SCIENCE - GRADE 5 Monday, May 18 – Friday, May 22

PURPOSE

Grade Level Expectation: 5-PS2-1 (New Material) I can support an argument that the gravitational force exerted by Earth on objects is directed down.

WATCH

Monday: In Your World: Analyze this photo gallery. What do you notice about the birds? How are they remaining in the air? Is gravity different on birds than other animals and objects? Tuesday: Watch this video, Good Thinking!—Falling 101, to learn more about gravity and how matter, mass, and air resistance impact the gravitational force on objects. For a screen free option, read the Gravity Fact Sheet. Wednesday: Watch this video, Gravity & Inertia to learn more about the center of gravity, inertia, and how more or less mass affects the gravitational force on objects. For a screen free option, read the Gravity Fact Sheet. Thursday: Watch this video, Gravity 2: Air Resistance, to learn more about air resistance on objects of varying weights.

PRACTICE

The following activities provide opportunities for students to practice their learning.

Monday: Watch this video to learn more about the Center of Gravity. For practice, try finding the center of gravity with three objects at home. Do this by balancing it on your finger or another object. When an object is balanced, you have found the center of gravity. Using your observations how might this relate to a bird’s flight? Tuesday- Complete Galileo’s Balloon Investigation. Using your observations from the investigation, support the provided claim with evidence and reasoning. You may refer to the Gravity Fact Sheet and Tuesday discussion questions for additional support. Wednesday- Following the video, you may practice your science knowledge with the online quiz. Click here for a screen free practice quiz. How do these activities help you to understand a bird’s flight? Thursday: Complete this Falling for Gravity Investigation. Using your observations from the investigation and knowledge of science, support the provided claim with evidence and reasoning. You may refer to the Gravity Fact Sheet and Thursday discussion questions for additional support.

DISCUSS

Monday: How can a bird remain in the air for long periods of time? Why wouldn’t the gravitational force on birds pull it to Earth? Tuesday: Does mass or air resistance change the gravitational force on objects? Explain. What observations in the investigation helped you to determine the effects of mass and air resistance on gravitational force? How long did it take each item to fall? Why did this happen? Can you apply your new learning to explain how the gravitational force on birds? Wednesday: If you were to explain the gravitational force of a pencil and a table to your friend, what could you say about their attraction? Why does this happen? Be sure to discuss mass when explaining. Thursday: Does one marble win the race, or is it a tie? Do you receive the same results for each race? Is air resistance a factor? Is mass a factor?

PRODUCT

Friday

Support an argument that the gravitational force exerted by Earth on objects is directed down. Read and analyze How Birds Fly: An In-Depth Journey North Lesson by website or screen free option. Review concepts learned this week. Respond to the prompt using a CER format.

C – Claim: State a claim to explain how the gravitational force exerted by Earth on birds is directed down even though birds can remain in the air for extended amounts of time. E – Evidence: Cite evidence from this week’s learning to support your claim. R – Reasoning: Apply your knowledge of science to explain your evidence.

Screen free opportunities Monday through Wednesday in the Watch Section. • Bird Photo Gallery Screen Free • Gravity Fact Sheet Activities Screen free opportunities Monday through Thursday in the Practice Section. • Center of Gravity in Home Objects • “Galileo’s Balloon Investigation” • Gravity & Inertia Practice Quiz • “Falling for Gravity Investigation” Screen free opportunities on Friday in the Product Section. • How Birds Fly: An In-Depth Journey North Lesson and CER prompt

Photo Gallery

Gravity Fact Sheet

Gravity Fact Sheet Gravity is the pull from Earth that keeps objects from floating into space. Gravitational Force is the attraction between any two objects. Any two objects attract each other with equal gravitational force. Force can cause an object to change direction.

Mass is the weight of an object. The more mass an object has, the harder it is to move. The less mass an object has, the easier it is to move. Objects with less mass are pulled toward Earth by gravity because they are smaller and have much less mass than Earth. These objects feel the force more. Take a basketball for example. It has a much smaller mass than Earth, so the gravitational force pulls it towards Earth. Smaller objects are pulled toward the larger object. The moon, on the other hand, has much more mass. The moon still feels an equal gravitational force from Earth, but it is not pulled to the ground because it is so large. This means that all objects have equal gravitational force, but smaller objects are pulled to Earth because they are easier to move. Many believe that heavier objects fall faster than lighter objects. This is not true. Objects dropped of varying mass from the same height will hit the ground at the same time as long as the objects are not affected by air resistance.

