Sock Swing
Word of the day: swing
“Let's make a swing for a toy and see if we can make it go faster.”
Grab
- a long string
- a sock with a small toy or a few coins tied inside
- a table edge or doorway to hang it from
Do
- Tie the sock to a string and hang it from the table edge. Pull it to the side and let go.
- Count swings together while you count to 10 out loud. How many?
- Make the string much shorter. Guess first: faster or slower? Count again.
- Put more coins in the sock to make it heavier. Does that change it?
The big moment
Shorten the string and it goes wild.
Ask (guess first, then try)
- Short string: fast or slow?
- Did making it heavier change the swing?
What's going on (for you)
A pendulum's swing time depends on its length. Shorter swings faster. Making it heavier doesn't change the timing, and neither does how far you pull it (as long as it's not a huge swing). Grandfather clocks keep time this way.
If they want more
On a playground swing, they ARE the pendulum. Pumping legs is how they add energy.
Look it up
Wikipedia: Pendulum PhET simulation