Orange vs White Background for Display of Data

For Teachers
1

Here are the contents of two variables: Tone (left) and Vibration (right).

One has an orange background; the other has a white background.

Does this indicate different data types? Is there more information about this in the Reference Manual? Where should I look to learn more?

Thanks …

Two Lists
Two Lists359×286 7 KB

2

TONE is a list of numbers. VIBRATION is a list of one-item lists (a matrix with one column).

3

Thank you! If I transpose the Vibration Data list, export it as a CSV, and then reimport it, it is imported as a list of numbers. Is there a more straightforward way of accomplishing this?

Thanks …

Exported & Reimported
Exported & Reimported643×175 5.56 KB

4

OK … now that I know that it is a list of one-item lists, this is one way that seems to work:

Vibrating Rod (imported data) script pic
Vibrating Rod (imported data) script pic468×161 11.2 KB

5

try this, a much more concise way:
untitled script pic

6

Or
MAP (ITEM 1 OF _) OVER VIBRATION
I think that’s the most self-documenting, but ymmv.

7

You can also use ([flatten V] of (vibration \(scaled\)))

8

“Flatten” works great! … I’m capturing the movement of the vibrating rod using MicroBlocks and a sensor connected to a vibrating rod.

I would like to do this directly in Snap! using the MicroBlocks library, but evidently the USB port doesn’t have the bandwidth to support the sampling rate required for the resolution needed. As an alternative, I’m capturing in MicroBlocks and exporting the data as a CSV file. Evidently when the CSV file is then imported into to Snap!, it comes in as a list of one-item lists.

Now that it can be transformed into a flattened list of numbers, it can be plotted, played back as a sound, etc. There’s a related activity developed by Roger Wagner that involves capturing the movement of a candle flame. The movement of a single candle flame is aperiodic due to the chaotic nature of the factors involved. Under the right conditions, three candles in close proximity will synchronize, moving in unison to create periodic motion. Can’t wait to try that next.

Thanks for the assist and the multiple solutions to transformation of the data into the form needed.

9

Is that related to the synchronization of metronomes?

10

Glen: I’m curious what sensor you’re using to collect the rod motion? What sampling rate are you using and what’s the frequency of the rod vibrations?

As you found, MicroBlocks is great for capturing data at high sampling rates. Transmitting that data to Snap! via USB is slower. So, the way you are doing this is a good solution: capture a few thousand data samples in a MicroBlocks list at high speed, then send it to Snap! at at your leisure.

11

I don’t yet know whether the factors that cause pendulums and candle flames to synchronize have any common underlying factors. This is something that I hope to learn more about as we look into this further.

12

We’re using an LED taped to a coin cell battery on the end of a metal ruler. This is a technique that Roger Wagner devised. He initially used an infrared flame sensor but then found that a classic photoresistor (“LDR” = Light Dependent Resistor) module worked just as well. Here is the general search link on Amazon:

https://www.amazon.com/s?k=ldr+module+4

There are a lot of options depending on the quantity desired. Roger used the 4-pin modules, not the ones with 3-pins, and that worked for us as well.

—–

BTW, the first time that I did this was with an Apple II computer running LCSI Logo with a swinging flashlight suspended from a string. We used the Apple II game port as an input for the light sensor.

So I was delighted that we could recreate the activity using an LED on a vibrating rod with MicroBlocks and Snap!