Chocolate Chip Levers

OK, the title is click-bait. You don’t need to use chocolate chips in this lesson but they sure are fun. I have used pennies or even beans. You simply need small objects that are consistent in weight and don’t roll.

Age level: PreK – third grade
Science Standards: for space considerations, these are addressed at the end
Materials Needed: 12-inch or cm rulers, tape, chocolate chips (or lentils, pennies, metal nuts, beans)

Levers are simple machines. That means they use few or no moving parts and can be the basis of more complex machines. Levers have been used since antiquity to lift or balance objects. In this lesson we will study teeter-totters and their kin to understand how they can be used to lift heavy objects with little effort.

Ancient Assyrians lift a stone colossus using a lever

Introduction

Identify the parts of the lever: lever arms and fulcrum. The position of the fulcrum is crucial. In the following drawing, the fulcrum is in the middle and two children of equal size balance each other. But what if one child is much larger than the other one? Or, a child wants to teeter-totter with her mother who weighs quite a bit more? In those cases, the small child might not be able to lift the larger person and the teeter-totter wouldn’t work. Think: How can this problem be solved? As students provide thoughts, ask them to draw their solutions on the board. Think about this question as you proceed through the lesson. Either the fulcrum must be moved, or the position of the people on the teeter arms must change (effectively changing the fulcrum) The teacher may or may not want to share the correct solution at this point.

One child lifts another

Capturing student interest

Show photos of extraordinary levers at work, or levers that went awry. Or provide a discordant event (see “Fun with Students”, below)

Street scene, Kabul, Afghanistan

The Activity

In this lesson, we will create a teeter-totter from a ruler; then use it to lift objects of unequal weights.

Step 1: Tape a 6-sided pencil firmly to a table.

Step 2: Balance a ruler atop the pencil. You have created a potential lever. Where are the lever arms? Where is the fulcrum? The ruler is 12 inches long. Where should you place the ruler so it is balanced on the pencil?

The ruler is balanced on a pencil fulcrum

Step 3: Only after the pencil is balanced (both ends off the table), give the students two chocolate chips. Place one chip on each end of the ruler-lever and rebalance it. Make sure the two ends are off the table. Ask students to note the length of each lever arm (6 inches and 6 inches)

Success at balancing one against one

Step 4: Only after the two chips are balanced, give the children an extra chip. Ask them how they can change things so that a single chip can balance (or lift) two chips. Tell them they must keep the chips on the end of the ruler (because you want to emphasize the position of the fulcrum and lengths of lever arms). The single chip should be on the “zero” end of the ruler for easier computation. Students should note the lengths of each lever arm.

Step 5: After students have discovered they can change the lengths of the lever arms, give them 3 more chips and ask them to balance a single chip against 5 chips. Remember to leave the single chip on the zero end and keep all chips as close as possible to the end of the rulers.

Working to balance 5 chips against 1

Assessment and Thinking

What did you do, to enable a single chip to lift 5 chips? (made that side longer). Point out that longer levers do more work than shorter levers. Another way of thinking: Pushing on the end of a lever provides more strength than pushing midway on the arm. Some manufactured levers are designed to remind you where to push.

The end of the nail clipper is marked

Who can draw a teeter-totter correctly to enable Jane and her mom to use it?

How could you correct the situation of the poor donkey and his cart (above?) Lengthen the cart arms and put the donkey at the head.

Could an ant conceivably lift an elephant on a teeter-totter? How would you do it and why would it work?

The Elephant and the Ant

Fun with students via a discordant event

Rigging the game. Before asking students to start the lesson, I make one of two rigged rulers:

Rulers painted unevenly, difference magnified for clarity
  • Use red and black poster paint to paint one ruler in two equal 6-inch segments. Paint a second ruler in the same colors but make one end longer – hopefully, not enough for students to notice on casual inspection. The line separating the two colors will be put on the fulcrum. Use the first ruler to demonstrate how to balance one chip against the other. Switch out the second ruler while distracting them. Then use a “super chip” from a special jar to lift more than one chip. Ask students to explain.
  • Use a regular ruler to balance two chips. Then switch that ruler with an identical one that has a penny taped to the bottom. In one case, a chip balances another chip. In the second case, with everything apparently the same, one chip will simply not balance the other chip. Ask students to figure it out. Note that unscrupulous merchants have rigged scales this way in the past. With modern laws and computerized scales this normally wouldn’t be a problem today.
Preschool children share a laugh at rigged ruler

