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Eastern Chipmunks Love Acorns

Driving down my road I occasionally see these little creatures shoot across with tails held straight up. These are Eastern Chipmunks.

Both chipmunks and ground squirrels live in Missouri. The ground squirrels are bigger with different coloring and don’t seem to live in my valley.

Except for an occasional sighting chipmunks aren’t noticed much either. My cats catch those that move into the yard. Their favorite routine is to bring the chipmunk into the house and let it go.

Cats do have a sense of humor and must enjoy watching me try to corner a terrified little rodent, scoot it into a container kept ready for such emergencies and slam the lid on. The chipmunk is then carried off down the road beyond where the cats normally go and turned loose.

For some reason I had believed eastern chipmunks, like woodchucks, hibernated during the winter. So I was surprised to see several of them busy gathering acorns on a walk down the road.

Chipmunks do not hibernate. They do stay home in their burrows in cold weather. This means they must gather up a supply of food to snack on. Acorns are popular snacks.

That is exactly what these busy creatures were doing when I noticed them. It was hard to not notice one of them.

Most wildlife wants to avoid people. The birds keep flying off to a tree further down the road. Deer bound off white tails waving. Squirrels streak up the trees.

eastern chipmunk eating acorn — Being a rodent, the front gnawing teeth have enamel only on the front which grows continuously. Gnawing on things like acorns wears it away and keeps it razor sharp. The fingers are long on all four paws and have good nails for digging burrows. What most people see is how cute they are.

Eastern chipmunks often do take off and are only rustling in the leaves. One was determined to get another acorn. It darted across the road about ten feet in front of me, stuffed two acorns in its cheek pouches, sat on a fallen branch to assess what I was up to and darted back across the road.

The little rodent didn’t go far. It raced up a fallen tree and across to a perch on another fallen branch to eat an acorn. I assume it was the same one. I saw two or three others in the area.

The next morning was twenty-five degrees. It warmed up quickly and I went walking. The chipmunks had all stayed in their burrows.

Fall Into Winter Begins

Nature really has only two seasons in the Ozarks. One is growing season. The other is winter. Now the Ozarks is waiting to fall into winter.

Most plants still look green. Looking carefully there is a yellow cast hiding under that green. The few cold nights have turned some plants like the dogwoods to fall colors.

fall into winter foliage and color — Leaves are turning red as sunflowers and asters bloom. The growing season will continue until killing frost turns the plants black one morning.

Wait a minute. Isn’t fall another season? It is for people. For plants it is still part of the growing season as they busily make seeds and store sugars and starches down in their roots for the coming winter.

Green chlorophyll doesn’t photosynthesize well in cooler temperatures so the anthocyanins take over. These come in colors other than green.

For turkeys, deer, squirrels and other such creatures the fall into winter means an abundance of seeds and nuts to gather. They don’t care about colors in the leaves, only in eating and hiding enough of this bounty to survive the winter.

deer waiting to fall into winter coat — Still in the golden brown summer coat this young white tailed deer stands in a patch of sunlight along the road debating whether to flee. The notched ear indicates this one has had a close call in the past. She needs to learn to flee from people fast as hunting season opens soon.

The deer are putting on their dark brown winter coats. The raccoons are retiring up into the hills.

Birds are more mobile. Many of them are following the warmth south. One by one the hummingbird feeders are being cleaned and stored. Migrants are stopping by to stock up on sunflower seeds for extra energy giving us a chance to see some new birds.

The usual residents are ignoring the feeder as they load up on other delectables. This excepts the morning doves who leave standing room only on the feeder in the morning.

The turkey vultures are gathering and soaring in lazy circles as they drift south. The goldfinches have shed their gold feathers and are dull green now.

River oats — One of the easiest grasses to identify, the flat seed clumps are unique. At the end of the growing season they dangle glowing gold in the sun and tremble in the breeze.

The winter visitors haven’t arrived yet. These are the juncos, various sparrows and titmice.

The days are getting short. The temperatures are warm all day and cool at night. All it will take is a good rain and the Ozarks will fall into winter.

Meander through the seasons in photographs in “My Ozark Home.”

Shelf Mushroom Appear For Spring

Spring has arrived with rain and warmer temperatures. This brings out the shelf mushroom crops.

shelf mushroom on log — A storm several years ago knocked over this large tree down by the river. The road crew cut it up and rolled the pieces off the road and into the edge of the woods. Walking by I noticed the crop of shelf mushrooms. The fresh ones are light in color. As they age, they darken. All are tough.

There are many kinds of shelf mushrooms. They are not all in the same mushroom groups for many reasons. I’m not very knowledgeable about mushrooms so I tend to look at them the same way.

shelf mushroom from top — The size of the fan may vary. The thickness may vary. The edge may be smooth or ruffled. All shelf mushrooms are semicircles.

