An optofluidic volume refractometer using Fabry–Pérot resonator with tunable liquid microlenses

This letter reports the development of an optofluidic Fabry–Pérot (FP) resonator, which consists of a microcavity and a pair of liquid microlenses. The microcavity forms part of the microchannel to facilitate sample injection. The liquid microlenses are used for efficient light coupling from the optical fiber to the microcavity. The liquid microlens collimates the diverging light from the optical fiber into the FP cavity, which provides real-time tuning to obtain the highest possible finesse up to 18.79. In volume refractive index measurement, a sensitivity of 960 nm per refractive index unit (RIU) and a detection range of 0.043 RIU are achieved.     

Accuracy of Pedometer in Walking and Running

Abstract

Two experiments were conducted to examine the accuracy of mechanical pedometers in walking and running. Groups of 20 volunteer subjects were used in each experiment. In experiment 1, subjects wore 4 identical pedometers on the waist during six 1-mile walks on a motor driven treadmill, two at each of 3 speeds: 2, 3, and 4 mph. Experiment 2 required subjects wearing 5 pedometers to perform two 1-mile walks at their own pace under each of two different conditions: (1) on a 400 meter track and (2) along a jogging path over a measured mile. These subjects also completed two 1-mile runs at their own pace over the same measured mile course. In both experiments, a two-way ANOVA with replicates showed significant effects of subjects, condition (speed), and subjects-condition interaction. Test-retest reliability coefficients ranged from ?0.13 to 0.81. Results of these studies indicate that the ability of the mechanical pedometer to measure distance is inconsistent. The findings indicate that pedometers are more accurate for some individuals than others. Also their accuracy varies with the speed of walking and is different for walking compared to running.     

Posing Problems for Open Investigations: What questions do pupils ask?

The purpose of this study was to (a) find out the types of questions that pupils ask for open-ended science investigations, and (b) discuss how teachers can help pupils to identify problems and pose questions that are feasible for investigations. The study was conducted in a class of 39 primary 6 pupils of mixed ability. The pupils wrote down questions for two investigations that they would like to work on. The questions for the first investigation were generated individually, but those for the second investigation were posed in groups after the pupils were shown some examples of investigable questions. Among the questions that were posed individually, only 11.7% could be answered by performing hands-on investigations. Most of the questions asked were based on general knowledge and covered a wide range of topics. However, when questions were generated in groups after examples were shown, there was a significant increase in the number of questions that were amenable to science investigations (71.4%) but they related to fewer topics. A typology of investigable and non-investigable questions is proposed. Suggestions on how teachers can help pupils to pose problems and questions that are feasible for investigations are given.