Activity 1: How Do We Solve a Mystery?
Scientists use the same techniques as detectives to solve
mysteries: They gather evidence, from which they create one
or more working ideas or explanations as a basis to test their
Mystery: Why a CD player doesn't work.
What if you put a CD in your CD player, turned it on, and
nothing happened? Let's apply these mystery-solving techniques
to the question to see if they can help us figure it out.
And keep in mind that one of the most important elements in
scientific investigation is to first look for the simplest
So let's start with the simplest questions:
If you use an electrical outlet to play your CDs, is the CD
player plugged in?
If NO, this is probably the answer. That was easy, wasn't
If YES, the player is plugged in, try this:
Try the plug in another socket. Or test the socket by plugging
something else into it, a small lamp or appliance that you're
If you use batteries to play it, are they inside and intact?
If NO, this is probably your answer.
If YES, maybe the batteries are dead.
Is there some other appliance/machine that you can test
them on? Or maybe you're one of the lucky people who have
their own battery-tester.
Does the CD player look damaged in any way?
If YES, this could be your answer.
If NO, move on.
Have you tried to play this particular CD before?
If YES, and it worked before, it's probably the player.
If NO, there might be something wrong with the CD.
Try another CD. Does that work?
If YES, it's probably the CD, not the CD player. And there's
If NO, it's probably the player.
You've looked for and eliminated the simplest
answers. Now the questions get a little more complicated.
Let's try one.
Assuming the player worked the last time you used it, did
someone else use the player since then? (Here you have to
go beyond your own observations and ask the people who had
access to ityour family, possibly
your friendsif they used it.
If NO, ask someone else (until you've asked everyone you can
If YES, ask them if the player worked when they used it.
If YES, that is, they say the player worked when they used
it, something must have gone wrong between the time they
used it and now. But what?
If NO, you've at least established that someone tried to
use it and it didn't work.
To take your investigation further, you'd probably
have to do some research, which is what many scientists do
when their investigations take them into unfamiliar territory.
In this case, CD players contain extremely complex componentsthe
problem could be with the motor or the laser or some tiny
little switch. If you were determined to find out why your
CD player wasn't working, you'd have to learn more about what
makes a CD player work in the first place.