The shelf mushrooms I see are on dead or dying trees. They jut out with a half to two thirds circular shelf. Underneath is a stem joining the shelf to the tree.

gilled shelf mushroom — This shelf mushroom has gills under its cap.

Some of the shelves have gills under them. Others have pores that look like tiny holes under them. This is why they are split into different groups.

pored shelf mushroom — Under this shelf mushroom cap is a spongy surface of pores.

The shelves are different. Some are thick and woody. Some are thin. Some are in piles. Others are separate. Some are pink or blue or lined.

Size varies too. Some are barely an inch across. Others are small plates.

Some of these mushrooms are found only in particular seasons. Others can show up anytime after a nice, warm rain.

I think this is a mound of salmon shelf mushrooms. They were on a tree stump. They are supposed to be edible, but I hesitated as I wasn’t positive of my identification.

People do eat some of the shelf mushrooms. Chicken of the Woods and Oyster Mushrooms are two of the favorites. These are fairly easy to identify definitely.

Some of these mushrooms are poisonous. Most are ones no one would want to eat due to bitter flavor or woody texture.

For myself, I don’t hunt for shelf mushrooms to eat. I browse through the mushroom guides and see that many of the edible ones are too easy to confuse with others listed as not edible.

pink shelf mushroom — The soft pink color seems to glow for these shelf mushrooms on a fallen log.

A trusted friend did give me some Chicken of the Woods once. This shelf mushroom can form huge piles of shelves. It was good. I don’t trust myself to identify it on my own.

Spring brings up many mushrooms much easier to identify. Another month brings morel season. That is one mushroom I can identify confidently.

Find out more about Ozark nature in “Exploring the Ozark Hills.”

Paradoxa Native Plant Walk

Sunday afternoon was a pleasant escape from cleaning up after six inches of rain with the high water that followed. Paradoxa, the Rolla chapter of the Missouri Native Plant Society, held a winter tree identification walk.

Finding trees is easy in the Ozarks. They tend to be big and hard to miss. Over the winter most trees are bare trunks and branches.

For someone like me who depends on leaves and flowers to identify a plant, bare trunks and branches are daunting. Where do you start?

Bark helps identify a tree in winter. The Osage orange bark (left) is yellow with long ribbons intertwined. Shagbark hickory (center) has long, thin plates of grey bark. American elm (right) looks like well worn gray pavement.

As the Paradoxa group wandered around looking at the different trees, several important things to look for became obvious. First was bark.

All trees have bark. Take a closer look at the bark. Bark is not usually smooth and featureless. Bark has color, texture and furrow patterns. The combinations help identify the tree.

Terminal buds are another help in identifying a tree in winter. Osage orange (left) has small buds on a big bulge. Post oak buds (center) have shingled scales and a gang of buds. Shagbark hickory (right) has a single large bud with two scales, one on each side. This bud is starting to open.

A second characteristic is the terminal buds. When a tree goes dormant in the fall, it makes leaf buds covered by scales on its branches. The one on the tip of a branch or twig is the terminal bud.

Some buds have many small scales giving the bud a shingled look. Others have two scales, one on each side.

Some trees have a single terminal bud. Other trees like to have groups of buds.

Two retired forest service men led the Paradoxa group on their winter tree identification walk.

The Paradoxa group looked at the bark and buds. Some were easy like the black walnut. Others were hard.

Where do you go for the hard ones?

One place is the winter tree guide published by the Missouri Department of Conservation. The Missouri Trees guide has the bark and buds in it.

The Paradoxa group includes people of all ages. Many are Master gardeners or naturalists. All are interested in Missouri native plants.

The more interesting place to go is on a guided walk like the one Paradoxa held on Sunday. Everyone on the walk is interested in Missouri plants. Each person knows a different set of plants.

As we walked along, we made comments about the different trees. Those who recognized the tree helped those who didn’t spot the best ways to identify it in the future.

The Missouri Native Plant Society has chapters like Paradoxa in many parts of Missouri. Anyone interested in Missouri plants will find joining the groups helpful and fun.

Yellow Ironweed Verbesina alternifolia

Yellow is the color of late summer in the Ozarks. Yellow Ironweed is one of the many yellow wildflowers blooming along the roads and in the pastures from august to killing frost.

