• Dedication
• Introduction
• I discovered this discovery
• Discovery 0: Preparation
• Discovery 1: Open your XO
• Discovery 2: Buttons and bits
• Discovery 3: Turn XO on, and observe
• Discovery 4: Turn XO on. Now what?
• Discovery 5: Button functions
• Discovery 7: Other bits of the XO
• Discovery 6: Icon Ring
• Discovery 9: List view
• Discovery: Help
• Discovery: Frame
• Discovery 10: Wireless networking
• Discovery: Browse
• Discovery 8: Good questions
• Discovery: Journal
• Discovery: Record
• Discovery: Paint
• Discovery: Write
• Discovery: Collaboration
• Discovery: Frame Again
• The Undiscoverable: Terminal
• Discovery: Utility Menu
• Pause
• Discovery: More Activities
• Discovery: Puzzles
• Discovery: Games
• Discovery: Turtle Art
• Discovery: Calculate
• Discovery: Measure
• Discovery: Etoys
• Discovery: Music
• What do I want to discover?
• Discovering childhood education
• Discovery: Hints
• Resources
• Discovery: Glossary

Discovery: Measure

Go to home view and find the Measure activity icon. You may be in some doubt as to what you can measure using a computer, and if so, write down your questions as usual. Does the icon tell you anything?

Click Measure. What do you see?

 

Figure Measure initial display.

Make notes as usual.

Many people will discover something at this point that you can't get by simply looking and poking buttons or icons. Under some circumstances it would be very difficult not to make this discovery. But it is not certain, so after you look, poke, and make notes, I will give you a broad hint, and then tell you some things that are really undiscoverable.

Hint: Make some sound. Speak, sing, clap your hands, play a musical instrument if you have one handy, turn on the radio, TV, CD or DVD player. What do you see on the screen? How does it depend on the sounds you make, or the sounds around you?

Now poke some more. How do the toolbar controls change what you see for the same sounds?

The Undiscoverable: Some people will know from prior experience with scientific instruments that the XO is displaying a waveform of a time-varying signal in Measure, and some might even recognize that one of the controls changes from the waveform display to a frequency display. Others may have no idea what any of that means. Much of what is going on here is not discoverable in any ordinary way.

 

Measure frequency display for alto recorder (a wooden flute, no electronics)

 

Measure frequency dispay for B-flat clarinet.

Flutes of various kinds sound rather different from clarinets of various sizes. Can you tell anything from the displays shown above? There is a mathematical relationship to be discovered here. Several, actually. The first goes back to the Pythagorean discovery of the mathematical basis of harmony, namely the overtone series. The second is which overtones appear in the display for the clarinet. I will leave the rest of the explanation as a mystery for now, since such matters are well outside the discovery of the XO and Sugar. You can look it up on Wikipedia or ask someone knowledgeable.

But before we get to that, how does the sound get to the activity so that it can put up a screen display? Through a microphone, obviously, but where? Do you remember from Record? If not, how can you tell where the microphone is? When you find something that might be a microphone, can you test whether it is? The answer is yes.

Now I will assume that you have done that, and tell you a few more seriously Undiscoverable things about measurement on computers. Well, somebody discovered them, but almost everybody else needs the explanation. That is true for most important scientific and mathematical discoveries past a certain point. Or if not the complete explanation, at least some very broad hints.

Measure can display signals that come in through the built-in microphone, as you have seen. It can also use an external microphone plugged into the sound port, or indeed any signal coming in through the sound port in the range of 0-1 volt.

USB?

This covers a wide range of devices for measuring all sorts of things, such as temperature, pressure, force, acidity, and so on through a wide range of physics, chemistry, and biology. Even with no external instruments, we can explore the whole realm of sound: music, speech, and acoustics in general. We have hardly begun to discover what all of this means for teaching science and engineering subjects with Sugar, but we know that the options are extensive, and that a lot of people will spend a lot of time working them out. Including the children.

Names: An electronic instrument for measuring waveforms is called an oscilloscope. A digital version, with all sorts of extra software for analyzing waveforms is naturally called a digital oscilloscope. Measure software makes the XO do the work of a digital oscilloscope that used to cost far more.