Gravity and Motion in Space Activity: 8 Hands-On Stations for Teaching Mass, Weight, and Orbital Motion (TEKS 7.9B)

Chris Kesler · 8 min read

Why doesn't the Moon fall to Earth? Why don't the planets crash into the Sun? Ask a 7th grader and you usually get one of two answers: "because of gravity" (which doesn't actually answer the question) or "because there's no gravity in space" (which is wrong in two different ways). The truth lives somewhere kids never quite get to on their own. The Moon IS falling toward Earth. It just keeps missing because it's also moving sideways fast enough that Earth curves away beneath it. That's an orbit.

And that's the part of gravity that's hard to visualize. Kids understand gravity as "things fall." They've lived that. What they haven't seen is the tug-of-war between gravity pulling inward and inertia pushing in a straight line, balancing out into a stable orbit. Or how astronauts on the ISS aren't "weightless because there's no gravity" (Earth's gravity at ISS altitude is still about 90% of surface gravity); they're weightless because they're in continuous freefall, falling around the planet instead of into it.

The Gravity and Motion in Space Station Lab for TEKS 7.9B closes those gaps in one to two class periods. Kids run a fabric-and-marble "gravity well" model where a heavy ball warps a stretched sheet and marbles spiral around it just like planets, calculate their own weight on Mars, Jupiter, and the Sun using a gravity multiplier table, and sort true-from-false statements about how mass, distance, and inertia all interact. By the end, they can explain why the Moon doesn't fall, why a 100-lb astronaut weighs 38 lbs on Mars, and why an astronaut in orbit floats.

⏱ 1–2 class periods 📓 7th Grade Science 🧪 TEKS 7.9B 🎯 Built-in differentiation 💻 Print or Digital

8 hands-on stations for teaching gravity and motion in space

A station lab is a student-led activity where small groups rotate through 8 stations (plus a 9th challenge station for early finishers) at their own pace during one to two class periods. You become a facilitator instead of a lecturer. You walk around, supervise the fabric gravity well, and answer questions about astronauts and weight while kids work through the rotation.

The Gravity and Motion in Space Station Lab has four input stations (where students take in new info on gravity, mass, weight, orbits, and inertia) and four output stations (where they show what they learned). Here's what's at each one.

📷 Image slot 1 — add screenshot

📷 Image slot 2 — add screenshot

4 input stations: how students learn gravity and orbital motion

🎬 Watch It! —

A short YouTube video explains gravity assists in space travel: how spacecraft use a planet's gravity to steal momentum and change direction without burning fuel. Students answer three questions: what's the purpose of a gravity assist, why was a gravity assist necessary for the mission shown, and how does a spacecraft "steal" momentum during a flyby. The video gives kids a real engineering use of gravity that goes way beyond "things fall."

📖 Read It! —

A one-page passage called "The Force That Shapes Our Solar System" puts the student in the place of an astronaut floating between Earth and the Moon, then explains how the more mass an object has the stronger its gravity, why the Sun's enormous mass keeps every planet in orbit, why those orbits are slightly oval-shaped (the tug-of-war between gravity and inertia), and the role gravity played in forming the solar system from gas and dust. Three multiple-choice questions follow plus five vocabulary words to define: gravity, mass, orbits, inertia, and solar system. Comes in two reading levels (Dependent and Modified) plus a Spanish version.

🔬 Explore It! —

The fabric gravity-well demo. Four group members hold the corners of a stretched piece of fabric in the air. A heavy ball goes in the center to warp the fabric (the "gravity well" representing the Sun). Then kids gently roll marbles of different sizes onto the fabric and watch them curve, spiral, and settle into orbits. The bigger marble warps the fabric more on its own. Five reflection questions follow: how does the marble move, what happens as a planet gets closer to the Sun, how does this model help visualize gravity in the solar system, and most importantly what's a limitation of using this model. The limitation question is sneaky-good because gravity wells flatten 3D space onto a 2D sheet.

💻 Research It! —

Students work through 10 reference cards: definitions of mass vs. weight (mass is matter, weight is gravity acting on mass), a diagram showing how more mass equals more gravity, an Earth vs. Moon comparison (62 kg = 137 lbs on Earth but only 23 lbs on the Moon), a Gravity Multiplier table for every planet (Mercury 0.38, Mars 0.38, Jupiter 2.14, the Sun 28), the math for converting Earth weight to weight elsewhere, and an explanation of microgravity on the ISS. Five questions follow including "How would the weight of a 10 kg object change if it were on Jupiter instead of Earth?" Kids run the multiplication and discover the same object weighs over twice as much on Jupiter.

📷 Featured station deep-dive — add screenshot of the Explore It! task card

4 output stations: how students show what they learned

📋 Organize It! —

A 2-column True/False sort with 10 statements. Kids sort statements like "Gravity is a force that attracts two bodies toward each other" (true), "The amount of weight an object has affects how much gravity it has" (false; mass does, not weight), "The Moon orbits Earth because of the Sun's gravity" (false; it's Earth's gravity), and "Spacecrafts can gain speed and a change in direction by passing close to a planet" (true; that's the Watch It! gravity-assist concept). Easy to spot-check at a glance.

