’t otherwise be in such riparian habitats.

These industrious mammals provide a fascinating topic for middle school science investigations. Here you will find a variety of resources and materials to engage middle schoolers in real science related to nature’s engineers, Castor canadensis.

A Look at the Industrious Beaver: Nature's Engineers (A Middle School Unit Study) @EvaVarga.net

Beaver Anatomy & Physiology

Beavers are the largest rodents in North America, and they spend most of their time in the water. To protect themselves from the cold and wetness they have waterproof reddish brown or blackish brown hair. They have small, round, brown ears, and powerful back legs for swimming. A beaver’s front legs are not as large or as strong as its back legs.

Beaver skulls and teeth are very big. The two front teeth are orange colored, and they can be up to 5 mm wide and between 20 and 25 mm long. These teeth grow throughout the animal’s life, and they are used for cutting wood. Without these teeth beavers could not cut down or eat trees and wood. Beavers also have see-through eye lids, and closable nostrils and ears for swimming underwater.

Beavers also have anal and castor glands, which they use to mark their territory. These glands are located beneath the tail. The beaver utilizes the oily secretion (castoreum) from these scent glands to also waterproof its thick fur.

The beaver has a thick layer of fat under its skin that helps keep it warm underwater. Beavers have long sharp upper and lower incisor teeth that they use to cut into trees and woody vegetation. These teeth grow throughout the beaver’s life. A beaver’s tail is broad, flat, and covered with large black scales.

A Look at the Industrious Beaver: Nature's Engineers (A Middle School Unit Study) @EvaVarga.net

Beaver Ecology & Natural History

Important natural processes, such as energy flows and chemical cycles, result from the interaction of species within a community. Food webs of trophic (trophic – pertaining to nutrition) interactions among species are one example of how multiple soil-plant, plant-plant, plant-animal, and animal-plant relationships link together within a functioning community. Some species can be highly influential in their communities, even if they occur at relatively low population densities. When the presence and actions of this species tend to form the foundation of how other species relate to each other in the community, we often call the influential plant or animal a keystone species.

“Keystone” is a metaphor equated to the stone in the middle of an arch in a building. Removal of the keystone leads to destabilization if not outright collapse of the other elements that “lean on” or depend upon that keystone.

A Look at the Industrious Beaver: Nature's Engineers (A Middle School Unit Study) @EvaVarga.netThe beaver is often cited as an example of a keystone species because through its dam-building behaviors it has major influences on both the vegetation of an area and the water table. In turn, these factors have strong influences on the abundance and quality of habitat for many other plant and animal species within the community. They engineer, or create, habitat that supports greater biodiversity that would otherwise not exist.

No other animal with the exception of man can significantly alter its habitat to suit its own needs and desires. Native Americans revered the beaver and referred to them as “Little People” for this reason.

In one of the first images of its kind, night-vision cameras recently captured photos of native beavers and invasive nutria working together to build a dam across a channel at Smith and Bybee Wetlands Natural Area in Portland, Oregon.

Beaver Unit Study Resources

Act out a short skit to teach others about the natural history of the beaver – its adaptations for its environment as well as the impact humans have had on it throughout history.

Dress up a volunteer as you learn about the structural and behavioral adaptations of beavers.

Explore the website Beavers: Wetlands & Wildlife to learn more about beavers and their impact on the ecology.

Learn about the history of the Fur Trade and Beaver Ecology including numerous Historical Source Documents.

Learn about Beavers and Climate Change Adaptation Strategies – A Report from Wild Earth Guardians.

Download the Beaver Monitoring App and help scientists study how beavers could be used as a tool for stream restoration and mitigating impacts of climate change.

Reach out to your local watershed associations to learn about watershed monitoring and restoration projects that impact beavers. How can you get involved?

Visit and observe an ecosystem created by beavers in your local area (contact Fish & Wildlife for assistance in locating a dam if you are unfamiliar). Keep a journal of your observations.

zoology

You might also be interested in my 10-week inquiry based science unit introducing middle level students to the study of animals: Zoology: Amazing Animals. Lessons include scientific classification, identifying animal tracks, ecology, and animal behavior.

 

Polymers Are Cool: 3 Recipes for Middle School

Chemistry is great for making many useful products. It’s also good for making stuff that’s just fun to play with. One of my favorite chemistry units is on polymers.

