EcoMOBILE: Integrating augmented reality and probeware with environmental education field trips

Abstract

The ability to understand ecosystems is richly enhanced by experiences in real 76 environments. Field trips, both real and virtual, support gains in science knowledge 77 (Bitgood, 1989;Garner & Gallo, 2005;Gottfried, 1980;Knapp & Barrie, 2001); and 78 outdoor experiences can affect student attitudes about nature (Ballantyne & Packer, 2002;79 Manzanal, Rodriguez Barreiro, & Casal Jimenez, 1999;Bogner, 1998). Yet, the real 80 world can be a challenging learning environment; students may be distracted by the 81 novelty of the social and physical context of the experience and find it difficult to focus 82 on relevant learning tasks (Falk, 1983;Orion & Hofstein, 1994). Students may be 83 overwhelmed by a flood of information and may find it difficult to know where to devote 84 their attention. As a result of these and other logistical factors, field trips tend to be one-85 time experiences with limited connection to what students experience in the classroom 86 curriculum or in their everyday lives. 87 88 Using handheld devices and probes in science has been shown to promote various aspects 89 of teaching and learning in the classroom and in the field. Using probes in a lab setting 90 coupled with computer-mediated presentation of the results promotes critical evaluation 91 of graphs and data (Nachmias & Linn, 1987 between abstract representations and concrete experiences with the data and related 97 concepts (Vonderwell et al., 2005). 98 99 We posit that combining probes and handheld devices through the use of augmented 100 reality (AR) can further support this learning by situating the data collection activities in 101 a larger, meaningful context that connects to students' activities in the real world (Squire 102 & Klopfer, 2007). AR is an "immersive" interface (Dede, 2009) utilizing mobile, context-103 aware technologies (e.g., smartphones, tablets), and software that enables participants to 104 interact with digital information embedded within the physical environment (Dunleavy & 105 Dede, in press). Our research is exploring the unique affordances of AR that can support 106 this kind of situated learning in environmental science education. 107 108 Combining AR and the use of environmental probes can provide multiple affordances in 109 support of situated learning during field trip experiences. AR interfaces can enable 110 contextualized, just-in-time instruction; self-directed collection of real-world data and 111 images; and feedback on student actions and responses. AR's have also been shown to 112 support social interactivity; respond to shifts in context; facilitate cognition distributed 113 among people, tools, and contexts; and provide individualized scaffolding (Klopfer & 114 Squire, 2008; Klopfer, 2008; Dunleavy & Dede, in press). We hypothesize that a 115 combination of both AR and environmental probes may enhance the field trip experience 116 in ways that neither technology could accomplish on its own. 117 118 Through smartphones enabled with augmented reality technology, and environmental 119 probes comparable to those used by environmental scientists (Texas Instruments 120 NSpire™s (TI NSpire™s) with Vernier probes), we are conducting pilot implementations 121 of a curriculum that scaffolds authentic participation in scientific practices by middle 122 school students. For our pilot studies, this article describes the extent to which using this 123 combination of technologies aided students' learning of ecosystem science concepts and 124 their attitudes toward ecosystem science. The EcoMOBILE curriculum included one class period before the field trip, the field trip 203 itself, and one class period after the field trip. The learning goals of the field and 204 classroom activities focused on understanding of the relationship between biotic and 205 abiotic factors, data collection and interpretation skills, and the functional roles (producer, 206 consumer, decomposer) of organisms in an ecosystem. 207 208

Pre-Field Trip 209
Prior to the field trip, the students also had access to "learning quests", which are online 210 modules providing a 5-10 minute activity that introduces the students to the ideas behind 211 dissolved oxygen, turbidity, and pH. These provide a definition of the water quality 212 variable, the range of values that students might expect to see, and information about why 213 the value might change. Two of the teachers used these learning quests during class two 214 days before the field trip, while the 3 rd teacher used them as one of the "stations" during 215 the activities on the day prior to the field trip.