Credits:
Etching of Assyrians and levers; Nineveh and Babylon – a narrative of a second expedition to Assyria during the years 1849, 1850, and 1851 by Sir Austen Henry Layard 1874

Donkey cart in Kabul; photographer known, google photos

Nail Clipper: Amazon.om

All other photos and drawings are owned and copyrighted by Camilla Barry, 2020

This lesson addresses many Next Generation core standards that carry through grade levels PreK – 12. Examples are (but not limited to):
Look for pattern and order in observations
Compare attributes of objects through measurement
Reason abstractly and quantitatively
Model with mathematics, Compare numbers
Use materials and tools to solve a specific problem
Analyze Data
Plan and Conduct an Experiment
Recall and gather information to answer a question
A problem can be solved through engineering
Multiple solutions to a problem are possible and should be compared/analyzed

Learn about spiders

Spider Web, Chloe, aged 3

October is a great time to observe spiders and their webs. Some of the best spider activity happens now, before the cold weather arrives. This lesson is suitable for PreK and K students, addressing many science standards; but adults should find it interesting, too. See the end of the article for science standards. Plus, spooky spider webs are part of Halloween lore.

Spiders are not the only insects to make silk (what other ones can you think of?) but they are the only insects that use silk to capture prey. Some spiders capture prey without proper webs, but this lesson is geared toward web-building spiders.

Spiders spin silk from a spinneret on their backside. A spinneret can make many types of silk ranging from strong foundation lines to elastic drop lines to sticky bug-catching threads. https://en.wikipedia.org/wiki/Spinneret

An orb web contains all these types of silk and is probably the most beautiful web. Here are the steps used in making this web. A teacher should draw these steps on a white board.

  1. A spider atop a twig tosses a line into the wind, again and again if necessary, till it snags another suitable twig. (for an interesting folk tale regarding this, see https://anasebrahem.wordpress.com/2013/11/15/robert-the-bruce-and-the-spider-inspiring-story-never-give-up/ This is the first foundation line.
  2. The spider walks across the foundation line, spinning a second thread.
  3. She comes back to the middle of that thread and drops to the ground, taking it with her and anchoring it so there is a Y-shape.
  4. The spider constructs a series of additional foundation lines and then radii from a central point. None of these are sticky silk.
  5. Finally, the spider spins sticky silk around and crossing the radii. Here is a picture that might be helpful: https://commons.wikimedia.org/wiki/File:Orb-web_building_steps-01.svg If you stare at this picture long enough, you will begin to wonder about the missing steps. “Wait, ” you will say. “How exactly did the spider get from steps 4, 5, and 6? I don’t get it.” You are not alone. For a scholarly article see: https://www.researchgate.net/publication/256375822_Early_stages_of_orb_web_construction_in_Araneus_diadematus_Clerck

Now, read the delightful book A Very Busy Spider by Eric Carle. Pay attention to each step of the web-building process as the plot unwinds.

Activity #1: Make your own drag line. Cut a length of cotton string about 3 feet long and tie it through the loop in a safety pin. Pin the drag line to the back of your clothing at the waist line and drop it over your shoulder to keep it from tangling if you are with other student spiderlings. Tip for very young children: have them do it in steps: 1) extend string out on floor. 2) Pick up one end and put it through the small loop, keeping the string on the floor. 3) Have them cross one end of the string over, to make a loose loop. 4) Children or teacher finish the knot, or children help each other.

Even Young Children can contruct a drag line

Activity #2: Ballooning with the drag line. If there is a group of children, have them gather close together in a ball. Imagine they are about to be hatched from a silken egg sac created by their mother, all crowded together. They chew their way through the silk. Their immediate task is to get away safely from the other spiderlings which might be tempted to eat them. So they fling themselves into the air, dragging their line behind them. It sails out through the wind, carrying them far away to a landing spot. Children love running and throwing their drag line behind them. Author’s note: October 2019 I was kayaking on the Rogue River, Oregon, when we were surrounded by diaphanous silk from hundreds of ballooning spiderlings carried by the wind. It was glorious!

Spiderling Child “ballooning” across playground

Activity #3: Using a drop line. Some spiders use this method to escape predators. Pretend you are a spider gripping the center of your orb web. You are attached to the web with a springy drop line. If a predator (say, a bird) comes near, you let go your perch and drop to the vegetation surrounding your web where you will be hidden until the predator leaves in frustration. Then you give a small yank to your elastic thread and it bounces you back into your web. Children love doing this, especially if the teacher acts like a bird ready to catch them.