Verbesina alternifolia Britton ex Kearney

August to October N Family: Asteraceae

Tribe: Heliantheae

yellow ironweed flower

Flower: A profusion of yellow flowers top short stems forming a loose head at the top of the plant. Not all of the flowers bloom at the same time. Each flower head has up to 10 bright orange yellow ray flowers sweeping down from the globular mass of yellow tube flowers. These are up to half an inch long and stick out individually.

yellow ironweed side flower

Leaf: The leaves are usually alternate but may be opposite in part or all of the plant. The lower leaves may have a short, winged petiole but upper leaves are sessile. each leaf has a slow taper to the center and a slow taper to a sharp point. The leaf top is darker green than the bottom and begin to take on a yellow tinge as the leaf ages. Both sides have a sandpaper texture.

yellow ironweed leaf

Stem: A single stem grows up to 8 feet tall. The only branches are at the top leading to flowers. The green, ridged stem is winged with white hairs between the ridges and wings.

yellow ironweed under leaf

Root: The perennial roots are fibrous and have stout rhizomes so the plant forms colonies.

yellow ironweed stem

Fruit: The seeds develop inside a cage formed by the remains of the tube flowers. This opens to release the flat, brown seeds with small wings along their sides.

yellow ironweed fruit

Habitat: This plant prefers sunny places but will grow in light shade. It likes good soil with moisture as in lower pastures, along roadside ditches, along streams and bases of bluffs.

Yellow Ironweed

yellow ironweed plant

Yellow Ironweed has thick, stiff stems letting it tower over most other plants growing nearby. The stems are tough enough to withstand wind and remain upright. This lets it grow wherever it finds the right soil and moisture level.

The tall stems are popular with various vines. False buckwheat, partridge pea, hog peanut, woodbine, morning glories and more twine themselves around the stems and bind several plants together.

Recognizing this plant is fairly easy not only because of its size but by its flowers. The color is vibrant yellow. The back swept rays are irregular in number and arrangement. The globular crown of long, yellow disk flowers sticking out is totally different from the other aster family members. In those the disk or tube flowers are packed close together. Yellow Ironweed tube flowers are separate individuals.

This plant is determined to bloom and produce seeds. Even when the top is eaten off, the lower leaves send out new flower stalks. These will bloom on plants now only two feet tall. The leaves and stem tips do seem popular with deer.

The leaves are large and feel rough. As the plant blooms into the fall, the leaves take on a yellowish green color. The lowest ones turn yellow and drop off.

Yellow Ironweed forms colonies and seeds itself prolifically. These form yellow clouds of flowers along the roads and in the pastures from late summer into fall until frost kills the plants.

Wood Sage Teucrium canadense

In May single, thick, square stems appear pushing their way through the dense crowd of plants. In June conical spires of flowers top the stems and the first ring of pale lavender, almost pinkish, flowers open. The Wood Sage is in bloom.

Teucrium canadense L.

June – September N Family: Lamiaceae

wood sage flower

Flower: A flower spike surrounds the top of the stem in whorls of two to six flowers. Green calyxes surround the bases of the flowers. Each flower has a large, white to pale lavender lower lip with dark purple mottling near the throat of the flower. Two short upright petals flank the lower lip like ears. The four stamens and pistil arch up over the lower lip. The edges and undersides of the petals are covered with short hairs.

wood sage side flower

Leaf: Opposite leaves have short or no petioles. Two leaf lie bracts spread out at the base of each leaf. The leaf is long and widest toward the middle and tapers to a point. The edges are toothed. Short hairs cover the top and bottom surfaces of the leaves. The mid and side veins form strong cords on the underside of the leaf.

wood sage leaf

Stem: Stiff square stems grow three to four feet tall. Fine short hairs cover the stems. Rarely the stem branches in the upper half.

wood sage underr leaf Root: The roots are fibrous and perennial. There are rhizomes so the plant forms colonies.

wood sage stem Fruit:

Habitat: This plant prefers open, sunny areas with moist soils such as along creeks, roadside ditches and prairies.

Wood Sage

American Germander

wood sage plant

Wood Sage can be considered a weed. A single stalk appears one year. The next year the one stalk has become a small colony. Other single stalks appear nearby. In a few years Wood Sage covers the area.

Various smaller native bees don’t mind this abundance of food. They zero in on the purple splotches on the lower lip of the flowers and land to feed. For people, the flowers have no scent.

The flower spikes can be eight inches long. The tall stems bring the flowers up to where they are easily noticed. The flowers are small at three quarters of an inch long but are interesting to look at with their little ears.

Wood Sage is occasionally planted in native gardens. As with other mints, this one must be confined or it will take over the garden. It is a hardy plant tolerating some drought and crowding by other plants.

I find Wood Sage along the roads where it thrives even when surrounded by giant ragweed, blackberries and poison ivy. It does like lots of sun and withstands hot temperatures. The flower spikes make it an easy plant to identify.