Air Resistance—If air has the ability to pass through objects as it falls, it will slow the object in its fall. For example, a piece of paper or feather has the ability to let air slow its fall. The object hits the ground later than other objects, not because of the gravitational pull, but rather because of the effect of air resistance.

Gravitational force pulls from each object’s center of gravity—The exact center of an object’s mass is its center of gravity. Think of balance. When an object is balanced in a particular place, you have found its center of gravity. Try finding the center of gravity of a pencil using your finger. Lay the pencil long ways over the tip of your finger. Adjust the pencil until it can balance on your finger. When you can balance the pencil on your finger, your finger is touching the pencil’s center of gravity. Different objects have different centers of gravity.

Galileo’s Balloon Investigation Adapted from Turtlediary.com

The purpose of this experiment is to observe Earth’s gravitational force on objects of different weights. At the end of this experiment, you will need to use your observations to justify this claim:

Earth’s gravitational pull exerts its force on objects pulling them straight down toward Earth.

Materials: For this activity, you will need a sturdy chair, stopwatch, balloon, household items.

Directions: 1. Gather household items of different weights and sizes. (i.e. ball, action figure, doll, balloon, etc.) 2. Stand on a chair and drop each item one at a time from the same height. 3. Record/Observe how long it takes each item to reach the ground.

How long did it take each item to hit the ground?

Many believe heavier items hit the ground first. However, this is not true. The rate of Earth’s gravitational pull on all objects is the same no matter their weight. Given the absence of air resistance, each object should reach the floor at the same time. Items that experience air resistance land later. Do your findings support this? How is this different from last week’s paper investigation? What impact did air resistance play?

TASK: Using your observations, support the following claim with evidence. C – Claim: Earth’s gravitational pull exerts its force on objects pulling them straight down toward Earth. E – Evidence: Cite evidence from the investigation to support your claim. R – Reasoning: Apply your knowledge of science to explain your evidence.

______Gravity & Inertia Practice Quiz Adapted from StudyJams.Scholastic.com

1. Which of these can cause a moving object to change direction? a. Inertia b. Velocity c. Force d. Mass 2. What is gravitational force? a. the force that keeps people from moving b. the force of attraction between any two objects c. the force that makes inert objects start moving d. the only force that changes an object’s velocity 3. Where is an object’s center of gravity? a. the exact center of its mass b. the part that is closest to the Earth c. any part of an object, as long as it has mass d. all of the above 4. A paperclip and a computer are sitting on your desk. What is true about the gravitational force of these two objects? a. The paperclip attracts the computer with less gravitational force than the computer attracts the paperclip. b. The computer and the paperclip attract each other with equal gravitational force. c. The computer attracts the paperclip with less gravitational force than the paperclip attracts the computer. d. There is no gravitational force between the computer and the paperclip. 5. Why don’t we see the ground coming toward us? a. We have less gravitational force than the Earth. b. We have more inertia than the Earth. c. We have less mass than the Earth. d. We are already standing on the Earth. 6. Why doesn’t the moon crash toward the Earth’s surface? a. It has very little inertia, so it stays in the sky and floats through space. b. It has a lot of mass, so it feels the Earth’s gravitational force less than smaller objects do. c. It has more mass than the Earth, so it stays in one place while the Earth orbits it. d. It is too small to fall through Earth’s atmosphere and reach the Earth’s surface. 7. Why is it impossible to “defy gravity”? a. There is no gravity. b. You can’t defy gravity without going to another planet. c. Gravitational force exists every place where there are two objects.

d. Nothing has enough force to resist gravity.

7.C 6.B; 5.C; 4.B; 3.A; 2.B; 1.C; Answers: Falling for Gravity ScienceNetLinks Gravity is the force that pulls on every object on earth. Have you ever wondered if the pull is always the same for every single thing? If you drop a penny and a pen from the same height, they'll hit the ground at the same time, too. But if you drop a pen and a piece of paper, the paper school may drift and take a lot longer to fall than the pen does.

Can you guess why?

Let's test gravity!