Spiderling student hiding from predator

Activity #4: Go on a web walk. Before doing this, look at pictures of various types of webs spiders build. They aren’t all orbs. Some are triangle webs, tangle webs, funnel webs, sheet webs. Each one has its advantages based on location and type of prey. Look at shrubbery, around windows, under eaves and tables, near outside lighting. What types of webs do you see? Why are they built in that special location? http://ffden-2.phys.uaf.edu/webproj/212_spring_2019/Rose_Peters/rose_peters/spiderwebs.html

Activity #5: Capture a spider web to keep. This is a good activity for older children and adults. It requires patience and the willingness to try multiple times (see the folk tale about Robert the Bruce, above, about patience!). Sprinkle baby powder lightly on all parts of the web. Visually inspect the web carefully to find the foundation lines of the web. These are strong and your actions must break these lines without destroying the web while capturing it. Hold a stiff piece of black paper, larger than the web, close to the web. Position it carefully, then push the black paper firmly and quickly against the web, snapping the foundation lines while you do so. If you are successful, a beautiful web will be stuck against the paper, highlighted by the powder. You can store these webs between two sheets of photo protection, as from a scrapbook. Note: Try to take a web without a spider. Orb webs are often abandoned by spiders when they try a new location. Orb builders can build a new web in approximately an hour and collecting a web will not change their ability to do so.

Activity #6: Draw and write. Draw one of the spider webs you observed, with its surroundings. Include the prey that might be captured and the spider if you saw it. If you can’t go on a web walk, use what you learned from this lesson to draw a picture. Label the spider, the type of web, where you found it, and the prey. Date the picture. By dating your drawings, you will become more aware of when to look for spider webs.

California Science Standards Addressed (PreK and K):

K-LS1 Use observations to describe patterns of what plants and animals need to survive.

K-LS1-1 Use observations to describe patterns in the natural world to answer scientific questions.

K-LS1-1 All animals need food in order to live and grow. They obtain their food from plants or from other animals. 

K-LS1-1 Scientists look for patterns and order when making observations about the world.

K-ESS2-2 Construct an argument supported by evidence for how plants and animals (including humans) can change the environment to meet their needs.

K-ESS2-2 Use a combination of drawing, dictating, and writing to compose informative/explanatory texts in which they name what they are writing about and supply some information about the topic.

Make Flowering Hormone at Home

Humic acid , fulvic acid and gibberellic acids are important ingredients in building soils that help plants flower. In this day of internet resources, you can search for these terms and learn more than you possibly wanted to know (impossible!!) . Basic notes follow this recipe for a growth medium you can make at home, especially if you live in a farming community. It contains all three acids.

Recipe:

Collect old, dry cow manure patties. Aim for patties that have lain in a pasture for more than 1 1/2 years. It’s fun being outside! Probably want to use gloves…

Soak cow patties in a bucket of water for at least 7 days. The patties will float at first but will eventually sink to the bottom. You can also press them down with some sort of lid that is weighted with a large rock or brick. Imagine a cheese press. I didn’t bother.

At the end of 7 days or so, the water should be a rich dark brown. Pour this off into another container and add an equal amount of water. This is your fertilizer. Pour it on the base of plants.

Humic Acid: This is a powerful root zone soil builder, allowing more nutrients to be carried from the soil to the roots. It is found in decomposed organic matter, hence the reason for using well-aged manure. Humic acid also helps hold onto nutrients in the soil, keeping them from leaching away too quickly. Mycorrhizae serve much the same function.

Fulvic Acid: It is also found in materials decomposed by microbial action. Again, the reason for aged manure. It serves the same function as humic acid, aiding in making soil nutrients more available to roots. Interestingly, some people take fulvic acid internally to help boost immunity.

Gibberellic acid: This acid is useful in longer stem growth and flower production. It was discovered accidentally by scientists in Japan studying abnormally long rice stems.

More fuel for your fireplace? Some gardeners remove and dry the cow patties after making their fertilizer. Then they burn them as fuel. Would it be smelly?

5 Experiments with Tomato Starts

tomato botanical print

As discussed in a previous post, after a flower is pollinated it will produce seeds. The seeds may be inside a fruit such as a tomato. Ah, but how to get the plant to flower?

tiny tomato bud
Flower bud forming on this potted tomato

Some plants, such as the cocklebur, rely on daylight length to flower. This is called photo-period sensitive.  According to Scientific American, tomatoes are photo-period neutral, so the number of daylight hours doesn’t affect them. However, at least one amateur gardening website claims that fewer flowers are produced with less than eight hours of sunlight. You could test this idea, of course.

