Use feeder observations and an Earth model to argue about gravity.
Answer Key
1. Compare the feeder trials
Read the report and trial records. Use the observations to answer the questions.
A Bird Feeder Comparison
Imani and Rafael study two bird feeders in Imani's backyard. The north feeder is attached to a tall post near the garden wall. The south feeder is attached to a post near the patio. The platforms are at the same height above level ground. The students want to compare what happens when objects are released near each feeder.
For each trial, a student holds an object 90 centimeters above the feeder platform and releases it without a push. The other student watches the object's first motion and where it lands. They test a wooden bead and a crumpled paper ball. They use the same release height and repeat each kind of trial five times at each feeder. A light breeze is not blowing during the trials.
At the north feeder, all five wooden beads first moved toward the platform, and all five paper balls did the same. At the south feeder, all five wooden beads first moved toward the platform, and all five paper balls did the same. When Rafael gave one bead a gentle push toward the yard, the bead moved toward the yard and also moved toward the platform.
The students make a paper model of Earth. They mark the center with O and mark two places far apart on the outside of the model, a north mark near the top of the paper and a south mark near the bottom. On the model, an arrow for Earth's gravity starts at a place on the outside and points toward O. The arrow at one place may point in a different page direction from the arrow at another place.
Feeder trial records Location | Object | Trials | First motion observed North feeder | wooden bead | 5 | toward the platform North feeder | crumpled paper ball | 5 | toward the platform South feeder | wooden bead | 5 | toward the platform South feeder | crumpled paper ball | 5 | toward the platform
1.
Which claim is best supported by the release trials?
○A.Objects move toward the north feeder because it is higher on the page.
●B.Released objects at both feeders first moved toward the nearby platform.
○C.Paper objects move toward a platform, but wooden objects move away.
○D.Objects move toward whichever feeder has more birds nearby.
2.
Select the TWO observations that directly show the first direction of released objects.
All five wooden beads at the north feeder first moved toward the platform.The students marked the center of the paper Earth model with O.All five paper balls at the south feeder first moved toward the platform.The two feeder platforms were at the same height above level ground.
3.
Which plan would make the fairest comparison of a third feeder location with the two locations in the records?
○A.Use a different object and release it from a height chosen at that feeder.
●B.Use the wooden bead at the same height, with no push, and repeat the trials.
○C.Release several objects at different heights while a fan blows.
○D.Ask a student to point toward the third feeder before each release.
4.
Select the TWO observations that show the tested material did not change the first direction at a given feeder.
At the north feeder, both the wooden bead and paper ball moved toward the platform.The platforms were 90 centimeters below the release points.At the south feeder, both the wooden bead and paper ball moved toward the platform.The students worked in a backyard with two feeder posts.
5.
Across the four sets of trials, how many releases first moved toward a feeder platform?
○A.5 releases
○B.10 releases
○C.15 releases
●D.20 releases
2. Reason from the evidence
Use the observations and the model description. Separate what the students observed from what the model helps explain.
6.
What comparison is supported by the records?
○A.The paper balls had a stronger pull than the wooden beads.
●B.The first downward direction was observed for both tested materials at both feeders.
○C.The south feeder had a different kind of gravity from the north feeder.
○D.The wooden beads reached the platforms faster than the paper balls.
7.
Sort each statement by whether the feeder records provide enough evidence to support it.
Both tested objects first moved toward the platform at the north feeder.The wooden bead and paper ball took the same amount of time to land.The same first direction was observed at the north and south feeders.Gravity pulls with greater strength at the south feeder.
Supported by the records
Not established by the records
Both tested objects first moved toward the platform at the north feeder.
The same first direction was observed at the north and south feeders.
The wooden bead and paper ball took the same amount of time to land.
Gravity pulls with greater strength at the south feeder.
8.
Rafael says, “Down must mean toward the bottom edge of our paper.” Which response best uses the Earth model?
●A.The model shows that down points from each place toward Earth's center.
○B.The model shows that down points toward the north feeder on the page.
○C.The model shows that down points toward the south feeder on the page.
○D.The model shows that down changes when the object is made of paper.
9.
What does the bead's motion after the gentle yardward push show?
○A.A sideways push can remove the downward pull for a short time.
○B.A bead moves toward the yard instead of toward the platform.
●C.An object can move sideways while its motion toward the platform continues.
○D.Gravity pulls objects in the direction of a person's push.
10.
Select the TWO statements that correctly connect the feeder evidence with the Earth model.
The trials show first motion toward local platforms, and the model shows a pull toward Earth's center.Because both feeders are on one page, their gravity arrows should point in the same page direction.The two feeder locations provide observations that can be compared with center-directed arrows.The model proves that the paper ball has a different pull from the wooden bead.
11.
On the paper Earth model, the north mark is above O and the south mark is below O. Which pair of arrows best represents gravity at those two marks?
○A.Both arrows point upward, away from O.
○B.Both arrows point downward on the page, toward the lower edge.
●C.The north arrow points toward O, and the south arrow points toward O.
○D.The north arrow points sideways, and the south arrow points upward.
12.
Which statement carefully describes what the trials do and do not show?
●A.They show first direction at two feeder locations, while the model extends the idea to Earth's center.
○B.They show that objects fall through Earth toward O after leaving a feeder.
○C.They show that the page's lower edge is the source of the pull.
○D.They show that a gentle sideways push changes the direction of gravity.
3. Build the argument
Use the evidence to complete the model connection and write a scientific argument.
13.
Word bank: center · edge · sky
On the Earth model, a gravity arrow from the south mark points toward the model's center. Write one word from the word bank: center, edge, or sky.
14.
Argue for this claim: Earth's gravity pulls objects down toward the center of Earth. Use one observation from the north feeder, one observation from the south feeder, and the Earth model. Explain why “down” can point in different page directions at different places on Earth.
At the north feeder, all five wooden beads and all five paper balls first moved toward the platform. At the south feeder, both kinds of objects also first moved toward the platform. These observations show a repeated local downward direction at two places. The Earth model shows gravity arrows from both places pointing inward toward Earth's center, so down is not one fixed direction on a page. It can point in different page directions while still pointing toward the center of Earth.