217
During the school day before the field trip, teachers conducted a pre-field trip classroom 218 lesson in which students practiced using the probes to measure temperature, dissolved 219 oxygen, turbidity, and pH. The classroom had 5 stations -one for each of the 4 220 measurements -plus a final station where students measured all four characteristics for a 221 classroom aquarium. At each station, students measured both a control of plain water and 222 a source that would provide an extreme reading for the measurement being tested. For 223 example, in order to test pH, the students took measurements for both tap water and 224 vinegar. Students worked in teams to visit each station for about 5 minutes. Afterward, 225 the groups gathered to review their results and discuss the range of readings for each 226 measurement type. 227 228

Field Trip 229
Each class went on a single field trip to the same local pond, adjacent to a district-230 managed Ecology Center staffed by a program director who leads all school field trips. 231 Therefore, instruction during the field trip experience was consistent across all classes. 232 The field trips lasted approximately 3.5 hours. The activities during the field trip included 233 the following: 234 • The program director presented an orientation about the pond (20 minutes) 235 • A research team member provided an introduction to the FreshAiR™ program using 236 the smartphones and reminded students how to use the probes in conjunction with the 237 smartphones (15 minutes) 238 • Students participated in the EcoMOBILE experience at the pond, described in detail 239 below (1 hour) 240 • While at the pond, students also helped the program director collect macro-and 241 micro-organisms from the pond using nets (10 minutes). 242 • Break for lunch (20 minutes) 243 • The teacher led a discussion about the data they had collected (20 minutes) 244 • Students observed pond organisms under a microscope and made sketches of the 245 organisms they saw (1 hour) 246 247 For the EcoMOBILE experience, students were assigned to pairs; and each pair collected 248 data on two water quality variables, either temperature and dissolved oxygen or pH and 249 turbidity. Within each pair, one student was given the smartphone to carry, the other the 250 TI NSpire™ and probes ( Figure 1). Students were told to switch roles halfway through 251 the experience so that each had a turn with each technology.

253
The EcoMOBILE experience included the following AR-facilitated activities: 254 • Upon arriving at a hotspot near the pond, students working in pairs were prompted to 255 make observations about the organisms around the pond and classify (producer, 256 consumer, decomposer) an organism they observed. Students answered questions 257 about their observations, and received constructive feedback based on their answers. 258 • At the next hotspot, students were prompted to collect water measurements using the 259 TI NSpire™ and environmental probes. The AR delivered additional information that 260 helped them make sense of the measurements they had collected. Student recorded 261 their data on a worksheet. 262 • Students were then prompted to collect water measurements at a second location that 263 they could choose. Students once again recorded their data and were prompted to 264 compare the two measurements. 265 • At a later hotspot, students were prompted to sketch on paper an organism they had 266 observed near the pond. 267 • Two more hotspots provided visual overlays, 3D models, videos, and additional 268 information related to consumers and decomposers, as well as posed questions related 269 to the role of these organisms in the ecosystem. 270 • As the final activity in the field, students met with another pair of students who had 271 collected the other two water quality variables, and the two pairs compared their 272 measurements before returning to the classroom.

274
The augmented reality program specifically supported students' use of the probes by 275 helping them navigate to a location to collect a sample, providing introductory 276 information just-in-time for student use ( On the next school day after the field trip, back in the classroom, students compiled all of 283 the measurements of temperature, dissolved oxygen, pH, and turbidity that had been 284 taken during the field trip. They looked at the range, mean, and variations in the 285 measurements and discussed the implications for whether the pond was healthy for fish 286 and other organisms. They talked about potential reasons why variation may have 287 occurred, how these measurements may have been affected by environmental conditions, 288 and how to explain outliers in the data.

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In summary, the EcoMOBILE activity was designed to provide opportunities for both 291 real-world observation and interaction separate from use of the technology (e.g., time for 292 un-mediated observation and sketching on paper), as well as interactions with 293 technology-centered objects including videos and 3D visualizations. In order to reinforce 294 our learning goals, we aimed to take advantage of the affordances of both real and virtual 295 elements available to the students. 296 297 298 3. Data Analysis and Results 299 300 3.1 Affective Data Analysis 301 302 We assessed students' self-efficacy related to ecosystem science knowledge and skills 303 and their valuation of environmental monitoring. Students indicated, on a Likert scale, 304 their degree of agreement with statements related to ecosystem science skills and 305 attitudes. The Likert scale used was: "strongly disagree", "disagree", "neutral", "agree", 306 "strongly agree". We analyzed the data with a factor analysis to assess aggregation of 307 these items around proposed latent traits, and found that we could use a single factor to 308 represent the information in the affective assessment items. Therefore, the seven Likert-309 scale questions were aggregated to a single mean affective score for each student, and 310 pre-post gains were assessed using a paired t-test on these aggregate scores.