Most of the following activities require two identical tomato plants. In an experiment where you are testing ONE idea (i.e. number of daylight hours), it is important to keep all other things the same. I will not be repeating this in each experiment. Just remember, treat each plant identically except for the feature you are testing.

potted tomatoes

Activity #1: Photoperiod

Put one potted tomato plant outside where it would grow normally in a field. Keep an identical plant inside in a dark closet until 10 a.m. and then set it outside next to the other plant. At 4 p.m. (6 hours), bring the closeted plant back inside.  NOTE: Don’t let any light reach the closeted tomato plant during its dark period. Rather than the amount of sunlight the plant receives, photo-period actually depends on the number of dark hours. Even the slightest amount of light exposure during this period will reset the plant’s clock.

Tomatoes respond to nitrogen in either fertilizer or compost. They use the nitrogen to produce leaves and vines…but not flowers. That’s why it’s a good idea to plant your young tomato with adequate nitrogen to help it start growing…then stop. As long as the plant has nitrogen, it will continue producing more and more leaves but few or no flowers.

Activity #2: Fertilizer

Transplant tomatoes purchased in tiny pots into larger pots so they have room to grow. Give both plants a balanced fertilizer containing nitrogen when transplanting them into the larger pots (or use compost). Continue to fertilize one plant once a week but give the other plant no further fertilizer. How does their growth compare? Look for branch leaf, number of leaves, flowers.

Some tomato plants set flowers after a certain number of leaves have been produced. “Leaf” wasn’t defined in the otherwise scholarly study I read. It might have been individual leaves on a stem, or might have meant the number of stem offshoots. In addition, this study was published several decades ago and might not apply to new tomato varieties. At any rate, this is a fun project.

Activity #3: Count leaves until the first flower bud appears. More fun if you try two different types of tomato plants. Purchase them before they have begun to bloom because it’s super fun to wait for the bloom to appear. Question: why would tomatoes use this mechanism to decide when to bloom?

Apical growth can affect flower set. Apical refers to the end of the branch or stem. If you pinch off the end of a stem on a tomato, it will cause more greenery to sprout below the place where you cut, and can also force more flowers.

Activity #4: Allow one tomato plant to grow as it will, but pinch off the ends of some of the other plant’s stems and watch what happens.

Tomatoes conserve energy when they sense dry conditions. One way to conserve energy is by reducing flower production. That’s why growers recommend a steady source of moisture for tomatoes.

Activity #5: Water and Flowering. 

How would you design an experiment to test whether watering a tomato plant has an effect on the number of blossoms produced? Design and carry it out!

Highly recommended: Draw and label the tomato plants on the experiments you choose.

parts of a tomato

Next Lesson: Make your own flowering hormone solution.

 

Comments or Questions: Camilla@Rumseyhouse.com

 

 

 

 

 

 

 

Why Soap Works to Stop the Corona Virus …with activities

Soap is much better at stopping the Corona virus than alcohol. In this lesson, I may use the word “kill” for impact, but nothing actually kills viruses, since they aren’t alive. But you can blast them apart so the little buggers can’t harm you.

Soap has been used for centuries…how did people come to discover it? One theory says that it was discovered at the foot of mountainside altars where animals were sacrificed by burning. Fat and ashes accumulated in the clay soils around the altars. People in the middle east still use types of clay for washing and women might have gathered some of the clay near the altars for doing their laundry at the river. They noticed that the clay mixed with water, fat and ashes cleaned better than clay alone. Water, fat and lye from ashes is a basic pioneer recipe for soap. Author’s note: I bought some bars of clay for washing in the street markets of Afghanistan.

Here’s the thing about soap molecules: one end of the molecule likes to attach to water; and the other end is repelled by water. The hydrophobic (water fearing) end attaches to dirt and grease. The water-loving end (hydrophilic) attaches to water molecules. We haven’t gotten to the virus killing aspect yet.

