# The Domino Effect :: Science Saturday

Frequently, the munchkins will entertain themselves watching videos on YouTube … Buddy searches “Lego Trains” or “HO Trains” while Sweetie will search “Polymer Clay” or “Paper Crafts”.  I was surprised to discover that what caught their attention this past week were Dominoes.  They spent hours watching videos and then trying to set up similarly complicated patterns.  They even used my iPhone to record their own videos and take photos of their designs before they were made to fall.

All the while they played investigated the properties of dominoes and experimented, I kept thinking to myself,  “We should really be doing schoolwork.  We have quite a list of tasks that are due next week.”  Then inspiration struck … “What they are doing is science!  So I ran into the dining room where they had set up their testing space.  “I have a challenge for you both,” I said as I gave them a stopwatch and a meter stick.    “How does the distance apart affect how fast dominoes fall? You might try and find out … maybe at 2cm apart and at 4cm apart.”  I then walked away.

They had some experience recording their results in the past with other experiments so not wanting to interfere – or take over as I have a tendency to do – I left this one up to them.  Upon completion of their test, we sat down with their results table and discussed how it all meant.

The Domino Effect

Purpose: This investigation will determine whether the speed of sound is affected as it travels through a solid, liquid, or gas.  In this experiment, think of the dominoes as molecules that make up a solid, liquid, or gas.  Sound travels in waves or moving molecules.

Materials
box of dominoes
smooth surface
ruler or yardstick
stopwatch or a watch with a second hand

Procedure

1. Line up dominoes approximately 2 cm apart, stretched out over a 100-cm length.
2. Measure the time it takes for all the dominoes to fall. Be sure to start the timer just as you knock over the first and stop it just as the last domino hits the surface.
3. Record the amount of time it took for all the dominoes to fall.
4. Line up the dominoes again, this time 4 cm apart, stretched over a 100-cm length.
5. Predict the amount of time it will take the dominoes to fall and record your prediction.
6. Measure the time it takes for all the dominoes to fall. Be sure to start the timer just as you knock over the first and stop it just as the last domino hits the surface.
7. Record the amount of time it took for all dominoes to fall. How close was your prediction to the actual time?
8. Set up both lines of dominoes so that they each stretch to 100 cm, but one line should be placed 2 cm apart and the other line 4 cm apart. Lines should be parallel to each other.
9. Knock the first domino of each line over at the same time. What do you notice?