Here's all you a desk or table need: a ruler or pencil

different-sized marbles binder, notebook, or books small table

Here's what to do:

1. First make a ramp. You can use a binder notebook, or tilt a small desk or table by putting books under two of the legs. Make sure the ramp is tilted just a little bit, so the marbles will roll slowly -- then you'll be able to watch them better. The smoother the surface, the better it is! 2. Take two marbles, a big one and a small one. Line them up evenly at the top of the ramp. 3. Use a ruler or meter stick as a gate. If you don't have a ruler or meter stick, use anything that is straight, like a pencil or a rolled up piece of paper. Hold the starting gate and lift it quickly so that both marbles start to roll at the same time. 4. Watch the finish line closely to see if one marble comes in first or if it's a tie. Keep a sharp eye out to see if there is a winner! 5. Do the race at least 3 or 4 times to check for accuracy. It doesn't hurt to try it even more times than that!

Does one marble win the race, or is it a tie?

Are the results the same for every race?

Here's more about gravity:

Have you ever noticed the force of a magnet? If you put two magnets next to each other, they will either push or pull on one another. The push or pull is the force of magnetism. Gravity is a force, too. It makes all things attract each other. The bigger the object, the stronger the force is. The gravity of earth has a really strong pull, because earth is such a big planet. That's why things fall to the ground instead of floating around. It might seem strange, but objects that weigh a lot fall at the same speed as objects that weigh just a little.

ScienceNetLinks ADVANCING SCIENCE, SERVING SOCIETY

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How Birds Fly

An In-Depth Journey North Lesson

This six-part lesson is designed to teach you the basics of how birds fly.

Introduction Birds have beautiful feathers and lovely songs that bring joy and wonder to us humans. And flight is the feature that probably captures the human imagination more than anything else. For millennia, people have watched birds in the sky and wished we could fly, too.

There are almost as many ways of flying as there are kinds of birds. Albatrosses glide and soar with long narrow wings stretched out, sometimes staying aloft for hours without a single wing beat. Hummingbirds, on the other hand, can't rest their wings for even a second in flight. Woodpeckers have a swooping flight, crows fly in a straight line, and swallows dart and weave every which way.

The Gravity of the Situation Isaac Newton is the scientist who first realized that gravity is a force between two objects that draws them toward each other. The more mass an object has, the more it pulls other things toward it. The largest object anywhere on earth is the planet itself, so gravity pulls everything down toward the center of the earth.

Question 1: If gravity pulls everything down, why do helium balloons go up? Gravity pulls on birds, too. In order to minimize the effects of gravity, birds are adapted to be as light as possible. These are some adaptations that help make birds light:

• Hollow bones • Feathers

• Babies don't grow and develop inside the mothers' bodies. They develop in eggs outside their mothers' bodies. Bird skeleton: • Birds eat foods that are very high in usable calories so designed for flight they get as many calories as possible from from a small amount of food. Seeds, fruits, and meat (from prey) are the main food items for birds. Virtually no birds (except the Hoatzin, which lives in South America) eat leaves, which take a long time to digest. Their efficient digestion allows birds to get rid of useless weight very quickly. • Birds don't have bladders. A bird urinates as soon as it has to, getting rid of the useless weight.

Winging It Birds are not the only animals that fly. A huge number of insects fly and so do a few vertebrates. Flying fish and flying squirrels can take off and glide through the air for fairly long distances, and bats are very well adapted for genuine flight. But there are not nearly as many kinds of bats in the world as there are birds.

Question 2: Why might bird wings be more adaptable to flight than bat wings?

A bird's breastbone, or sternum, is shaped like a keel to attach the powerful wing muscles. The bones of a bird's wings are surprisingly small compared to the size of the wing. All the bones and muscles of the wing are in the front and covered with feathers that protect and streamline the wing. The actual flight feathers are attached to the wing within little pits in the bones. Bird wing bones