Here’s a drawing I like to show students about the soap molecule. After explaining, we play a game.

soap molecule dirt water

Activity: Soap grabbing dirt game

I play the part of a soap molecule and the children are dirt and grease. I point out a door which represents a sink drain. I run around the room, with one hand held out looking for a water molecule (which might be imaginary or could be another teacher) and my other hand grabs onto children (dirt and grease) in a long chain. Soon we are running around the room, the soap molecule having scooped up all the dirt and grease. Then my other hand finds the water molecule (I’ve either explained that it’s imaginary or I grab onto another teacher who plays the water) and we are all flushed down the sink and out the door. They love playing this game, giggling at being dirty grease.

kids playing soap game

Activity: Get Dirty

A natural follow-up activity is to ask the children to get their hands really dirty (how fun!) and then use a bar of soap and water to wash themselves clean – then watch the dirt go down the drain.

At the end of this post are other activities that involve soap.

 

But now, why does soap kill the corona virus? You remember the water-loving end and the water-avoiding end of the soap molecule. Ah. The hydophobic end (water-avoiding) not only picks up dirt. It can also puncture a virus membrane, splitting it apart. Presto: virus destroyed. Soap is the only ingredient that is so effective at ruining virus. It is good at splitting apart the molecules of that membrane.

soap molecule killing corona virus

When you wash your hands using plenty of water and soap, and then completely rinse the water down the drain, the dirt and virus bits are taken with it. Of course, this only works on skin you have washed. You might want to wash your face, too.

Activity: Wash with various water mixtures instead of plain water

Not all waters are equal. Try sudsing your hands first with tap or well water. Observe the amount of suds – or better yet – watch as someone else suds their hands and draw what you see for reference or take a photo. Then try washing your hands with salty water or water with dissolved epsom salts. Is there a difference? Which would be most effective at cleansing? The more suds, the better the cleansing effect.

Activity: Wash your hands with soap root.

This California native plant grows everywhere along roadsides and pastures. The leaves are long and wavy. The bulb can be dug up with a pickaxe. Remove the hairs from the bulb. Have a tub of water ready. Mash up the bulb using two stones. Put the mashed up pieces into the tub of water and rub vigorously between your dirty hands. Suds! Note: I tried washing with soaproot for years unsuccessfully by simply rubbing the bulb between my hands. Nothing. It is only when you crush it that you release the saponins. Experiment makes perfect!

saoproot leaves

soaproot bulbs

Activity: Make Jelly Soap

Here’s a sorta silly recipe, but one that might encourage kids to wash their hands more often: Jelly Soap.

Pour 1 Cup boiling water over one pouch unflavored gelatin (.25 ounce). Stir to dissolve. Then slowly add 1/2 Cup liquid hand soap into the gelatin mixture, stirring very gently because you don’t want bubbles. Food color is optional. Pour the mixture into silicone molds and let set overnight. If you don’t have silicone molds, just pour it into any small cup and scoop it out the next day when it has set.

jelly soap
jelly soap

Search for a long-lost recipe…and hours of unsuccessful (but fun) experimentation:

When I was a Girl Scout leader in the 1990’s, I came across a science experiment in the Brownie Scout manual which I followed successfully in both my troop and science classes. The basic idea was to mix salt with liquid soap. The soap would curdle and solid chunks float to the top, which could be scooped off and molded into new “bars” of soap.  The science wasn’t explained in the Brownie manual, but I researched it and discovered it was an excellent connection to chemistry and the history of Castile soap. Castile soap historically was a liquid soap made in Spain from olive oil and the ashes of plants such as pickle weed found in salt marshes. These ashes produced potassium hydroxide and the resulting soap is always liquid. But liquid soap was difficult to transport and it was desirable to find a way to make it solid. Now we know that ashes made from hardwood produce sodium hydroxide and the resulting soap is solid. But the producers of liquid Castile soap hadn’t discovered that. Instead, they discovered that adding salt to liquid soap would curdle it, which they could mold into hard soap. Voila! That was exactly what we were doing when we added salt in my Brownie troop.

Alas, I cannot find that experiment anywhere on the internet and I no longer have that out-of-date Brownie manual. It was so fun, easy, and historic. I spent hours over the past couple of days researching and experimenting on my own and did eventually find that I could add salt directly to Dawn dishwashing detergent and come up with a sort of goo. Here’s a photo. If anyone has an old Brownie manual, I’d love to find the original experiment. You might also want to try adding salt to various liquid soaps and see what happens.

dawn and salt goo

 

 

 

 

 

 

How Plants Attract Pollinators

Pollination is the transfer of pollen from the male part of the flower to the female part of the flower so that a seed can be formed.   Pollinators include (but are not limited to) butterflies, bees of all sorts, moths, beetles, mice, bats, and even wind.