312
Based on the debate around use of parametric versus non-parametric tests on Likert data 313 (Norman 2010), we analyzed the item specific results using both approaches. Upon 314 witnessing a significant overall effect on the pre-post mean per student, we analyzed each 315 item independently using a paired Wilcoxon signed-rank test and paired t-test to detect a 316 change in the distribution of student responses to each item. Also, a Kruskal-Wallis test 317 along with ordinary least squares linear regression were used to determine whether 318 teacher or the pre-intervention content survey scores were significant predictors of gains 319 in affective scores, according to the hypothesized population model below: where _ ! is the mean gain in affective score (post-pre) for student (i), ! is the 323 mean score on the pre-intervention content survey for student (i), ! is a 324 categorical variable designating teacher for student (i), ! is the residual, ! is the 325 intercept, and ! designates the regression coefficients for each predictor. To test for 326 OLS assumptions of linearity, we plotted pre-content scores against gains and visually 327 verified a linear relationship between them. We inspected plots of residuals against 328 predicted values of gains, as well as normal probability plots, to verify assumptions of 329 residual homoscedasticity and normality in the sample.

331
During one field trip, a film crew from a major telecommunication company attended the 332 field trip to capture footage of students using wireless handheld devices during field trips. 333 We found that this particular class showed strong gains on the affective survey for all 334 items, despite chilly and rainy weather during the trip. We inferred that student attitudes 335 may have been confounded by the importance and excitement they felt in association 336 with the filming. We therefore eliminated this particular group from our analysis of the 337 affective data, but included these students in the analysis of content gains, given no 338 apparent difference between this class and others on the content survey results. 339 340 3.2 Affective Results 341 342 Overall, student responses to affective items showed a positive shift in their attitudes 343 about their ability to understand focal topics and do science related skills. The mean 344 affective score increased by 0.26 points (pre_mean = 3.88 ± 0.5, post_mean = 4.14 ± 345 0.58), with a moderate effect size of 0.48, meaning that the average increase in student 346 scores was about one half of a standard deviation. Teacher and pre-intervention content 347 scores were not significant predictors of the mean gain in affective measures.

349
The item-specific analysis showed that the most significant gains were observed on 350 prompts related to understanding what scientists do ( self-efficacy in using graphs and tables (Item 2), and importance of taking measurements 353 (Item 7). There were no differences in statistical outcomes of the parametric and non-354 parametric tests, therefore we present the results of parametric paired t-tests in Table 1. 355 Post-hoc comparisons indicated that teacher and scores on the pre-intervention content 356 survey were not significant predictors of the gains in student affective measures on these 357 items ( Student responses to content assessment items were scored right or wrong, and student 364 scores on the pre and post surveys were aggregated to a total score per student (total score 365 was the total number of questions a student answered correctly out of 9). A paired t-test 366 was used to determine whether changes in pre-post scores were significant. Given 367 significant gains in the overall student scores, we fit a multiple regression model to assess 368 whether gains could be predicted by teacher based on the hypothesized population model 369 below: 370 371 where i designates the student of interest, GAIN is the student gain on the post-374 intervention survey (post-intervention score -pre-intervention score), TEACHER is a 375 categorical variable that designates the teacher for student (i), ε is the residual, ! is the 376 intercept, and ! designates the regression coefficients for each predictor. We inspected 377 plots of residuals against predicted values of gains, as well as normal probability plots, to 378 verify assumptions of residual homoscedasticity and normality in the sample.

380
Performance on individual items was assessed using McNemar's test to determine 381 whether significant numbers of students transitioned from a wrong to a right answer on 382 each item. Finally, we used ANOVA to assess whether there were significant differences 383 in the pre-survey scores among teachers or among class periods, in order to determine 384 whether there were pre-existing differences among the teachers or class periods that 385 could have affected interpretation of the results. 386 387 3.4 Content Understanding Results 388 389 We witnessed significant learning gains on the content survey (T (70,1) = -8.53, based on 390 paired t-test). Students' scores went up by an average of 19% from the pre to post survey 391 (Mean_pre = 4.3 ±. 1.8, Mean_post = 5.9 ± 1.9, based on 9 total points) The effect size 392 associated with these gains was substantial (1.0), indicating that student gains were 393 equivalent to one standard deviation around the mean of the data. Teacher was not a 394 significant predictor of the student gains in content understanding (F (2, 68) = 1.83, R 2 = 395 0.02, p-value = 0.17). The mean scores on the post surveys for each teacher were 396 teacher1 = 6.6, teacher2 = 5.2, teacher3 = 5.6, thus teacher2 had a significantly lower 397 post-intervention survey score compared to the other teachers (F(2,68) = 3.76, p-value = 398 0.03). Also, pre-survey scores were significantly lower (F (2,68) = 4.12, p-value = 0.02) for 399 one of the teachers participating (teacher1 = 4.9, teacher2 = 4.3, teacher3 = 3.6). 400 Therefore, there were differences between teachers in the pre-and post-intervention 401 content scores, but these differences did not manifest as significant differences among 402 teacher in overall gains in content scores.