Enjoy more nature essays about the plants, animals and events of an Ozark year in Exploring the Ozark Hills.

Physics 13 Using Rollers

Remember a simple machine doesn’t change the amount of work you do. You will still move an object the same distance. What a simple machine does is make that work take less effort. Are rollers a simple machine? What are rollers anyway?

These are not the kind girls use to curl their hair.

roller project materials

Question: How do rollers work?

Materials:

Book

String (scissors to cut it)

Rubber band

Six or seven round pencils

Procedure:

Wrap the string one and a half times around the book

I used a smaller book. The book could be twice as thick and this project will still work.

Cut off the piece of string

Tie a loop in one end of the string

The loop can be an inch or a little more long. If it is less than half an inch, it will be harder to attach it to the rubber band.

Put the other end of the string through the rubber band and the loop

The end of the string goes through the rubber band first and then the string loop.

Pull the string tight

The string loop must be pulled tightly to the rubber band so it will not slip pulling the book later.

Tie the string around the book

The string should be tied around the middle of the book so it will pull evenly across the table.

Use the rubber band to pull the book across the table

Set the book back at the beginning

The pencils should be fairly evenly placed so the book can move from one to the next without falling off.

Space out the pencils so three will be under the book and the others in front of it

Set the book on the last three pencils

Use the rubber band to pull the book across the pencils

Observations:

Describe how the rubber band behaves as you pull the book on the table

Pulling the book across the table creates friction for the entire surface. Friction makes the book harder to pull.

Describe how it feels pulling the book on the table

Describe how the rubber band behaves as you pull the book across the pencils

Describe how it feels pulling the book across the pencils

Conclusions:

Assuming you pulled the book the same distance both times, did you do the same amount of work? Why do you think so?

Was it easier to pull the book on the table or on the pencils?

The pencils roll as the book is pulled over them making the name rollers apt.

What did the pencils do under the book as it went over the top of them?

Why would the pencils be called rollers?

Can you think of another name for a roller? What is it?

What I Found Out:

My book had a slick book cover on it so it pulled across the table easily. The rubber band stretches out at first then sprang back once the book started moving. The book dragged a little on the table.

The rubber band barely stretched before the book started pulling over the pencils. It moved very fast over the pencils. The book didn’t drag at all.

The pencils do roll but some roll better than others. They are not attached to the book so they bunch up losing their spacing.

Since work is the distance times the mass, I did the same amount of work. The mass of the book and the distance did not change with and without the pencils.

What did change is how easy it was to pull the book over the pencils. The pencils turned and rolled under the book.

The pencils could be called rollers because that is what they did: rolled. Something else that rolls is a wheel.

Butterfly Weed Asclepias tuberosa

Butterfly weed, Asclepias tuberosa, is fast becoming a popular garden flower. It is one of the most easily seen and recognized of Ozark wildflowers.

My goal with these plant pages is to present information on a plant plainly. This post is set up for easy viewing online but includes the information and pictures used on the actual pages about butterfly weed.

I would appreciate any feedback you may have on this information either through the comments section or the Contact Page [this may be more reliable].

Asclepias tuberosa L.

May to September N Family: Asclepiaceae

butterfly weed flowers

Flower: Flowers range from lemon yellow through most commonly orange to red. The corolla is backswept. The five wells have the outer wall elongated and standing upright. The five horns arch over to the central disk. The flowers are in flat topped umbels from the tips of branches and nearby leaf nodes.

butterfly weed flower umbel

Leaf: The leaves are alternate and sessile. The top surface is dark green. The under surface is light green with a prominent midvein. The other veins are in a network. Short hairs cover the leaves especially the edges and veins.

butterfly weed leaves

Stem: The stem is hairy and ranges from green to purple. It goes up then bends over often with a branch or two.

butterfly weed stem

Root: This plant has a rhizome.

butterfly weed seed pods

Fruit: Each umbel can produce several long seed pods. They tend to stay slender with a groove down one side. They are covered with short hairs and ripen to a purplish brown. The groove splits releasing the tufted seeds into the wind.

butterfly weed seeds

Habitat: Butterfly Weed loves the sun. It grows along roadsides, in pastures, glades, open ground. It is often in drier areas.

Butterfly Weed

Chigger Flower, Pleurisy Root

butterfly weed plant

Asclepias tuberosa is a perennial so the plants show up in much the same places every year. Their flower color is so distinctive I watch for it trying to spot the first one to bloom.

Most butterfly weed around here is vivid orange. Some are paler, more yellow or even true lemon yellow. Some are deep red.

Some special flowers are two toned. They open as yellow. The backswept corolla remains so but the wells darken to red. These flowers are quite striking.