Student Drawing of a Butterfly Flower

Notice that a flower is necessary for pollination, but not all flowers are equal. Flowers that are attractive to pollinators are more likely to produce seeds. In this lesson, students will learn what pollinators seek when they visit a plant. Flowers that match pollinators’ desires stand a good chance of being pollinated by the visitor. This is because the visitor (bat, bee, etc.) may unwittingly transfer pollen from the male plant part to the female plant part and pollination occurs.

So many lessons can be based upon this today’s lesson; this is just an exploratory lesson to help students see flowers in a new way. Spring is an excellent season for the lesson. It can be eye-opening!

Science standards are noted at the end of the lesson.

Lesson activity:

  1. The instructor reads through the pollinator descriptions and cuts them into separate slips, duplicating some if necessary so that each student or group of students has a pollinator slip. The descriptions are written from the viewpoint of the pollinator since it’s often more fun for students to actually assume the role. The descriptions follow.
  2. Ask the students to read the slips carefully, then draw and color a flower type that would attract that pollinator. The flower does not have to be a real flower; students should use their imagination to build a flower using the clues. Use labels if necessary to supplement the drawings. Discuss how students might indicate such features as “odor” on their drawings, or time of day. Add the name of the pollinator to the drawing, or show it visiting the flower. Give your flower a name.
  3. After students have completed their drawings, ask them to share their drawings with the class and explain how the flower would attract their pollinator.

    student drawing of a fly-pollinated flower
    Student drawing of an imaginary flower that a fly might visit

honey bee pollinated flower by student
Student Drawing of an imaginary flower that a honey bee might visit

 

You are a moth. You come out at night, and have very poor eyesight. Flowers that glow or reflect light may attract you. Light-colored flowers that show against the night sky are best. Fragrance helps you find the flowers. You have a long tongue and can reach deep into flowers. You need lots of nectar to keep you warm during the night, so flowers with lots of sweet nectar are a true gift. It’s especially nice if these flowers only open at night, so other pollinators don’t get to them. You don’t care so much about pollen.

You are a honey bee. You need both pollen and nectar. Pollen for protein and nectar for energy. You can figure out tricky flower mechanisms to get what you need, burrowing inside. You have a short tongue so flowers with deep nectar tubes are troublesome; sometimes you just bite into the back of the blossom!  Your eyesight is not precise, so you like masses of flowers, especially yellow and blue. Fragrance, color and hidden ultraviolet markings help you find the flowers and nectar. You need a landing pad on the flower, or a place to grab while feeding on nectar. You feed during the day. You can hang upside down if necessary.

You are a fly. You like smelly plants, or ones in the brown color range. Perhaps these flowers remind you of rotting meat. You look for easy, flat flowers for landing. You fly during the day. You have a short tongue, so you can’t reach nectar in deep flowers.

You are a beetle.  You like big groups of small white flowers, or brushy flowers so you can grip easily.  Some flowers which look like a single “bloom” are actually clusters of tiny flowers which beetles like.  You can’t fly well, so you want flowers with lots of pollen grouped together in one spot.

You are a bat. You fly at night, so flowers that open after dusk are favored. White or light-colored flowers attract you most, and ones that have lots of nectar to help you through the night. It’s also very nice if the flowers are lifted up into the sky. Sweet smelling flowers attract you.

You are the wind and you go where you will. Although you pollinate many flowers, you don’t give a hoot about flower shape, color or scent. However, flowers that make their pollen openly available and flowers that produce lots of pollen are more likely to be pollinated by you.

You are a butterfly. You like to test flowers for nectar by tasting with your feet, so flowers that are flat provide a handy landing pad. Yellow and blue  flowers are especially attractive. Some butterflies swarm around bushes with large spikes of blue flowers because they can move easily from one small flower to another. Nectar is more important than pollen for you. In fact, you can’t eat pollen because your mouth part is only a long tube. You only venture out on warm sunny days.

Teacher notes and extensions:

  1. Wind-pollinated plants often have non-showy or green flowers, such as grasses and some trees. Don’t tell the students this in advance, let them puzzle it out for themselves.
  2. After the exercise, go on a flower walk and look for pollinators – or discuss which type of pollinator they are most likely to attract. Students will be so much more knowledgeable after designing their own flowers
  3. Bring in a selection of flowers in vases. Ask the students to do their best to match flower to pollinator.
  4. Look up pollinator mouth parts, wings and legs on the internet or in books. Discuss how these parts help the pollinator gather nectar and/or pollen.
  5. Look up a simple flower diagram and find which parts produce pollen, receive pollen, and produce nectar.
  6. Taste nectar from flowers such as honeysuckle, clover or nasturtium.
  7. The pollinator notes are very basic. You can search for more information on plant-pollinator interactions in many books or the internet.