404
Analysis of the item-specific results indicates that student gains were significant on topics 405 related to the water quality variables that were measured with the environmental probes. 406 Gains were significant on questions 8, 9 and 10 (Table 1). On questions related to food 407 webs, abiotic/biotic resources and graphing (Questions 11-14), students generally 408 demonstrated a high level of understanding of these concepts on the pre-survey (greater 409 than 64% of students got these questions correct). Again, on the post survey, greater than 410 72% of students answered these assessment items correctly. 411 412 3.5 Student Opinion Post-Survey 413 414 In addition to understanding how student affect and content understanding changed 415 during the intervention, we also asked students to offer their opinions about the field trip 416 using a one-time field trip opinion post-survey. On this survey, students were asked "On 417 a scale of 1-7, how much did you like the EcoMOBILE field trip? Circle your answer.
(1 418 = dislike very much, 7 = liked very much)." The average answer was 5.4, indicating that 419 students generally enjoyed the field trip (Q1, Figure 7). Subsequent questions asked about 420 different features of the activity; students average rating of each activity was 4.6 or above. 421 Technology-rich activities tended to receive the highest ratings, e.g., 6.0 for the 3D 422 visualization triggered by image recognition (using Qualcomm Vuforia technology) (Q7), 423 5.7 for answering embedded questions (Q5), and 5.6 for earning virtual badges (Q8). 424 Less technology-focused activities tended to receive lower ratings, e.g., 4.6 for making a 425 sketch on paper (Q6), or 4.9 for learning about decomposers through reading on-line 426 instructions (Q4 Prior to the field trip, two of the teachers had expressed concern that the smartphones 469 might be too engaging; leading students to ignore the real environment in favor of the 470 media and capabilities provided by the smartphones. Post-field trip comments indicated 471 the contrary was true -teachers noted that the smartphones promoted interaction with the 472 pond and classmates.

