To the Bat Cave, Class
The mystery behind bats can have a hold on students akin to them learning about dinosaurs, but with the impact of a species that is available to see and hear today. The Wildlife Acoustics Echo Meter Touch has the power to turn this curiosity into an imaginative science curriculum with the needed hardware, software and classroom activities.
An add-on to an iPhone or iPad, the system listens for the distinctive echolocation sounds that only bats make. The kit comes with a plug-in ultrasonic microphone that is sensitive to sounds between 8- and 125-kilohertz, most of which is beyond the range of human hearing. The best part is that because the bat’s echolocation mechanism uses such high frequency sound waves, you can talk and teach while still getting a good recording.
The microphone’s aluminum case adds about an ounce and 1.8-inches to the profile of the device and is moisture resistant. Inside is a sophisticated microphone and a custom digital signal processor that is able to convert the bat’s high-frequency echolocation pi sounds into something the iPad can use and playback for kids to hear. The set-up is able to capture 256,000 samples per second and is effective as far away as 300-feet.
It works with recent iPads and iPhones, including the 5 series phones and the Mini iPad Retina model; unfortunately, it uses Apple’s new Lightning connector so early iPads and phones are out of reach. Plus, because the microphone requires the system’s Lightning port, you can’t charge the pad and use the echo microphone at the same time. As a result you need to run the pad or phone on battery power while stalking bats.
I used the Echo Meter two ways that are equally educational. I started by leaving a microphone-equipped iPad Mini on a window sill overnight with the window open to listen for the nocturnal creatures. It was able to pick up three or four bats on a good night and showed the results in a very interesting screen that displays a frequency distribution spectrogram of the soundings at the bottom with color indicating intensity and an amplitude graph at the top to show loudness.
Later I set out with several bat specialists into New York’s Central Park at dusk and captured the sounds of dozens of bats with the gear. Without the equipment I would only have been vaguely aware that things were flying back and forth overhead.
The app and hardware work together like hand in glove and the recording software is free. The Echo Meter’s Auto-ID software takes the device to a new level by recognizing the species based on its calls. At $150, it is money well spent, but the hardware and software roughly equals the price of a good iPad; teachers get a $75 gift certificate to Apple’s app store to help pay for the software. There’s no Android version available.
The combo of the two apps lets a teacher combine the visual spectrogram information and sounds with which bat it actually is. Overall, the data presentation is excellent and can help in not only teaching about bats, but it could be the basis of a great general science lessons on everything from habitat and population biology to data and graphing techniques.
The device is so sensitive that in addition to the base sound sequence, you can sometimes see subtle harmonics of the bat calls. You can playback the sequence, but with a twist that makes it incredibly useful. Rather than high-frequency sounds that nobody will be able to hear, the software slows it down to the human hearing range. At any time the app lets you add text or voice notes.
In fact, a cool game might be to play the sounds of a few types of bats and then have the class guess which ones they are. The system was able to recognize about one in three bats recorded and identified three different creatures: Eastern Red Bats, Hoary Bats and Small Footed Bats.
The Auto-ID app has a database of 25 North American and 13 European bats and the company plans to update it as time goes on. It’s like having a bat expert on hand, with each entry providing the common and scientific names as well as a nice species profile, its geographic region and what it likes to eat. In other words, it can turn any curious science teacher into a bat expert.
While you’re using the system, the iPad’s GPS receiver can be marking where you are, but only if you’re using an iPad that has a cell network data card. Later, back at the classroom, you can see where each bat was identified.
This meshes well with the kit’s curriculum. Called “Discover Bats,” the 225-page book was put together by Bat Conservation International and can be used as a self-contained course or in bits and pieces based on need and the student age group. In addition to a one-week quick study course, the kit as an excellent general introduction to bats, there are sections about habitats, species identification, echolocation and caves.
Each section has a good reading along with printed references for further study, although no Web site links. On the other hand, the iPad-based species information section has lots of links to BCI and other areas. At the end of each section, there’s a series of classroom activities and assignments along with teacher answers in the back. Finally, the kit includes a DVD that has four bat-based movies. Unfortunately, it doesn’t contain the book’s material so you’ll need to copy the worksheets rather than print them directly.
While the combined cost of the microphone and programs might seem excessive, Wildlife Associates has bulk deals for the microphone alone that brings the cost down to $450 in lots of 100. On the other hand, the curriculum can be used and reused for many years and the microphone can be passed from class to class when it’s time to study bats.
In other words, the Echo Meter Touch ends up being an economical way to teach about one of the marvels of nature.
$499; $523, with curriculum
+ Great ecology curriculum
+ High frequency microphone and software
+ Record and identify species
+ Listen to recordings
+ Spectrogram presentation
+ GPS location
- CD doesn’t contain classroom materials
- Can’t use microphone and AC power at the same time