The greatest enemy of these plants is the roadside brush cutter. Unlike other milkweeds, butterfly weed will try to grow new stems and bloom again. It takes its toll on the plants and these may disappear after a few years.

Some of the older people in the area have successfully transplanted a special plant to their home. The fleshy fragile rhizome makes this very difficult. Failures are more common than successes but not mentioned.

The easiest way to have these plants in the home garden is to start them from seed or purchase nursery plants. I was told the plant can be propagated by layering as well. The low growth habit, prolific blooming, vivid colors and attraction of butterflies have made this a popular garden plant.

Although larger butterflies will stop by, I’ve seen pipevine and tiger swallowtails, most of the butterflies are smaller. Pearl crescent, little sulfurs, various skippers and gray hairstreaks hang around them creating a multicolored cloud. The usual wasps and bumblebees tromp around pollinating the flowers.

This milkweed is unusual in two ways. It has alternate leaves. It has clear instead of milky sap. Monarchs do lay eggs on it. Their caterpillars do seem to mature on the plants.

Whether growing wild or in a garden, butterfly weed is worth stopping and admiring.

Physics 12 Double Levers

Scissors are so useful. They are one of several common double levers.

Take a look at a pair of scissors. Each blade moves like a lever: one end goes down pushing the other end up.

Where is the fulcrum on a pair of scissors? Remember the lever turns on the fulcrum which remains in place. On double levers the fulcrum is where the two levers cross each other and are fastened together.

I forgot to take a picture of my scissors. You know what they look like, don’t you? These are double levers. Do you see where the fulcrum is?

Get a piece of cardboard and a pair of scissors. Where should you put the cardboard to cut it the easiest? Close to the fulcrum or far away?

Let’s review how a fulcrum increases force. Get a 200 page book and 2 pencils. Prop the book on the end of one pencil. Put the second pencil crosswise under the first pencil to act as a fulcrum. Try lifting the book with the second pencil away from the book and near the book. Which placement makes lifting the book the easiest?

Should the cardboard be near the fulcrum of the scissors or farther away? Double check by trying to snip the cardboard from both positions.

Pliers are a useful tool around the house. They can be used for gripping things or turning tight small lids. Do you see the two levers?

Another of the common double levers is a pair of pliers. Perhaps you have one to look at. Where is the fulcrum? Why are the handles for your hand to grip longer than the gripping ends of the levers?

Tin snips are used to cut sheet metal, flat plates of metal. The length of the handles can vary. As the handles get longer, will the snips part get more powerful?

On the farm I have another of the double levers. It’s called tin snips. These are used to cut sheets of metal such as metal roofing. If you don’t know anyone with a pair of these, you can look at the picture. Find the fulcrum. Like the pliers, one end of the levers is longer than the other.

Perhaps you can find some other double levers around your house. How do you recognize them?

What I Found Out:

The book lifted the easiest when the fulcrum pencil was close to the book. In the same way, putting the cardboard close to the fulcrum made cutting it much easier.

On both the pliers and the tin snips like with the scissors the fulcrum is where the two levers cross and has the bolt connecting the two.

Double levers are easy to recognize because they have two long pieces crossing each other and joined where they cross. That join is the fulcrum. Others I found included pruners for trimming plants, loppers for cutting brush and bolt cutters for cutting thick wires up to 1/2 inch thick.

Physics 11 Mass a Coin With Levers

Last Project we found out we could balance a heavy object with a light one by moving a lever over the fulcrum. Can we do this to mass a coin?

materials for project 11

Question: Can a lever be used to mass a coin?

Materials:

Piece of thin cardboard 3 cm x 28 cm

Dime

Balance

Metric ruler

Table

Procedure:

Mark a line 2 cm from one edge of the cardboard piece

Label the line R

The real purpose of the R line is to mark one end of the lever to tell the ends apart. It marks a good place to set the coin.

Place the cardboard piece on the edge of the table

Slide the piece over the edge of the table until it balances on the edge

As the cardboard lever moves out over the edge of the table, the end begins to rise. Take care it does not rise too far or the lever will slip to the floor.

Mark this point and draw a line across it

Label the line E

Measure the distance from line R to line E to the nearest mm

Mass the cardboard piece

Remember that a lever balances when the mass is equal on each side of the fulcrum.

Set the cardboard piece on the edge of the table

Set the dime centered on the line labeled R

Slide the cardboard piece over the edge until it balances on the edge

Mark this point and draw a line across it

Label this line 1

Measure the distance from the R side of the cardboard to line 1 in to the nearest mm

Mass the dime

Observations:

Mass of:

Cardboard:

Dime:

Distance:

R to E line:

Line 1:

Analysis:

Divide the line R distance by the line 1 distance for a mechanical advantage for the dime

Line 1 is where the lever balances with a dime on the R line. Go a millimeter too far and the dime slides down flipping the lever onto the floor.

