Friday, July 27, 2012

TI-Nspire Vernier DataQuest Collection Setup

Inquiry and Problem-Based Learning are a couple of ideas you hear about in education recently. Teachers want students to be engaged with real-world situations and actual data collection.
The TI-Nspire is a great tool to collect and analyze data . When using the TI-Nspire with a new probe or sensor it will automatically detect it and set up a default configuration, so that the student can just press the green collect data button (or TAB to the green arrow and press ENTER). However, there are times that the students may decide that they want to collect data for a longer period of time or, as is the case with a light sensor and a fluorescent bulb, perhaps they only want to collect data for 0.05 seconds and yet get a couple hundred "Number of points."  So you can either right-click from the left details panel or press MENU, Experiment, Collection Setup...
The following screen appears which has raised questions from first time users of DataQuest: What is a Strip Chart, and can I get more information about Data Markers? 
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The following is my attempt to shed some light on these options. 

Strip chart: Imagine a heart rate monitor at a hospital. Once the time of collecting data is displayed, this strip of graphed data moves to the left. This is nice to use when you want to start the data collection, but you don't want it to stop until you get some 'good' data. For example perhaps you only want one good bounce or so of a ball. You could decrease the time from the default 5 seconds, to 2 seconds and keep the collection going until you see a good bounce.  (Regarding ball bounced, try holding/positioning the CBR2 at a nice height where it is not distracted by nearby objects and ZERO and REVERSE the sensor.)

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Regarding data markers. Here is an example of some data that can be used to explore the linear relationship between the strength of the magnetic field B (in milliteslas) and the current I (in amps) in an electromagnet or solenoid, a coil of wire.  The relationship is B= mu-naught * n*I, where n is the number of coils per length and mu-naught is a fundamental constant of nature. It is always a real delight to 'discover' constants of the universe right in the classroom. E.g. bounce a ball and you can easily experimentally determine acceleration of gravity on the surface of the earth. 

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Notice that each set of data has a marker that displays at regular time intervals. I think part of the reason this appears by default is for the sake of those who are not enjoying the color of the TI-Nspire CX or for colors that may appear similar.

There seems to be a difference between Point Markers (pick which shape you want for which list of data) and Data Markers. ***

Under menu, Options, Point Options...
You can choose to not connect all the data points and you can see that the default is regional, but can be changed to mark none or all.
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You can add Data Markers after the data is collected. I right clicked (ctrl menu) in the details panel on the left to get the option. See the screen shot below.
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This marker shows up in the table, by making that data point bold and it appears when the data is presented in other formats. Notice the extra big blue circle below.

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What you are asking about is wondering about the options in the Collections Setup.
If this box is checked, you will not get any dots.

*** Update [I just received some additional information that I think will be of interest to those who search and find this site.] 
Inline image 6"Point markers are specific to identifying which column is which.  They are a kin to the TI-84 Stat Plot Mark option.  The defaults are Regional for Time-Graph collections and All for events with entry or selected events collections.  In the case you are using the Melt Station*, the Point mark option is set to None (because we also use Data Markers with that sensor). 

A Data Marker is used to annotate a graph with specific points of interest.  The annotation appears as an extra big point mark (on the graph) and a bold entry in the table.  The data mark can include text to identify points.  In math, you might collect a set of data and have students go in and mark and label several points of interest (relative max/min, points of inflection, etc.). In science, you might be identifying other things like when a color change happened in a reaction or when stirring began.   

Data Markers can be added after collection or can be set up to add during collection (which is automatically done for the Melt Station*).  When you chose the option to use Data Markers during a collection (from the data collection setup menu), we set the point marks to none.  This makes it so you will only show the points of interest that you mark.  To mark a point during collection, press the camera icon (Like the Keep button) and the next collected point will be marked (notes can be added after collection is complete).  You can mark as many points as you want. The marked points are shown in the Details menu to the right of the graph. 

*The Melt station needed this functionality.  This lab apparatus is used to find the melting point of organic solids which melt over a range of temperatures.  Data Markers are used to identify when the organic substance first starts to melt and then when it is completely melted.  These are added during collection.  By default, Data Markers is checked in the data collection setup menu for this sensor. 

In "Science with TI-Nspire Technology", we made use of data markers in several of the labs.·        
Lab 7 Dew Point – we mark the point when dew first starts forming on the can.·         
Lab 17 Ventilation and Heart Rate – we mark the point when you start holding your breath or start hyperventilating. ·         
Lab 27 Ball Toss – We mark (after collection) when you started to toss the ball, when the ball left your hand, when the ball is at its maximum height, when the ball is first caught, and when the ball comes to rest in your hand.  What is neat about that is you mark the position graph and since the marks are related to time, you get marks on velocity and acceleration as well