474
It felt like 90% of the time they were at the pond environment, they were working 475 on interacting with the pond and their partner, whereas previous times it felt like 476 it was maybe 60 or 50% of their time they were independently interacting. ~ 477 Teacher1 478 479 Two of the four teachers mentioned that one of the most productive aspects of the 480 experience were hotspots where the AR platform and environmental probes were used to 481 show something that could not be seen in the real world (e.g. measuring abiotic variables 482 like dissolved oxygen and pH, seeing a starch molecule in a ducks stomach). Another use of AR that teachers believed was successful was in leading the students to do 492 something active in the real world, for example using the smartphones to navigate to a 493 hotspot where they were then instructed to collect a sample using the environmental 494 probes. Teachers noted that using the smartphones and environmental probes helped the 495 students become familiar with interpreting the water quality measurements, and noted 496 that students were able to apply these ideas in other situations. 497 498 "They do seem pretty conversant with turbidity, pH, dissolved oxygen and I would 499 say more conversant with those things than [students from previous classes]… 500 501 The teacher went on to explain a different part of her curriculum in which they were 502 reading about acid rain, and she said, 503 504 …they were all like "whoa!" when it said that acid rain had a pH of 1.5 -5.5, 505 they KNEW -fish can't live in that. You know, like, they had that sense… 506 ~Teacher1 507 508 Finally, other observations of the teachers indicated that allowing the students a window 509 into the unseen parts of the environment also helped students to identify with scientific 510 practices and motivated students in a new way, 511 512 My Teachers commented that the smartphones helped to structure students' movement 531 through space and guided their interaction with the pond and with classmates. The 532 students were able to work independently, at their own pace, with the teacher acting as a 533 facilitator. Teachers reported that the activities were more student-driven and less 534 teacher-directed. The teachers thought this was beneficial in that it provided students with 535 a different sense of ownership over the experience. 536 537 It helped structure their movement through space…so rather than having a whole 538 group of kids clustered in one muddy, wobbly spot at the edge of the pond, they 539 were all at sort of different spots going through it at their different paces and 540 because they were moving independently through the different parts, I felt like it 541 gave them a different ownership over the experience than if there had been just 542 one teacher voice and a crowd of kids. ~ Teacher1 543 544 Another feature of the activity was the opportunity for collaborative communication and 545 problem-solving among students that arose from the augmented reality experience. 546 547 It invited much more student on student dialog because they had to engage 548 together to sort of figure out things that were coming through to them on the 549 smartphone. So it, in some ways, I thought that their dialog probably deepened 550 their understanding. ~ Ecology Center Program Director 551 552 One teacher observed that the students seemed to rush through some of the information 553 presented on the smartphones, while the Ecology Center Program Director, who guides 554 the field trips for all the students in the school district, lent perspective saying: 555 556 having done a lot of ponding with the kids without smartphones and seeing how 557 they often rush through things anyway… if anything, I was struck that the kids 558 were sort of … paced through the activities more than usual ~ Ecology Center 559 Program Director 560 561 562 Written feedback from the teachers indicated that AR was particularly useful in engaging 563 students. Two teachers were neutral (rating of 3) in their self-reported assessment of the 564 contribution that the smartphones and FreshAiR™ made toward student learning, while 565 one teacher gave a rating of 5 (assessed using a Likert scale, where 1 = very little and 5 = 566 very much). In comparison, all teachers rated the TI NSpires™ and environmental probes 567 as a 4 or a 5 for their contribution toward student learning. These results are based on the 568 teachers' self-reported impression of students learning gains, rather than empirical data. 569 The results of our student opinion and content surveys support the idea that the 570 smartphones supported high levels of student engagement, while the student learning 571 gains were most apparent on items related to the combination of AR and probeware. 572 573 3.6.3 Issues to Resolve in Future Implementations 574 575 Teachers spoke of managing the tension between positive aspects of student engagement 576 and students' desire, negative in its effects on learning, to speed through an activity 577 without fully reading or comprehending the activity in order to see what is next. As noted 578 above, one teacher found this tension common to any field trip with or without 579 technology, yet it remains a challenge to design experiences that meaningfully engage 580 students in the tasks at hand so that the take home message is meaningful, not just novel. 581 In future research, we plan to design interventions that allow students to use these 582 technologies during multiple field trip experiences in order to examine whether novelty 583 attenuates and engagement is sustained. We hypothesize that situating these learning 584 experiences in local environments and equipping students to use technologies that allow 585 them to collect data and observations that are meaningful outside of a classroom context 586 should lead to sustained engagement beyond that offered by the novelty of the 587 technologies themselves. 588 589 The teachers also expressed concern about the ability to manage the technology and 590 devices when orchestrating the field trip on their own. During the experience, our 591 research team was on hand to guide students and address any technological problems. 592 This means that on each field trip, there were at least four adults involved: the teacher, 593 field trip coordinator, and two members of our research team. Additionally, the research 594 team charged, transported, set-up, and calibrated the smartphones and TI NSpire™ 595 probes. In the field, student pairs managed a smartphone and TI NSpire™ with relative 596 ease, yet the teacher felt they may not have sufficient resources to prepare the devices 597 ahead of time for the field experience if working alone. with the technology, and also with science. Students' engagement with the technology 606 was also evident in their responses to the opinion post-survey, in which technology-rich 607 activities were rated higher than those without technology. 608 609 Feedback from the teachers suggested that the type of engagement observed was in using 610 the devices as "ready-to-hand" (Soloway, Norris, Blumenfeld & Fishman, 2001), which 611 is a concept initially conceived by Heidegger (1927Heidegger ( /1973

and described by Pea and 612
Maldonado (2006) as "a condition of interacting with the world as mediated through the 613 use of objects when we care about them, objects whose design allows us to remain 614 engaged in the tasks to be accomplished, rather than to focus on the devices themselves." 615 Other researchers argue that handheld technologies (like smartphones or tablets) are 616 uniquely positioned to achieve this immediate relevance and utility, as students may use 617 tools and media that are not dictated by the curriculum (Klopfer & Squire, 2008), and the 618 activities can draw on tools and techniques that may be available to them outside of the 619 classroom and can be used during future informal learning opportunities (Klopfer, 2008, 620 p. 58). Equipping handheld technologies with augmented reality applications can scaffold 621 student use of scientifically relevant tools and modes of communication (Squire & 622 Klopfer, 2007) and could support subsequent participation in meaningful scientific 623 communities of practice. 624