Multiply this mechanical advantage by the mass of the cardboard to get a mass for the dime

Conclusions:

How important is balancing the cardboard to mass a coin?

How important is it to measure accurately?

Compare your calculated dime mass to your scale obtained mass.

Where is the fulcrum for your lever in this Project?

A lever has two arms. What were the two arms for the lever in this Project?

Do you think a lever is a good way to mass a coin? why do you think this?

What I Found Out:

Balancing a piece of cardboard on the edge of a table is harder than it sounds. I slid the cardboard piece out until it seemed balanced. When I moved toward my camera, it slid onto the floor. I started over again.

Since the distances are being measured to the millimeter and one of these is small, It’s important to get as close to the final balancing point as possible. Any breeze makes this impossible.

I used a regular ruler with centimeters and millimeters on one side and inches on the other. It helps that the 0 line for the centimeters is not on the edge of the ruler. This makes it easier to get an accurate starting place. If the 0 line was the edge of the ruler, I would have started on the 1 cm line and deducted the 1 from the reading. one reading did come out between two millimeter lines. I used the closest line for the distance.

It takes care to keep the lever perpendicular to the table edge. You have to tap it lightly in the center, not on a corner to move it slightly until it balances.

I again had the lever slide to the floor with the dime on it. When I balanced the lever, the line R distance was 9.5 cm and the line 1 distance was 18.5 cm. The mechanical advantage was 0.51. Multiplying this by 3.5 g gave a coin mass of 1.9 g for the dime. My dime had a mass of 2.3 g on the scale. The two masses were close.

The edge of the table was the fulcrum. The R line marked one arm of the lever. The E line marked the other arm of the lever.

I don’t think this is a very good way to mass a coin. Finding the true balancing point is difficult. A regular ruler is not very accurate for measuring. There are too many places where errors can creep in.

Physics 10 Exploring Levers

The Greek Archimedes once said that given a fulcrum and a lever, he could move the world. Levers are another simple machine. What is it and how does it work?

materials for physics project on levers

Question: How do levers work?

Materials:

Wood slat 40 cm long by 5 cm wide

Triangular or 1” wood block [I found the 1” block works best.]

Several weights, 2 the same, 1 heavier, 1 lighter

Scale

Ruler

Pencil

Procedure:

Place the block on a table

Note: This is your fulcrum.

The slat is not exactly level. This shows as my measurement of each end gave two slightly different values.

Place the wood slat on the block moving it back and forth until it balances

Note: The slat is your lever

Mark the balancing point

Measure from the end of the slat to the line from both ends

Mass your weights unless they are from a weight set so you know the masses

Keeping the balancing point over the fulcrum, place a mass at one end of the slat

Placing a mass on one end causes that end to drop to the table while the other end rises.

Observe what the lever does

Place the identical weights, one at each end

Adjust the slat until it is again in balance

Take one weight off

Place the light weight on the other end of the slat

A teeter totter on a playground behaves this way when a heavier person sits down on one end. How can this person make it balance so both people have fun?

Move the slat back and forth until it balances

Measure the distance from the balance point over the fulcrum to each weight

Remove the weights

Return the slat to the original balancing line

Place the heaviest weight on one end of the slat and a lighter weight on the other end

Predict how you will need to move the slat to balance the two masses

Move the slat until the two are in balance

Observations:

Mass of weights

Distances:

From ends to balancing line

From masses to balancing line

Same mass weights

Mass and light mass

Mass and heavy mass

Describe what happens:

When you balance the slat

When one mass is put on one end of the slat

When the two identical weights are on the slat

When the light weight is put on one end

When the light weight is balanced

When the heavy weight is put on the slat

Prediction of where the slat will balance

When the heavy weight is balanced

Analysis:

Multiply the mass times the distance for the two identical masses

Multiply the mass and distance for the mass and the light mass

If you consider the formula of Fd = Fd it explains why a heavy mass is at a short distance to balance with a light mass.

Multiply the mass and distance for the mass and the heavy mass

Conclusions:

Compare the lengths when the salt is balanced.

If you could mass each end of the slat, how do you think these would compare?

Draw the lever, fulcrum and one mass

Put arrows to show where the forces are acting on the lever system

The mass exerts mass downward on one end of the lever. That puts an equal upward force under the other end. The force vectors are equal and opposite so the center, on the fulcrum, has no net force acting on it.

Why does the slat balance at the same place when two equal masses are balanced?

How does the mass x distance results compare for the two identical masses?

How do these results compare for the light weight and the heavy weight?

