Lesson 7 Grades 3–5
Parachutes: coming down gently
- Timeabout 45 minutes
- WorksheetE7 Parachute drop
- Rocket Builderon the projector
Worksheets (PDF) Open Rocket Builder
Standards
| Code | In plain words |
|---|---|
| 5-PS2-1 | Use evidence to show that Earth's gravity pulls things down. |
| 3-PS2-1 | Test how balanced and unbalanced pushes change the way something moves. |
| 3-5-ETS1-3 | Run fair tests to find what to improve. |
Practice: planning and carrying out investigations. Crosscutting concept: cause and effect.
I can…
- I can build a parachute.
- I can test small and big parachutes fairly and time how long they take to fall.
- I can explain that a parachute makes drag that pushes up against gravity.
Words to know
- Parachute a canopy that catches air to slow a fall.
- Canopy the cloth or plastic part.
- Recovery bringing a rocket down safely so it can fly again.
Materials
For each group:
- Plastic grocery bags (or trash bags), string or thread, tape, scissors, a ruler
- 2 washers or binder clips per parachute (the same weight for every parachute)
- A stopwatch (or a tablet)
- Worksheet E7
For the class: a safe drop spot about 2 m high (an adult stands on a sturdy step stool, or uses a balcony or stairs).
Steps
1Hook5 min
Drop a flat sheet of paper and a crumpled one at the same time. Ask: Which one landed first? Why?
2Learn5 min
Read aloudGravity pulls everything down. As something falls, air pushes up on it: that's drag. A parachute catches lots of air, so it makes lots of drag. Soon the drag up is as big as the pull down. The forces are balanced, so the parachute stops speeding up and floats down slowly.
Real model rockets pop out a parachute near the top of the flight, so they land gently and can fly again.
On the projector: in Rocket Builder, press ▶ Watch it launch and watch the parachute open and drift down.
3Do: the drop test25 min
- Cut two squares from a plastic bag: small (20 cm) and big (40 cm).
- Tape a 30 cm string to each corner. Tie the 4 strings together to the washers.
- The adult drops each parachute from the same height. A student times it from "drop!" until it lands.
- Do 2 drops each. Also time the washers with no parachute.
- Streamer (if time): tape a paper or plastic strip (5 cm × 60 cm) to the same washers and drop it too. Is it faster or slower than the parachutes?
- Record the times on E7. Circle the slowest fall.
4Wrap up10 min
- Which fell slowest? Why? (The bigger canopy catches more air: more drag.)
- What pulled every one of them down? (Gravity.)
- Why might a huge parachute be a problem for a real rocket? (The wind carries it a long way: into trees or roads.)
Check for understanding
- Which force pulls a parachute down? Which force pushes up?
- Big parachute or small parachute: which falls slower?
- Why did every parachute get the same washers?
Answer key
- Gravity pulls down; drag (air) pushes up.
- The big one.
- To keep the test fair, so only the canopy size changes.
Teacher notes
- Safety: an adult does any dropping from a height. Students stay off chairs and tables.
- What to expect: no parachute lands in under a second; the small chute takes a little longer; the big chute is slowest. From 2 m the times are close, so good timing matters. A higher drop gives clearer results.
- Grade 3: compare by watching (which landed last?) instead of timing. Grade 5: add a medium (30 cm) parachute, or try 1, 2 and 4 washers on one parachute.
- Rocket Builder: the report's Which parachute? card shows the size the app picks for a real rocket (often 12–18 inches) and how fast it comes down (about 4 m/s, a jogging speed).
- Streamers: very light real rockets use a streamer instead of a parachute. It falls faster than a parachute but drifts less in the wind.
- Further resources: Apogee Components' free lesson The Optimum Descent Challenge (apogeerockets.com/downloads/PDFs/58-4.pdf, written for grades 5–8 with kit rockets) has more drop-test ideas for grade 5.
- Keep the best parachute to fly on launch day, taped into a paper rocket's nose.
- Parachute or streamer, on screen: the launch simulator can fly the class rocket with a parachute or a streamer. Compare how fast each comes down and how far it drifts.