626
Positive effects on student engagement observed by teachers were mirrored in the 627 positive gains we saw on student responses to the affective survey. We observed gains in 628 a number of affective items and saw particular gains in student self-efficacy and their 629 understanding of what scientists do. These findings echo other research that has shown 630 that technology integrated with field trip experiences can engage students in inquiry-631 based activities and help students identify with scientists and scientific practices ( Using augmented reality on the field trip allowed teachers to use pedagogical approaches 643 that may otherwise be difficult in an outdoor learning environment. The technology 644 supported independence, as students navigated to the AR hotspots to explore and learn at 645 their own pace. This freed the teacher to act as facilitator, an affordance of AR that has 646 been hypothesized by other researchers (Roschelle & Pea, 2002 Such feedback suggests that AR can provide a powerful pedagogical tool that supports 658 student-centered learning. Given the positive effects of student-centered approaches on 659 higher-order skills such as critical thinking and problem solving (McCombs & Whisler, 660 1997), these technologies may support the use of sophisticated pedagogical approaches of 661 great benefit to student learning. They can encourage active processing thus helping 662 students to develop deeper understanding, discover gaps in their understanding, and 663 realize the potential for transfer in similar contexts (Perkins, 1992). Since student 664 strengths and preferences for learning are very diverse, these technologies provide ways 665 of individualizing instruction in a group setting, fostering increased motivation and 666 learning (Dede, 2008;Dede & Richards, 2012). Thus, AR may provide an extension of 667 technologies that have already been identified as supporting student-centered learning in 668 the classroom (Hannafin & Land, 1997).

670
The teachers indicated that the technology promoted more interaction with the pond 671 environment and with classmates compared to field trips in past years. The teachers 672 stated that they began this project with skepticism about whether the technology would 673 overwhelm the experience, holding the students' attention at the expense of their noticing 674 the real environment. However, teachers and investigators found the opposite to be true. 675 Students were captivated when a squirrel dropped a seed from a tree near the path and 676 nearly hit a classmate; they called out excitedly when they observed a frog near the shore. 677 Meanwhile, the AR offered students a view of bacteria and molecules -parts of the 678 ecosystem that students would not otherwise have been able to witness in the field.

680
Such affordances of AR support student recognition of non-obvious or unseen factors as 681 significant actors in ecosystem dynamics. This addresses a long-standing challenge in 682 helping students to recognize the existence of microscopic and/or non-obvious causes 683 (e.g. Brinkman & Boschhuizen, 1989;Leach, Driver, Scott, & Wood-Robinson, 1992). 684 The tendency to miss non-obvious causes is especially prevalent in student thinking when 685 there is a salient, obvious candidate cause. The affordances of AR enable non-obvious 686 causes to compete with more obvious ones for students' attention.

688
Following directions embedded within the FreshAiR™ program, students were guided 689 through collection of meaningful water quality measurements and were immediately 690 prompted to reflect on the measurements and make sense of the data followed by 691 feedback that clarified or reinforced relationships among variables. This adds a 692 dimension to use of probeware and enhances its affordances by decreasing cognitive load 693 associated with data collection and interpretation, and increasing collaboration among 694 students (Roschelle, 2003 probeware helped to situate the measurements in a meaningful context, and "act becomes 697 artifact" as students were able to carry the data they had collected back into the classroom 698 (Roschelle & Pea, 2002). The results of our pre-post surveys support the conclusion that 699 the activities which integrated probeware resulted in significant learning gains related to 700 student understanding of water quality variables. Teachers also reported examples in 701 which students were able to apply what they had learned to a new situation in interpreting 702 the effects of acid rain on aquatic organisms.