Designed for Flight Bird wings are not the only part of their bodies designed for flight. Just about every part of a bird body is specially adapted to help the bird fly. A bird's center of gravity is the balance point between its two wings and between its head and tail. If it were possible to perfectly support a bird right at its center of gravity without it squirming around, the bird wouldn't tip in any direction. To fly well, birds must have most of their weight in their center of gravity, and very little weight in front of or behind Whooping Cranes it. Their bodies have many special adaptations to help are "designed" for accomplish this. A few are described here: flying • Birds don't have teeth or a nose, which are heavy and would be too far forward. To grind their food, their stomachs have a gizzard near their center of gravity. They use their mouth and the nostrils located on the top of their lightweight beak to breathe. (Their nostrils are also used for smelling. Older bird books say most birds can't smell, but current research proves that many birds have at least some sense of smell.) • Their tail and wing bones are very short, attached to sometimes long (but always very light) feathers. • Bird lungs don't fill up with a lot of air like ours do. All vertebrate lungs (including birds') need to be placed near the heart. Our huge, lightweight lungs set in our chest work fine for us, but birds need their heaviest organs in their chests. So their lungs, which can hold very little air, are flat and sit against their back ribs. The air birds' breathe in flows through the lungs into big balloon-like air sacs that fill much of their lower abdomen, behind their center of gravity. When they breathe out, the air flows back through the lungs through different passages. Their lungs are VERY efficient at pulling out oxygen (which they need in great quantity) as streams of air go in and out.

Question 3: Many people confuse herons and cranes. Watch how they Crane vs. Heron Flight fly and you will see clues: Herons pull their neck into a crook while they fly. Cranes fly with their neck outstretched. Why do you think these two bird families fly in different ways? HINT: think about the different foods they eat and how they catch them, and don't forget their center of gravity! Cranes fly with neck Herons fly with neck in outstretched a crook Photo Dr. Glenn Olsen Photo Brian Small An Aerodynamics Primer In order to fly, birds must do four things:

1. get up in the air 2. stay up there as long as they need to 3. move in the direction they want to go 4. come back down safely

Their wings help them to accomplish all of these jobs. Let's look at each job:

1. Getting up in the air Birds have many different ways of taking off. Some, like loons, run into the wind, and the rush of air beneath their wings lifts them up. Others, like puffins and Peregrine Falcons, jump off cliffs and other high perches. Chimney Swifts simply let go of their chimney or other vertical perch, and fall into the air.

Hummingbird wingbeats are so powerful that they can go straight up from a perched position without jumping. Songbirds, Whooping cranes cranes, and many other species leap up on strong legs while taking off. flapping their wings, and there they go.

We humans could try leaping and flapping our arms, or running into a stiff wind, but we wouldn't get very far off the ground! The reason birds can is because of the special shape of their wings. The bones of bird wing are in front, covered with a smooth layer of feathers that taper toward the back. The back of the wing is just a single layer of flight feathers. People who study As the airfoil moves aerodynamics say a wing has this shape to serve as an airfoil. to the right, the air When air comes straight toward an airfoil (from facing directly into above it, going a the wind or running fast into the air) the special shape causes the longer distance, air to flow faster on top of the wing than under it. The faster air must travel faster above lowers the pressure (sort of sucking the bird up) while the than the air below it. slower air below raises the pressure (pushing the bird up). These This makes the forces raising the bird are called LIFT, which makes the bird go pressure above up! lower than the Try This! pressure below, To see how an airfoil works, hold a creating lift. narrow strip of paper near your mouth and blow across the top. The air moves faster above than below, and the paper will rise. Does this work with a larger piece of paper? Why or why not?

2. Staying up there

Once birds get up in the air, they use two main flying techniques to stay up there.

Soaring: When birds soar, they take advantage air currents to help hold them up. Three kinds of air currents are especially helpful to soaring birds.

• Thermal air currents develop in places where the air is warmer in one spot than an adjoining area, such as a paved road alongside a snowy field. Even on a very cold day, the sun will heat the pavement at least a few degrees more than the snow. This slightly warmer air is slightly lighter than the colder air, and rises. This rising air current can lift very light objects, like feathers and hollow bones. The birds that most often take advantage of thermals (like the hawks that fly along coastlines) usually have very wide wings and tail. This makes the area of their wings very large compared to their body weight. • Updrafts, also called obstruction currents, develop when wind hits an obstruction, like a cliff or a building. The rushing air has to go somewhere, so it goes up, and can carry a bird up with it. Birds who fly on updrafts (like the many hawks that migrate along Hawk Mountain, Pennsylvania) also have very wide wings and tail. • Wind moving toward a bird with spread wings can hold the bird up, thanks to the airfoil shape of the wings (see airfoil illustration above). Birds that fly on moving air currents often have long, narrow wings, such as gulls and albatrosses.