🎨 Illustrate It! —

Students draw the Sun, Earth, Moon, and at least two more planetary objects, then sketch each object's orbit. The trick is the arrows. Kids draw arrows showing the gravitational pull on each object, with bigger arrows for stronger pull and smaller arrows for weaker pull. The diagram makes "the Sun has way more gravity than Earth" and "distance matters" both visible at the same time. Even kids who say they can't draw end up with a useful diagram because the structure is clear.

✍️ Write It! —

Three open-ended questions: what would happen to a satellite if it suddenly stopped moving in its orbit around Earth (it would fall straight down because nothing is balancing gravity anymore), how does gravity affect the motion of planets around the Sun, and why does an astronaut's weight change on different planets and moons. The first question is the killer because kids have to articulate that orbit is the BALANCE between forward motion and gravity, not just "because gravity."

📝 Assess It! —

Three multiple-choice questions plus a fill-in-the-paragraph that uses Read It! vocabulary words (mass, solar system, orbits, inertia, gravity). Includes the question about what would happen if the Sun's gravity suddenly disappeared (planets fly off in straight lines, because of inertia) which is the cleanest test of whether kids really understand the gravity-vs-inertia tug-of-war. If you're grading the lab, this is the easiest station to grade.

Bonus Challenge It! station for early finishers

🏆 Challenge It! —

Four optional extensions: build flashcards for at least 10 vocabulary terms, write a haiku about gravity's effect on motion in space (5-7-5 syllables), diagram the motion of objects in the solar system (Sun, planets, moons, asteroids, comets), or research how gravity shaped the solar system's formation using NASA's solar system facts page and write a 4–6 sentence summary. Requires teacher approval before they start.

How this fits into a complete gravity and motion in space unit

This Station Lab is the Explore day of our full Gravity and Motion in Space Complete 5E Lesson for TEKS 7.9B. The complete two-week unit follows the 5E method of instruction and includes an Engage hook, the Gravity and Motion in Space Station Lab for Explore, PowerPoint slides and interactive notebook pages for Explain, student choice projects to Elaborate, and an Evaluate assessment.

Most teachers grab the full 5E because the Station Lab lands hardest with the days around it. But if you just need a strong hands-on day on gravity and orbital motion, the Station Lab on its own does the job.

Two options

Gravity and Motion in Space 5E Lesson cover

Full 5E Lesson $13.20 Get the 5E Lesson

Gravity and Motion in Space Station Lab cover

Just the Station Lab $7.20 Get the Station Lab

Materials needed to teach gravity and motion in space

Materials beyond what's in the download:

A piece of stretchy fabric per group for the Explore It! gravity well. A square of spandex, lycra, or even a stretched-out t-shirt works. About 2 feet by 2 feet is plenty.
One heavy ball per group to create the gravity well. A softball, a baseball, or any ball heavy enough to dent the fabric noticeably when held by four students.
Several marbles of different sizes per group to roll around the gravity well as planets. A mix of small and large marbles works best so kids can compare the orbits.
Index cards for the Challenge It! flashcard extension.
Colored pencils or markers for the Illustrate It! station.
Pencils and the printed answer sheets (included)
A device with internet for the Watch It! station (and Challenge It! research option)

Standard covered: Texas TEKS 7.9B —

Investigate and describe how gravitational force affects the motion of objects in our solar system. Supporting Standard.

See the full standard breakdown →

Grade level: 7th grade space science

Time: One to two class periods (45–110 minutes total). Plan for two periods the first time you run a station lab.

Common student misconceptions this lab fixes

"There's no gravity in space."
This is the biggest gravity misconception there is. Kids see footage of astronauts floating on the ISS and conclude there's no gravity up there. The Research It! cards on microgravity make the actual mechanism clear: astronauts on the ISS are in continuous freefall toward Earth. They keep missing because Earth curves away at the same rate they're falling. Earth's gravity at ISS altitude is still strong; the astronaut just can't feel it because they and the station are falling together. The Read It! passage reinforces this by explaining that gravity reaches across the entire solar system. The Sun, 93 million miles away, has enough gravity to hold Neptune in orbit at 30 AU.
"Mass and weight are the same thing."
Kids use the words interchangeably because on Earth, in everyday talk, they basically are. The Research It! station blows that wide open. Mass is the amount of matter in an object and never changes. Weight is the force of gravity on that mass and changes everywhere. Card 3 shows the same person (62 kg) weighing 137 lbs on Earth and 23 lbs on the Moon. Then the Gravity Multiplier table lets kids calculate their own weight on every planet. A kid who weighs 100 lbs on Earth weighs 38 lbs on Mars and 2,800 lbs on the Sun. The Write It! station forces kids to write out why the same person's weight changes on different planets, which locks the distinction in.
"Orbits are perfect circles, and planets stay in orbit because gravity gently holds them there."
Kids picture orbits as planets gliding gently along like cars on a track. The Read It! passage and the Explore It! gravity-well demo together break that picture. Orbits are slightly oval (elliptical) because they're the result of a tug-of-war between gravity pulling toward the Sun and inertia pushing the planet in a straight line. Watch a marble on the fabric. It doesn't trace a perfect circle. It spirals, wobbles, and curves. The Write It! question "What would happen to a satellite if it suddenly stopped moving in its orbit?" forces kids to confront what gravity does without inertia: the satellite plummets straight down. An orbit isn't a track. It's a balance.