A polymer is a large molecule, or macromolecule, composed of many repeated subunits. In other words, they are made up of many, many molecules all strung together to form really long chains.

Polymers Are Cool: 3 Polymer Recipes for Middle School @EvaVarga.netIn Greek, Poly- means “many” and -mer means “part” or “segment”.  Mono means “one”. So, monomers are the individual molecules that can join together to make a long polymer chain.

A single polymer molecule is made out of hundreds of thousands (or even millions!) of monomers. Not all molecules can link up in this way to form polymers, however.

The atoms that make up a polymer chain essentially line up and repeat all along the length of the polymer chain. For example, look at polypropylene:


Polypropylene is made up of just two carbon atoms repeated over and over again. One carbon atom has two hydrogen atoms attached to it, and the other carbon atom has one hydrogen atom and one pendant methyl group (CH3).

In this example, the pendant group hangs from the carbon atom in the chain backbone. As you can see from the example, pendant groups usually repeat along the length of the chain as well.

But enough of the mumbo jumbo. Let’s get to the fun stuff. What is better than reading about chemistry? Doing the labs, of course!  Here are three tried and true recipes for polymers you can use in the classroom.

Polymer Recipes ~ Get Messy!

Basic Polymer Putty

This is a fun and easy polymer to make (and the one featured in the photographs).

Materials

  • Elmer’s white glue
  • Borax (find in the laundry detergent aisle of the store)
  • Water
  • Two bowls
  • Food coloring (just for fun)

Procedure

  1. In one bowl mix 1/2 cup (4 oz) glue and 1/2 cup water. Add food coloring if you want colored slime.
  2. In the other bowl, slowly mix borax into 1 cup of water until the borax will no longer dissolve (this is a saturated solution).
  3. Add the glue mixture to the borax solution, stirring slowly.
  4. The slime will begin to form immediately; stir as much as you can, then dig in and knead it with your hands until it gets less sticky.  Don’t worry about any leftover water in the bowl; just pour it out.

The glue has an ingredient called polyvinyl acetate, which is a liquid polymer. The borax links the polyvinyl acetate molecules to each other, creating one large, flexible polymer. It will get stiffer and more like putty the more you play with it.

Store it in a plastic bag in the fridge, to keep it from growing mold.

polymer recipesA Firmer Polymer

This recipe makes a firmer, dryer slime that will even bounce if it is kneaded enough.

  1. Mix 4 tsp. (20 ml) water with 5 tsp. (25 ml) Elmer’s or other white glue in a small bowl.
  2. Add 1 tsp. (5 ml) talcum powder and stir until thoroughly mixed.
  3. Add 1 or 2 tsp. (5 or 10 ml) saturated borax and water solution. Stir four a few minutes.
  4. Remove the glob from the bowl and stirrer. Knead it for a while and it will become drier.

You will probably need to wipe off some of the excess moisture from your hands with a paper towel from time to time. Don’t be tempted to wipe the glob with a paper towel as it will only stick. You can add a little talcum to the surface if you are having trouble getting it dry enough. Store in a zip lock in the fridge.

plastics lab activityTake a closer look at plastics & polymers

Super Slime

This slime is similar to the one above, but creates a less rubbery and more transparent slime. This is the real gooey deal! (This slime is non-toxic, but still keep these chemicals away from unsupervised children and wash your hands after playing with the slime.)

Materials

  • Polyvinyl Alcohol (PVA)
  • Borax
  • Water
  • Graduated cylinder or measuring cups and spoons
  • Food coloring (just for fun)

Procedure

  1. Make a 4% solution of polyvinyl alcohol: Stir 1.5 teaspoons (approx. 4g) of PVA into 1/2 C (approx 100 ml) of water in a large microwave-safe bowl. Cover the bowl and microwave for 1 minute, then stir. Microwave another 30 seconds and stir. Continue until all the PVA is dissolved. A slight film may have formed on top; you can remove that with a spoon. You can add food coloring if you want colored slime. Allow the solution to cool.
  2. Make a 4% borax solution by stirring a little less than 2 teaspoons (approx. 4g) of Borax into 1/2 cup of water.
  3. Pour the cooled PVA solution into a ziplock bag and add 2 teaspoons (10ml) of the borax solution.
  4. Zip the bag and knead it until the chemicals are mixed into slime. Then scoop it out and play with it.