704
The gains found in student comprehension of water quality metrics and application of 705 these ideas in the classroom context show real promise. Given the relatively brief 706 exposure to the technologies in the field in comparison to the typical length of a unit of 707 study, many questions remain to be answered. These include questions about the 708 persistence of the gains here, about the relative impact of the technology versus the 709 classroom curriculum used to support field activities, and also about the possibilities 710 afforded by longer interventions. Future studies that offer insights into the effects of 711 different dosage levels as well as assessment of the persistence of the student gains are 712 needed. These would guide efforts to assess the appropriate level of use both in the field 713 and classroom. Given the salience and contextualization of the experience for students, 714 we expect that the gains would persist beyond those of typical instruction; however, these 715 are empirical questions yet to be addressed. 716

717
Teachers reported high levels of student engagement with the smartphones, but written 718 survey results from the teachers indicated mixed opinions about the specific impact of the 719 smartphones on student learning. Teachers' surveys indicated a strong feeling about the 720 effectiveness of the probeware for supporting student learning, while the AR was rated 721 more neutrally on this same question. Through analysis of observations, survey responses, 722 and interviews we concluded that, in this use case, AR was most effective as a mode of 723 engagement and as a way of structuring and enhancing the probeware-based activities of 724 the field trip. This speaks to the importance of design objectives during the development 725 of AR activities, as our primary goal here was to use the AR to support integration of 726 probeware into the field trip experience. The overall EcoMOBILE experience contributed 727 to significant student learning gains; however, based on our research design, it is not 728 possible to assess the relative impact of different aspects of the experience. Our findings 729 indicate that AR activities can be effectively designed to serve a facilitative or mediating 730 role that supports student-centered pedagogies and integrates real-world activities into a 731 learning experience, which is complementary to AR activities designed for direct 732 instruction. Further insight will be gained as we continue to work closely with teachers to 733 better understand how AR can serve instructional goals and support student learning.

735
Our findings suggest that combining AR with use of probes inside and outside of the 736 classroom holds potential for helping students to draw connections between what they are 737 learning and new situations. Uncued transfer is enhanced by authenticity (Brown, Collins 738 & Duigid, 1989) where the surface level problem features are closely aligned-signaling 739 to students the possibility that a transfer opportunity exists (Goldstone & Sakamoto,740 2003). We think that AR and TI NSpire™ with probeware used together can guide 741 students through a scaffolded, but authentic scientific experience. Situated investigation 742 in the real world may facilitate transfer and may enable "preparation for future learning" 743 (Bransford & Schwartz, 1999) in that students learn skills that may be applicable to 744 learning more generally, for instance, the tendency to consider how to apply school-745 learned skills in the real world. Considerable effort can be expended in trying to help 746 students transfer their knowledge from the classroom to the real world. Bringing 747 technology enhancements into the real world makes application of the field trip clear.

748
Transfer can then focus on applying knowledge to other real world contexts (Schwartz,749 Bransford & Sears, 2005).

751
Overall, results of the students' surveys and teacher feedback suggest that there are 752 multiple benefits to using this suite of technology for teaching and for learning. For 753 teaching, AR can be harnessed to create a learning experience that is student-centered, 754 and provides opportunities for peer-teaching, collaboration, and one-on-one teacher 755 guidance. The scaffolding provided by the AR platform enabled student use of 756 sophisticated measurement devices that would otherwise have been difficult to manage. 757 These benefits to the teacher helped to unlock different learning opportunities for 758 students. We plan to continue exploring the affordances of this combination of 759 technologies for promoting transfer of student learning between classroom and real world 760 environments.  Figure 2. Introductory information about dissolved oxygen in a pond. 926 Figure 3. Instructions to student to use the probe at designated hotspot. 927 Figure 4, Multiple choice question soliciting the students input based on water 928 measurement captured with probeware. 929 Figure 5. Feedback when student captures a water measurement that is within the 930 appropriate range. 931 Figure 6. Feedback when a student captures a water measurement that is outside the 932 expected range for the pond. (Image credit: © John Lund/Sam Diephuis) 933 Figure 7. Mean student responses on the opinion survey following the field trip activity. 934 The items were scored on a 7-point Likert scale, and the mean value on the graph is 935 surrounded by error bars that indicate the standard error around the mean. 936 937 Table 1. Summary of results for specific assessment items. Results for questions 1-7 are 938 reported in mean Likert score; questions 8-14 are reported in the percent of students who 939 answered the item correctly. Changes in the affective measures were assessed using 940 paired t-tests, while the content measures were assessed using McNemar's test. 941 Table 2. Predictors of gains in affective scores between the pre-and post-intervention 942 survey. The model was fit using ordinary least squares regression. Teacher and content 943 pre-survey score were not significant predictors of gains (F (3,48) = 0.82, R 2 = -0.01, p-944 value = 0.49) 945 Table 3. Predictors of the gains in the content survey scores (where gain = post content 946 score -pre content score). The model was fit using ordinary least squares regression.