A rule for levers is that the force times the distance for one arm or side equals the force times the distance for the other arm or side. Do you think this is correct? Why do you think this?

How can this be used to move a heavy object?

What I Found Out:

I tried using a triangular fulcrum. The slat would balance on the edge but it was very difficult to do this. It worked much better to use the 1” board piece as a fulcrum. I did have to watch that the slat was level as it would balance a little before it was really level.

I was in a hurry. I hope you take your time. My lever is not quite balanced between the 20 g and 50 g masses. You can tell because the slat is not level.

When I balanced the slat on its own, the ends measured 37.0 cm and 38.7 cm. This was nearly equal. The two ends would have the same mass as the slat would be divided in half.

The mass pushes down on the lever so it sinks to the table top. That means a force is pushing up the other end.

When I put masses of equal mass on the ends of the slat, the force pushing on each end was the same, the total mass of each end remained the same so it would balance at the same place as it did without the masses.

The balancing point puts equal mass on each side of the fulcrum. since the masses are equal, the rest of the set up is equal.

My two equal masses gave 740 g-cm and 772 g-cm. When I looked at the pictures of this, the slat wasn’t completely level so the two were probably even closer in size.

When I balanced the lighter mass, the slat moved the heavier mass closer to the fulcrum. The distances were 30.0 cm for the 50 g mass and 43.0 cm for the lighter20 g one. This gave the Fd values as 150 g-cm and 91.2 g-cm. The distances for the 500 g mass was 13.0 cm and 62.6 cm for the 50 g mass. The Fd values were 6500 g-cm and 3030 g-cm.

The Fd values for my experiment weren’t very close. This is the rule a lever normally follows so I need to look over my Procedure and Observations more closely.

The idea of a simple machine is to do the same amount of work using less effort. A lever would do this if the distance to the heavy object was short and the distance to where the force is applied is long. A long distance times a small effort will equal and larger effort over a short distance.

Physics 9 Simple Machine Called Wedge

Perhaps you have learned to sew on a button. Take a close look at the sewing needle. One end is a point. The needle gets thicker the farther up the needle you go. This is one kind of wedge.

A yarn needle for sewing with yarn is large so it’s easy to see the pointed end and how the needle thickens going away from that end.

Find a door stop, one of the brown rubber kind that is pushed under a door to keep it open. Look at it from the side. It has a point and gets thicker farther from the point. this is another kind of wedge.

Maybe you know someone who carves wood. Ask to see a flat chisel. Look at it closely top and from the side. It starts at a broad point and gets thicker as you go away from the point. A chisel is a wedge.

Look at a wood chisel. Is it a wedge?

Question: How does a wedge work?

Materials:

Sewing needle

Piece of cloth

Procedure:

Look at the piece of cloth observing the thread pattern

Hold the piece of cloth

Push the needle through the cloth

Observe what the cloth does

Observations:

Describe and draw part of the piece of cloth

Describe how the cloth threads change as you push the needle through

From the side it’s easy to see a wood chisel has a point at the end the slopes up from there.

Special Section on Wedges:

Look at the pictures of a splitting maul. Does it look like the other wedges? Why do you think so?

A splitting maul has a typical wedge shape. The end comes to a broad point. The maul gets thicker going away from the point. Unlike the chisel this wedge goes out in two directions. The needle goes out evenly all around. All have a point.

Splitting mauls are used to split firewood. Usually the maul is swung down so the head hits the piece of wood. This is repeated as the crack in the wood widens until the piece splits into two pieces.

For this I used the maul as though it did not have a handle to show how the maul splits the wood. First I tapped the maul until it stood up in a piece of wood.

wedge point focuses force from the wedge

Even tapping the splitting maul enough so it will stand up creates a crack in the piece of wood.

Then I hit the top of the maul with a sledge hammer. This applies force to the top of the maul. Where does this force go?

The maul goes down into the piece of wood so some of the force pushes the maul downward.

The crack in the wood gets wider. Does some of the force go sideways? Why do you think so?

As the splitting maul goes further into the wood, the split gets wider. This crack follows the grain in the wood going to the center of the piece then splitting into two paths.

Conclusions:

When you push on a needle, you are applying force. Where does that force go?

How is a wedge like an inclined plane?

How is a wedge different from an inclined plane?

What I Found Out:

My piece of cloth had threads running up and down and other threads going across. The threads went over and under each other. They were tight so the threads did not shift.

When I pushed the needle through the cloth, the point went through between the threads and pushed them apart. After the needle went through the cloth, the threads tried to go back into place but left a small hole where the needle had been.

The splitting maul has a broad point and gets thicker going away from the point. It is a wedge.