What you get with this gravity and motion in space activity

📷 Inside-the-product — add screenshot of Read It passage or sample answer sheet

When you buy the Station Lab, you get a single download with everything you need:

Print version at two reading levels (Dependent for on-grade, Modified for additional support) plus a Spanish Read It! passage
Digital version as PowerPoint files (works in Google Slides too) at both levels — for 1:1 classrooms or Google Classroom
Teacher Directions and Answer Key for both versions, all keys included
Station task cards ready to print, laminate, and drop in baskets at each station
Reference cards for the Research It! station (mass vs. weight, Earth vs. Moon comparison, Gravity Multiplier table, weight calculation example, microgravity, ISS orbit, weightless astronauts)
Sort cards for the Organize It! station (10 statements to sort True or False)
Student answer sheets for each level

No login required. Download once, use forever. Reprint as many times as you want.

Tips for teaching gravity and motion in space in your 7th grade classroom

Two things make this lab go smoother the first time:

1. Test the gravity-well fabric before class.

Stretchy fabric (spandex, lycra) works dramatically better than non-stretchy fabric. A bedsheet barely warps under a softball; a stretched piece of spandex sags like a real gravity well. If you can find a piece of dance-team or cheer-uniform spandex, even a yard of it cut into squares, you'll get the cleanest demo. Test the heavy ball first too. A softball usually works; a baseball is sometimes too small to make a deep enough well. Demonstrate it once for the class so groups know what they're aiming for.

2. Pre-calculate the gravity multiplier example.

Some kids freeze when the Research It! card asks them to multiply their weight by Jupiter's gravity multiplier (2.14). The math isn't hard, but the unfamiliarity throws some students. Walk one example through with the class before they start: "If you weigh 80 lbs on Earth, how much do you weigh on Jupiter? 80 times 2.14 equals 171 lbs." Once they see the pattern, the rest is just plug and chug. Calculators are fine.

Get this gravity and motion in space activity

Gravity and Motion in Space Station Lab for 7th grade space science — TEKS 7.9B

Buy the Station Lab — $7.20

Or if you want the full two-week experience with the Engage hook, Explain day, Elaborate extension, and Evaluate assessment all included:

Buy the full 5E Complete Lesson — $13.20

(Station Lab is included)

Frequently asked questions

What does TEKS 7.9B cover?

Texas TEKS 7.9B asks 7th grade students to investigate and describe how gravitational force affects the motion of objects in our solar system. By the end, students should be able to define gravity, distinguish mass from weight, explain how gravity and inertia together create stable orbits, predict how an object's weight changes on different planets based on a gravity multiplier, and explain why astronauts in orbit appear weightless even though gravity is still acting on them.

Why is there "no gravity" on the ISS even though it's still close to Earth?

There IS gravity on the ISS. Earth's gravity at ISS altitude is still about 90% as strong as it is at the surface. The reason astronauts float is that the entire space station is in continuous freefall around Earth. The astronauts and the station are falling together at the same rate, so the astronauts never feel their weight pressing them against the floor. They're weightless in the same way someone in a free-falling elevator would be weightless. The Research It! cards on microgravity walk kids through this directly.

How long does this gravity and motion in space activity take?

One to two class periods (45 to 110 minutes total). The Explore It! gravity-well demo takes more time than most physical demos because kids need to test multiple marbles and answer five reflection questions. The Research It! gravity multiplier math also takes thinking time. Plan for two periods the first time you run a station lab. Once your class has the routine down, most groups can finish all 8 stations in one period.

Do I need to provide my own materials?

A piece of stretchy fabric, a heavy ball, and a few marbles of different sizes per group. Plus colored pencils for Illustrate It! and index cards for one of the Challenge It! options. Total cost for a class of 30: under $20 if you buy fabric and marbles new. The Watch It! station also needs a device with internet.

Can I use this in a 1:1 digital classroom?

Yes. The full digital version (PowerPoint or Google Slides) works in 1:1 classrooms and Google Classroom. The Explore It! gravity-well demo still works best as a physical center even in digital classrooms because warping fabric is hard to fake on a screen. The other stations all run cleanly in digital form.