While water is a liquid made up of individual H2O molecules, polyvinyl alcohol is formed of long chains of connected molecules, making it a liquid polymer. The borax acts as a “cross-linker,” linking the individual PVA chains to each other. The borax molecules form hydrogen bonds with molecules present in the PVA chains. The partial positive charge of hydrogen atoms attracts the partial negative charge of oxygen atoms. Since hydrogen bonds are weak, they can break and reform as you play with the slime or let it ooze on a flat surface.

Your slime will last for a while if you seal it in a plastic bag and keep it in the fridge.

Misconceptions in Chemistry @EvaVarga.net

Learn how to dispel children’s Misconceptions in Chemistry & Physics.

Helpful Hints for Success with Polymers

Gel type glues

Over the past few years several brands of gel type glues have been introduced. Most of these make excellent slimes which are very elastic and have a nice color and consistency. I have personally experimented with Elmer’s School Glue Gel, but there are several similar products available from other manufacturers. Try substituting a gel glue in the Basic Polymer recipe, above.

Slime overly sticky or runny?

If your white glue or gel glue based slime is too sticky or runny, first try kneading it for a while. Working it in your hands will help to mix things up better, as well as remove some of the moisture. If it is still not quite right, mix 1 part borax with 10 parts water. Dunk the slime into this solution, remove and knead.

Precautions

  • Polymers can wreak havoc with plumbing, so don’t throw them down the drain.
  • Always wear a mask when mixing PVA.
  • Use distilled water for all solutions for best results.
  • Keep polymers away from anything they could damage. They can dry into fabric and the dyes can stain surfaces, including wood.
  • Supervise small children when playing with polymers so they do not ingest any.
  • Some people are allergic to Borax powder. Wearing rubber gloves when mixing should help.
  • Polymers using Borax solutions work best if you pour the Borax solution into the other solution, rather than the other way around. Coloring should be added before the Borax.
  • Use metric measurements whenever possible. This will make it simpler to experiment with different concentrations and ratios.

Cool Chemistry

For more hands-on chemistry lessons like this one, check out Cool Chemistry is a ten-week multidisciplinary, hands-on physical science curriculum that incorporates scientific inquiry and a long-term project. Available today!

 

Getting Started with the Sport of Orienteering

One of our favorite outdoor activities involves just a few materials and is both challenging and fun. With a just a compass and a map, a variety of activities and obstacles courses can be designed to accommodate everyone. It is the perfect summer activity and can be easily integrated into your science or history curriculum.

Orienteering is what is called a lifetime sport; there’s something for everyone to enjoy, regardless of age or experience. Most events provide courses for all levels, from beginner to advanced.

This post contains affiliate links.

Getting Started with the Sport of Orienteering @EvaVarga.net

The history of Orienteering begins in the late 19th century in Sweden where it grew from military training in land navigation into a competitive sport for military officers. Eventually civilians caught on to the sport and the first public orienteering competition was held in Norway in 1897.

Orienteering courses can be set in any environment where an appropriate map has been made and a number of variations have been developed over the years. Some of the more intriguing variations include Night Courses, Trivia, and Relay Orienteering.

Orienteering with Kids can be a lot of fun. It is also a great confidence booster as they develop their navigational skills and can find their way through unknown territory.

To introduce kids to this wonderful sport, I have developed a simple introductory compass course activity to introduce the basics of using a compass for upper elementary and middle school students. It has been very popular with our local homeschool community and I am delighted to share it with you.

Introduction to Orienteering @EvaVarga.netIn my eBook, Introduction to Orienteering, I have included detailed instructions on the use of a compass and outlined a simple Compass Course activity to introduce kids to the sport of Orienteering. In addition, I have compiled numerous enrichment activities that incorporate the use of a compass and topographical maps.

With the Introduction to Orienteering unit study, students will develop the navigational skills and experience to feel confidant in participating in larger, community-wide Orienteering events. You can find more information about these opportunities by visiting the Orienteering USA website.

The Compass Course activity is also a part of my Earth Logic: Our Dynamic Earth curriculum, a 10 week hands-on earth science curriculum unit study on the geology of our Earth.

While the compass has not changed dramatically since it was first invented by the Chinese during the Han dynasty, many other navigational tools have been invented. We loved reading about the tools early explorers used to navigate in North Star Geography and have enjoyed using some of these tools ourselves. I have shared a few of our activities in my post, Sailing Ships & Navigation.