The force goes into the maul. Part of the force goes down and pushes the maul further into the wood.

Part of the force pushes the wood apart. There must be force pushing the wood apart. The only place any force is being applied is on the top of the maul. Some of it pushed the wood apart.

An inclined plane has a broad point at one end and gets thicker going away from that point.

An inclined plane sits still. Objects are pushed or pulled up the ramp.

Force is applied to a wedge. That force pushed the wedge forward and pushes outwards to push things apart.

Physics 8 Exploring How Screws work

What do a pencil sharpener, a screw, a scissor jack and an inclined plane have in common? Find yourself several different kinds of screws and take a look.

Common screws have one of two heads. The top one is a straight slot and takes a regular screwdriver. The bottom one has a cross slot and takes a Philips screwdriver.

Note: The raised metal going around a screw is called a thread. The top is called the head. Some screws have slots on their heads and take straight screwdrivers. Some have crossing slots and require a Philip’s screwdriver.

materials for project 8

Question: How do screws work?

Material:

Several different screws, same diameter but different threads

Screwdrivers for the screws

Block of wood with drilled holes the size of the screws in it

Ruler

Procedure:

Examine one of the screws closely to see how the threads are arranged

Hold a screw between your finger and thumb turning it with the other hand

The screw turns into the wood a tiny bit then the head cuts into my fingers as I try to turn it a little more and can’t make it budge.

Put the end of the screw in a hole in the board and try to turn the screw several turns using your fingers then use a screwdriver.

Take that screw out of the hole

Find two screws with different threads, one with threads far apart and one with threads close together

Start these two screws in the board until they stand up by themselves

The head is shaped like a wood screw’s head so this screw is used for wood. Fine threads are often used for fine work such as furniture.

Measure the height of the two screws

Turn each screw two complete revolutions

This was the longest screw as well as the one with the finest threads. If you measure from one thread down two, this should be the same as the amount turning the screw twice will put it into the wood. For this screw that was 0.2 cm.

Measure the height of the two screws

Observations:

How are the threads arranged on the screw?

How does it feel to turn a screw with your fingers?

How does it feel to turn a screw into the wood?

How it feels to turn a screw with a screwdriver

This is a wood screw with definite threads not too far apart but not real close together either. The top will fit into the wood so it won’t catch on anything rubbed over the wood later.

Height of the screws:

Wide thread

beginning

ending

At first glance this screw went in the farthest but it was the shortest so it really only went in 0.4 cm in two full turns.

Narrow thread

beginning

ending

Conclusions:

If you could unwrap the threads on a screw, what simple machine would they become? Why do you think so?

Why do we use a screwdriver to put in a screw?

Compare how fast a screw with wide threads goes in to one with narrow threads.

Looking at the three screws it is easy to see the right one has fine threads and the left on has coarse threads. The middle one is in between the other two.

What I Found Out

I had three screws. One had coarse threads. One had fine threads. One was in between.

When I held a screw and turned it, it crawled up between my fingers. It felt like my fingers were sliding up the threads.

Of course I can’t really take the threads off. But if I could, the thread would become a slanted line and be like an inclined plane from the bottom to the top of the screw. I think that because the thread is a continuous line going up the shaft.

This is a deck screw. It has widely spaced threads to make it easy to put it into coarse wood. The top is angled to fit into the wood smoothly so the deck surface will be smooth.

Trying to put a screw into a hole in the wood using fingers does not work. The very tip will go in but then the fingers can’t turn it anymore. A screwdriver gives more power to my hand and makes the threads go into the wood.

After two full turns the coarsely threaded screw was only 1.5 cm high. It went in 0.6 cm.

My screw with fine threads started at 2.6 cm and ended at 2.3 cm so it went in .3 cm. The medium threads started at 1.7 cm and ended at 1.3 cm going in .4 cm. The coarse threads started at 2.1 cm and ended at 1.5 cm going in .6 cm.

Coarse threads go in much faster than fine threads.

Physics 7 Mechanical Advantage

The reason for using a simple or complex machine to do work is to use less effort or force to do the same amount of work. How much force a machine will save is its mechanical advantage.

materials for physics 7

Question: What is the mechanical advantage of an inclined plane?

Materials:

2 boards, one twice as long as the other

stack of thick books, at least four 5 cm or more thick

spring scales

Procedure:

Set up the stack of four books

Measure the height of two, three and four book stacks

Lift your block using the spring scale to the top of the stack

The blocks are being lifted to the top of the book pile. No matter how the blocks get there, this is the work being done. Lifting a heavy weight is easier using a ramp. Mechanical advantage determines how well the ramp works.

Record the force needed

Measure the length of the two boards

Set up one board as an inclined plane to the top of the stack of four books