Flapping: When birds flap, the stroke of their downbeat moves the wing tips forward and downward. The wingtips make a loop at the bottom of the downstroke, and as the wings move up, the wing tips move upward and backward. In the downstroke, the pressure is higher below the wing than above, causing lift. And as they move forward, the rush of air on their airfoil wings

causes more lift. But because flapping birds have smaller wings than soaring birds, they must move forward faster to stay in the air. Most songbirds must fly at least 11 miles per hour to stay Photo Operation up. One scientist calculated that for an ostrich to stay aloft, it Migration would have to take off and maintain a minimum speed of 100 miles per hour. Birds who use their wings to flap more than soar often have smaller wings than soaring birds.

3. Heading in the right direction

Soaring birds take advantage of thermals and updrafts by flying in a circle. The rising air carries them higher and higher in a spiral. They couldn't simply hold still and go straight up because without moving forward on their airfoil wings, they would simply drop to the ground. But the problem with circling is they don't go in any special When a hawk flies from left direction. So when migrating birds soar on a thermal, they to right, it spirals up on one rise as high as the thermal will carry them with their wings thermal and then glides spread, and then they pull back the wings into a more downward toward the next narrow point and glide in the direction they want to move. thermal. Gliding birds move exactly the way paper airplanes do, slowly losing altitude. So as migrating birds glide, they seek out another thermal to gain altitude again.

Soaring birds that wish to stay aloft without flapping in normal wind usually fly INTO the wind for lift. But that same wind that holds them up slows their forward movements. In order to get somewhere, soaring birds make delicate adjustments to turn slightly now and then. They gain lift for a while and then lose altitude as they head where they actually want, and then gain lift again. This is why gulls usually fly in a more zig-zaggy pattern than many other birds.

Like soaring birds, flapping birds have their easiest time staying up when they're facing the wind, but their easiest time moving forward when being pushed by the wind. Since their forward momentum and the lift they get from flapping is more important than the lift they get from the wind or air currents, they can get where they want to if they just point themselves in the right direction and go!

4. Coming down safely Many birds, like chickadees and robins, can fly fast until the last seconds and still land easily and safely. To slow down quickly, they change the angle of their wing to be higher and higher, increasing drag (to slow their forward movement) and decreasing lift (to help them move downward). Some birds need to slow down for a longer time in order to make a safe landing. Many ducks, geese, and cranes use their outstretched feet as well as their open wings to increase drag, acting as brakes to slow Photo Richard van them. Heuvelen, Operation Migration When airplanes are in the sky, pilots tuck in the landing gear so it doesn't slow them down. Most birds do the same thing; they tuck their feet and legs beneath their tummy feathers. Birds with very long legs or legs too far back on their bodies don't normally tuck in their legs.

Question 4: What are some kinds of birds that don't tuck their legs in as they fly?

Putting It All Together: How Cranes Fly

Cranes have large wings, a long neck, and long legs. They fly with their legs stretched out behind and their neck stretched out ahead, balancing each other so their center of gravity is between their wings (where it needs to be for long flights). Their long, wide wings allow them to fly using different kinds of flight techniques.

When cranes are flying just a few miles or less, they use typical flapping flight. They usually flap with steady beats until they come in for a landing. Then they use their legs and wings to slow down and ease their way to the ground. When cranes are flying long distances, especially on migration, they often soar on thermals until they reach a great altitude, and then use a combination of gliding/soaring and flapping to cover the longest distance using the smallest amount of energy.

Cranes can bend their legs and draw their feet in to their bodies when it's severely cold during migration, but that's exceptional. Try This! See if you can design a crane that can really fly, or at least glide. Use cardboard, paper, paste or glue, paper clips, and any other materials you want to try. If you want a pattern designed from a real crane silhouette, click on the small pattern to see a larger sized one. Or try to develop your own pattern, from paper airplane designs or anything else that might work. Test your birds to see which stay aloft the longest, and which fly the farthest.

This silhouette was drawn from a real National Science Education Standards crane. But can it fly? Life Science

• Each plant or animal has different structures that serve different functions in growth, survival, reproduction. • Living systems at all levels of organization demonstrate the complementary nature of structure and function.

Physical Science

• Objects have observable properties, including size, weight, shape, color, temperature, and the ability to react with other substances. • If more than one force acts on an object along a straight line, then the forces will reinforce or cancel one another, depending on their direction and magnitude.