← Back to course
Science Launch G3 / Week 02 / Wednesday
3/6
Week 02 · Motion Patterns

Wednesday

Build a pendulum
// Swings that repeat
⏱ about 15 min

Wednesday: Build a Pendulum

Rocket tapes a string to the edge of the table. A washer dangles from the end.

"Let's make it long and short and see what happens," he says.

Raven grabs a timer. "What do you notice if we change only the length?"

Nova hovers near the string. "Keep the weight the same," she says. "Then the test is fair."

Your investigation

You will count swings for a long string and a short string.

  • A piece of string, about as long as your arm
  • Tape
  • Two metal washers or two large metal paper clips
  • A table
  • A timer, or a grown-up who counts seconds
Safety first
Keep your face away from the swinging weight.
Swing gently. Do not spin the string around.
Nothing goes in your mouth.
  1. Tie one washer to the end of the string.
  2. Tape the other end to the edge of a table, so the washer hangs low.
  3. Pull the washer a little to one side and let it go.
  4. Count the swings for 15 seconds. Write the number.
  5. Make the string shorter by taping it higher up.
  6. Count the swings for 15 seconds again.
MAKE A PREDICTION
  • Read the question.
  • Tap your answer.
Which string will make more swings in 15 seconds?
StringSwings in 15 seconds
Long
Short
What we learnedTrue or false?
A shorter pendulum swings faster than a longer one.?
In a fair test, we change only one thing at a time.?
WHY THIS EXERCISEWe changed only the length, and the shorter string swung faster.

Reading your data

Look at your table. Compare the two numbers.

The string with more swings in 15 seconds swung faster.

You kept the weight the same and changed only the length. That made it a fair test.

THINK ABOUT YOUR TEST
  • Read the question.
  • Tap your answer.
Why did we keep the same washer for both strings?
Which string do you predict would swing the slowest of all?
What did you change in your test? Type one word.
WHY THIS EXERCISELength was the only thing you changed, so the test was fair.
Try it
Make your string extra long, then count swings for 15 seconds.
Does the extra long string swing faster or slower than before?

Awesome scientist work! Tomorrow we test something new: does a heavier weight change the swing?

← Tuesday