Science Standards:

  1. Understanding how plants and animals adapt to their environment.
  2. Understanding flowering parts and seed production.
  3. Learning to communicate scientifically with drawings, labels and oral presentations.

 

 

Exploring Toyon Trees and Birds

I have put together a multi-disciplinary lesson plan that can be extended almost indefinitely. My lesson was inspired by a scientific article concerning the cyanide in Toyon berries, and I went from there to an article in Bay Nature Magazine, which is reproduced below. The basic article is about which birds eat Toyon berries, but I have included suggested activities throughout the article that incorporate nature study, bird anatomy, ethnobotany, math and measurement, critical thinking.  No special materials are needed, the lesson gets kids outdoors and involves them in research and artwork. *See upcoming lesson: How Native Americans used California Plants

cedar waxwing eating berry

The article is black, my activities are in blue italics. Activities are suitable for many different grade levels. I hope you enjoy it. 

Ask The Naturalist: How Important Are Red Toyon Berries To the Winter Food Chain?

From Bay Nature, by Alison Hawkes and Alan Kaplan

December 22, 2016

The bright red berries of the toyon plant make this native perennial shrub a festive feature of the winter season in California. These leafy bushes are common in chaparral and oak woodland habitats, but they are also well loved garden plants given their drought-tolerance and attractiveness for much of the year as the summer bloom of small, white flowers turns to an abundance of red berries in the fall, carrying well over into the winter months. Of course, we’re not the only ones who love those berries.toyon berries

Activities:

Look up a picture of Toyon. Do you have this plant in your yard or neighborhood? It is very common in the Capay Valley.

Go on a walk to see if you can find a Toyon. Draw it, including leaves, stems, berries. Use colors. *See upcoming lesson: completing a science drawing

If you find a Toyon tree, what stage is it in? Are there berries, flowers, or neither? 

Are there any animals/insects feeding on the leaves, flowers, or berries? See what you find. Can you identify them? Make a list next to your Toyon drawing.

Bay Nature put this question to Alan Kaplan, a retired East Bay Regional Park District naturalist and birder: How important are toyon berries to the winter food chain? 

Wintering birds in our area often depend on the fruits of native and exotic (ornamental) berry plants to sustain them. Three common fruit eaters are American robin, cedar waxwing, and hermit thrush.

cedar waxwing

Activities: 

Look up photos of these birds online. Can you find these birds  in your yard? 

What does “ornamental” mean? Can you find both ornamental and native plants in your yard? How were they planted? By hand, or did they arrive some other way? 

In the 1970s, ornithologist Stephen Bailey looked at how these birds use berries in winter and how they interact with each other. (He was a graduate student at UC Berkeley at the time.) He found that toyon (Heteromeles arbutifolia) was the most important source of berries for robins, thrushes and waxwings, though they also make use of other berry plants on the university’s campus, such as cotoneaster, privet, pyracantha, holly and juniper.

Low in protein and calories, berries offer limited nutritional value, especially to small birds who need to consume their body weight in food each day to survive the winter. For example, a bird would need to consume 3 ounces of (dried) toyon berries to get the same 331 calories that could be had with only 2 ounces of sunflower seeds. Nevertheless, if you’re a wild bird you take what you can get!

Activities:

How do protein and calories contribute to nutrition? Why are each important? What foods do you eat that are high in protein or high in calories? 

Use a measuring cup to discover the amounts for 3 ounces and 2 ounces. A scale could also be used. 

Which food (toyon berries or sunflower seeds) gives the most calories per serving? Do you eat either of these foods yourself? Ripe Toyon berries were used by Native Americans for food, beverages and medicine. *See coming lesson: making a calorimeter

Bailey found that he could learn a lot about bird behavior by watching them tackle a berried bush. Each of the three species he studied — American robin, cedar waxwing, and hermit thrush — had a different strategy of getting its fill. Each competed with the others and none could exclude the others altogether.

The large American robin throws its weight around, dominating the other birds when defending a rich bush of berries against individual hermit thrushes or a small number of cedar waxwings. Cedar waxwings, in turn, overwhelm the defense of robins with their large numbers, making up with flocking what they lack in fierceness.