STEM Club: Let’s Get Dirty – Soil Horizons & Particle Size

Soil is the part of the ground where plants grow. Soil is a mixture of tiny particles of rock and rotting plant and animal material, with water and air between them. Soils help plants grow in two ways. First, soil holds the plants into place. Second, soil contains nutrients that plants need in order to survive. These nutrients include water, phosphorous, nitrogen, and potassium.

Over the course of the next few weeks, STEM Club will be investigating soil ecology as a part of the Year of Soils. I’ve shared a few of our past endeavors relating to soils here:

Soil Ecology Activities for Middle School

Cycles and Ecosystems {Free Printable}

Soils Support Urban Life: Rain Gardens & Composting

Soils Support Agriculture: Ideas to Integrate Writing

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Today, I share a lesson on soil horizons and particle size.

Soil Horizons

Soil particles vary greatly in size. The largest particles settle to the bottom first. The fine particles settle slowly; some are suspended indefinitely. The amount of open space between the particles has much to do with how easily water moves through the soil. This also determines how much water the soil will hold, which has a major effect on the type of plants that can grow in the soil.

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Things to look for in soil are color, texture, structure, depth, and pH. A general soil profile is made up of a litter layer, A horizon, B horizon and C horizon. A soil sampling device (pictured in the collage above) allows you to gather data on the soil makeup on any site.

Soil Particle Size

Soil scientists classify soil particles into sand, silt, and clay. Scientists use these three components and the calculated percentages on the texture triangle to determine the textural class of the soil at a given site.

A soil’s texture depends on the size of its particles and living things depend on the right texture to thrive in the soil. Every soil type is a mixture of sand (2mm – 0.05mm; feels gritty), silt (0.05 – 0.002mm; feels like flour), clay (Smaller than 0.002; feels sticky when wet), and organic matter. Squeeze some soil between your fingers. Is it crumbly? Sticky?

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Let’s Get Dirty ~ Terrestrial Soils

One of the best activities to engage kids in the study of soil ecology is the sample the soils around your home or school yard. Begin by asking the following questions:

1.  Are there different types of soil near your home?

2.  What texture class is this soil?

3.  What is the particle size make-up of this soil?

The answers generated prior to the investigation are part of your hypothesis. Record your ideas in your science notebook before you begin and give reasons. Why do you suppose the soil in your yard is predominately sand? What experience or prior knowledge do you have to help you make this statement?

Materials

  • 1 Soil probe
  • 1 Metric ruler
  • 1 Quart jar with lid
  • 1 Set index cards for diagrams

Procedure

  1. Use the soil probe to collect soil cores as deep as possible from a predetermined site.
  2. Diagram and measure the depth of each layer or horizon in your sample.
  3. Fill the quart jar at least half and no more than two thirds full.
  4. Fill the rest of the jar with water, seal tightly and shake vigorously for 10 minutes. Let the jar stand for 24 hrs.
  5. The next day, mark the soil layers of each sample on an index card placed behind the bottle. Mark the top of the soil and the points where the layers change. Calculate the percent of sand, silt and clay in your sample. To do this, measure the following marks you made on the card: entire height, sand (bottom) layer, silt (middle) layer, and clay (top) layer. Then take the height of each layer by the total height and multiple by 100. Record the figures on the data sheet.

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net
Analysis of Results

  1. At which site was the soil the most sandy? silty? mostly clay?
  2. Do you think that this is a trend and would be found at other sites? Explain.
  3. What are some factors that may change the results of this experiment? Explain.

Conclusions

  1. Did you achieve your hypothesis? Explain.
  2. What did you learn by doing this exercise?
  3. Do you think the soil will be the same at other sites (park, forest, meadow, near the shore of a lake or river, etc.)? Design an inquiry project to learn more.

STEM Club: Cycles and Ecosystems

Every spring, when the weather is still yet cool, I like to take our STEM Club outdoors for more in-depth, hands-on ecology lessons. This year, to align with the International Year of Soils, we are focusing on soil ecology.

STEM Club: Cycles & Ecosystems w/free printable @EvaVarga.netAs I begin each ecology study, we review the cycles of energy and nutrients. Ecosystems are characterized by different cycles that enable organisms to survive. Plants and animals interact with each other and with their environment through these important ecosystem cycles.

