Hi, I'd like to introduce you to our Go Direct Light and Color Sensor,
and to illustrate its use, I'll conduct one of our more popular
middle school science experiments, The Reflectivity of Light.
To start with, let's take a look at the sensor.
You can see here that there are actually four different openings on the face
of the sensor.
The first one, the top one, is the light sensor, just the visible light
associated with that.
Then next down the list here is actually a white LED, so white light source.
We can turn that on to illuminate our experiments, very handy for the experiment
that we'll be running today.
Next in line is a red, green, and blue sensor that measures the relative
contributions of red, green, and blue light for color analysis.
And finally, we have a broad-spectrum UV or ultraviolet light sensor.
To start the experiment, I'm going to press the Power button and we
should see the red LED start to flash on the sensor, meaning it's
available for connection.
On my Chromebook, I'm going to launch Graphical Analysis for our software
for Go Direct Sensors.
When I launch the software, we get three different options
for data entry.
We get sensor data collection, data sharing, and manual entry.
I'm going to select Sensor Data Collection for connection to our Go Direct Sensors.
You'll notice that we have a long list of sensors available here and if I don't see
my sensor immediately on the top of the list, I can use a handy tool on the
sensor itself, the serial number, which for our case ends
in the numbers 474.
I can sort by serial number using this filter.
So, I'm just going to type in the number 474 and you'll notice that that just
isolated to the one sensor that I was interested in connecting with.
Clicking on that we have now connected with our sensor.
You'll note that on the sensor face, the LED is now blinking green, indicating
that we've connected to the Chromebook.
I want to show you where you can change sensor channels if you so desire.
For other experiments, you might want to look at UV light or
the color spectrum.
In our case, this is how you would do that just by clicking on Sensor Channels and
choosing the channel you are interested in.
Since we're using the Light channel, that's just the default,
it's already connected.
I'll just click on Done to go back to the graph.
The reflectivity lab calls us to use the Meter setting for the
Graphical Analysis software.
So, to get to a meter setting, I'm going to go to this icon up here,
which is the View icon.
Click on that and choose Meter.
Now, we get a live readout from the sensor.
Very easy to read at this point.
Next, I want to set up my equipment according to the experiment criteria.
So, I'm going to place our sensor in a clamp so that I can orient it above the
table about two inches.
I might put that up a little bit higher.
Somewhere between five centimeters plus or minus.
I'm going to turn on the light by pressing on the Power button and I want this
oriented as straight up and down as possible.
There, that looks pretty good.
If I put my white paper under the light sensor, you'll notice that the sensor
reading increases dramatically, indicating that we have some good reflection coming
off of that white paper.
In the experiment, we're going to first do white and black and then we'll investigate
a couple of different colors.
I've chosen a pink piece of paper and blue for my two other samples.
So, to start data collection, actually, I could just write down this number that's
about...you can see it jumps around a little bit though.
So, we might want to get just an average number by actually doing
some data collection.
So, I'm going to press Collect.
I'm now collecting 10 seconds of data.
The Stop button will change to Collect again when the data collection is done.
There we have that.
Now, if I wanted to use the Statistics function of the software,
I could go back to the graph and I can just click on this icon and look
at view Statistics, and it will tell me that the median or the mean value
is 704 lux.
You could also just use an average value you're reading off the meter if
you wanted to.
Let's go back to the meter reading.
The next thing I'm going to do is collect some data for the black paper,
so I'll put that underneath the sensor and I can hit the Collect button again
to start my data collection.
You'll notice that this is quite a bit lower, about 45 plus or minus lux,
which are the values for the light sensor.
And our 10 seconds has elapsed, so I can then look at this on our graph
as well and you'll notice that this just has the latest reading,
just that approximately 44/45 lux for the black paper.
If I want to look at both of my datasets, I can click over here on the Y-axis label
and I can select both of the datasets and here we have the white paper reflected,
and here we have the black paper reflected.
Click outside of that box to close that and click again and I can get values there
if I wish.
I can also run statistics on this to get values as well.
At this point in the experiment, it may be very useful rather than just
having students take additional data for the two additional sheets of paper to have
them sit and think about what they predict the values are going to be for the pink
paper and for the blue paper.
It's a great activity to kind of force them to think a little bit more
about the experiment, think about the nature of reflection,
and have a discussion in their lab group.
Once you're done with that, we'll go back to the meter screen and
we'll collect two more sets of data.
Let's start with the pink.
Put that under my sensor, instead of using the Collect button this
time I'm just going to hit the space bar.
It's an alternative for data collection.
There we have 10 seconds of data collection and finally, the blue sample.
There's my blue piece of paper underneath the light sensor and once again,
hitting the space bar to collect data.
Okay.
We have all of our data collected now, let's go back and look at this
on the graph.
So, again, to see all four sets of data, I'm going to click on the label
of the Y-axis.
I'm going to select each of the four datasets, and we can see it here that we
have the white and the black, and in between, we have the pink and the blue.
Now, your students have all the data they need to complete their lab analysis.
It's a great time for them just to reflect on the nature of light and color.
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