Both the robins and waxwings prefer to perch and pluck at berries within reach, and spend about 16 minutes at a time doing that. Robins take five berries during that time, and cedar waxwings take three. A robin might eat its weight in berries in a day (about 3 ounces), filling and emptying its crop three times per hour. These birds must eat so much because the nutrient content of their food is low, and they digest it very rapidly (so less of the nutrients are absorbed).

bird anatomy

Activities:

What is a “crop”? Look up the anatomy of a bird. How does a crop help a bird digest food? Do other animals have crops? *see upcoming lesson: Earthworm habits and anatomy

Use a timer or clock to discover how long 16 minutes takes to pass. If robins eat 5 berries in 16 minutes, approximately how many minutes does it take to eat one berry? If cedar waxwings eat 3 berries in 16 minutes, how many minutes does it take to eat one berry? Which bird eats the fastest? Why do you think different birds eat at different rates? *See upcoming lesson: Pendulums and time

Think about the phrase “they digest (their food) very rapidly – so less of the nutrients are absorbed.” How and why is food digested in your own body? Are some foods digested more quickly than others? Consider simple sugars and more complex sugars such as contained in potatoes. Where are nutrients absorbed into our bodies? Stomach, intestines? *See upcoming lesson: Walk through the human digestive system.

human digestive system

Hermit thrushes skulk around very carefully and zip in and out of a bush, bagging one berry at a time from under the nose (beak) of the dominant robin. Robins and thrushes will also take fallen berries from the ground (waxwings will not), but the hermit thrush remains a sneak thief most of the time. It only gets about two berries per bout of feeding, but it, too, eats its weight in berries each day. The thrush would prefer to stay deep in a berry bush, eating as inconspicuously as possible. Some of the robins and thrushes do spend the entire winter in a single bush if it is rich enough in berries.

As the season progresses and food becomes scarcer, robins become more territorial and aggressive, and cedar waxwing flocks become larger in response.

american robin

Do plantings of toyon and exotic berry-bearers make a difference to overwintering birds? Yes! Populations of overwintering fruit eaters are more stable and more reliably found because there is a regular supply of berries. Fruit put out at bird feeders and ornamental plantings around homes have helped the northern mockingbird expand its winter range in the West (the seed-eating cardinal has profited similarly in the East). Shrubs, planted as ornamentals around homes, can be easily defended from other birds. The larger and more conspicuous the planting, the greater its chances of attracting cedar waxwings and American Robins.

And that is exactly why the plant produces its attractive berries in the first place (usually reddish and blackish colors predominate, though we don’t know why). The toyon goes so far as to have the short stems (pedicels) bearing the berries turn bright red, to be extra attractive to fruit-eaters and ensure that all the berries are eaten.

Activites:

Did your drawing of the Toyon include colors of the berries and also the stems? 

Plants don’t have “intention”, but they do reproduce better by attracting animals. Why would a plant find it advantageous to attract birds to its berries? *See upcoming lesson: Seeds and their dispersal

Plants can also attract animals to their flowers. Why would it be beneficial for plants to attract animals to their flowers? An entire lesson can be done on this topic! *See upcoming lesson: How plants use flowers to attract pollinators

Berry eaters digest the nutritious coating and excrete the seed intact, helping it with a bit of fertilizer for a good start! Seeds are excreted away from the parent plant, reducing competition for water and sunlight.

For a lesson in food chain dynamics, go ahead and observe a local berry bush this winter. Note the abundance of fruit as the season begins, and then watch the change in the number of berries through the winter. You may be lucky to see a flock of cedar waxwings settling down to a mid-winter feast as the resident American robin tries in vain to beat them back. And, lurking nearby, ever ready to dart out for some really fast food, could be a hermit thrush.

More Information from the Los  Angeles Times:

The berries of Toyon are actually poisonous to birds if eaten unripe. This is because there are two compounds in the berries that combine to form cyanide if the berries are crushed while green. When birds peck at green berries, cyanide gas is formed and birds leave them alone. It is only when the berries are fully ripe and red, that cyanide is naturally removed and birds can safely eat them.

Activities:

What would be the advantage to Toyon to produce cyanide while the seeds are unripe?

What is the difference between liquid and gas? How would the bird most likely sense the cyanide, taste or smell? *See upcoming lessons on states of matter, and smell testing.