  • Energy Cycle
  • Carbon and Oxygen Cycle
  • Nitrogen Cycle
  • Water Cycle
  • Disturbance Cycle

The Energy Cycle

An ecosystem is a type of community in which all of the plants and animals that live in it either feed off each other or depend upon one another in some way. Just as people interact and depend on each other in our communities. In each ecosystem, there are different feeding levels called trophic levels: primary producers (or plants) that convert energy from the sun through photosynthesis, primary consumers (herbivores), secondary consumers (animals that eat the primary consumers), tertiary consumers (animals that each both primary and secondary consumers), and decomposers that break down dead or dying matter into nutrients that can be used again by producers.

The Carbon and Oxygen Cycle

Another important cycle in an ecosystem is the carbon and oxygen cycle. Each of these elements is needed in order for plants and animals to live. Plants take in carbon dioxide during the process of photosynthesis. They use the carbon from carbon dioxide to make food which provides matter and energy to make new plant cells. During respiration plants take in carbon dioxide, a gas they need to live, and release oxygen. Animals breathe in oxygen, a gas they need to live, and release carbon dioxide. Dead plants and animals release carbon dioxide during the decaying process. The carbon is stored as fossil fuels that include coal, gas, and oil.

The Nitrogen Cycle

Nitrogen is a gas that makes up about 78% of the air we breathe. It is an important part of proteins and other plant and animal matter. Plants and animals cannot use nitrogen directly from the air. The nitrogen must be changed into a form that plant roots can take up and use. Certain bacteria, like lichen, are able to take nitrogen from the air and change it into a form that plants can use. The process of changing nitrogen into a form that plants can use is called nitrogen fixation. The bacteria break down the nitrogen containing tissues of dead plants and animals and change them into nitrates. Plants absorb the nitrates through their roots and release nitrogen gas back into the air.

The Water Cycle

Organisms need water to survive. The water cycle is very important in an ecosystem. The water cycle is the movement of water from the ocean to the atmosphere to land and back to the ocean. An ecosystem, especially a wetland or forest, is essential to the water cycle because it stores, releases, and filters the water as it passes through the system.

There are three steps to the water cycle:
  1. Evaporation occurs when the sun heats the water in soil, rivers, lakes, and oceans, causing it to evaporate and become water vapor, which is a gas.
  2. Condensation occurs when water vapor rises, cools, and condenses to form tiny water droplets or ice crystals in clouds.
  3. Precipitation occurs when the water falls back to earth as rain, snow, or other precipitation. Most water returns to the sea or sinks into underground water sources.

The Disturbance Cycle

A regular cycle of events including fires, floods, landslides, and storms keep every ecosystem in a constant state of change and adaptation. Although the disturbance cycle can cause  disruption, some species depend on this cycle for survival and reproduction. For example, some forests depend on fire for reproduction. The cones of the trees are sealed shut around the seed with a resin that will only dissolve under very high temperatures such as those caused by fires. Another example is flooding. Flooding, in some areas like the Nile Delta in Egypt, brings rich nutrients to the soil.

Homeostasis

It is a delicate balance within each ecosystem. Competing for food, water, light, and other resources is how plants and animals stay in balance. This balance is called homeostasis.

If a new plant or animal is brought into an ecosystem, where it did not exist before, it competes with the existing organisms for available resources. The new plant or animal can out compete other organisms and cause them to become extinct by breaking the chain and thereby affecting other organisms that depended on the extinct organisms for food.

When an ecosystem functions smoothly, there are many benefits to people including healthy forests, streams, and wetlands which contribute to clean air and water. The survival of healthy ecosystems, however, is sometimes threatened by human activities that include deforestation, filling of wetlands, damming rivers, and polluting the air, soil, and water. Today, there are government agencies and other organizations that work to manage and protect Earth’s natural resources and ecosystems.

Bring it Home

Review the cycles of energy and nutrients with your students and ask that they illustrate each cycle. I’ve put together an interactive Ecosystem Cycles Flip Book specifically for this purpose – print this freebie and get started today!

If you are interested in more in-depth ecology activities, I encourage you to check out my curriculum materials:

ecology

Ecology Explorations is one of my favorite hands-on life science curriculum because it provides several opportunities to explore your local ecosystems. What better way to learn about ecology than to get out there, collect data, and experience the physical factors that influence the animal and plant communities first hand.

Estuary Ecology is a fourteen lesson unit study that focuses upon estuaries and salt water marshes. It incorporates a month-long moon observation project as well as a field trip to an estuary or salt marsh.