The widely used PASCO laboratory equipment is an excellent way to introduce students to many topics in physics. In one case, PASCO's equipment may be too good! Various experiments exist for calculating the kinetic coefficient of friction by measuring the acceleration of a sliding object under some constant force. With ever more accurate equipment,…

A pair of fine tweezers and a steady hand may well be enough to pick up a grain of sand, but what would you use to hold something hundreds of times smaller still, the size of only one micron? The answer is to use a device that is not mechanical in nature but that relies instead on the tiny forces that light exerts on small particles: "optical…

Mounting clinical evidence suggests that abnormalities of social engagement in children with autism are present even during infancy. However, direct experimental documentation of these abnormalities is still limited. In this case report of a 15-month-old infant with autism, we measured visual fixation patterns to both naturalistic and ambiguous…

Forty toddlers aged 20 to 24 months were presented with 32 pairs of images with the auditory stimulus Look followed by the name of the target image (e.g. "Look...tree") in an intermodal preferential looking (IPL) paradigm. The same series of 16 items was presented first with one image as target and then with the other member of the pair as target.…

Human walking is a complicated motion. Movement scientists have developed various research methods to study gait. This article describes how a high school student collected and analysed high quality gait data in much the same way that movement scientists do, via the recording and measurement of motions with a video analysis tool and via…

Silos and bunkers have been allies in the development of kinesiology for nearly 50 years. Silos of specialization allow us to go toe-to-toe with researchers in parent disciplines, compete for grants, and otherwise spread our academic wings. The bunkers of utility and generic movement provide an important degree of legitimacy for a subject matter…

An inexpensive and easily implemented device to measure wind velocity is proposed. This prototype has the advantage of being able to measure both the speed and the direction of the wind in two dimensions. The device utilizes a computational interface commonly referred to as a "mouse." The mouse proposed for this prototype contains an…

We present a case study of the physical principles necessary to model the high altitude parachute jump made by Colonel Joseph Kittinger, USAF, in 1960, in order to determine the maximum speed attained and to calculate whether this speed was sufficient to exceed the speed of sound at that altitude. There is considerable discrepancy in the value of…

This article describes an activity that can be performed with an inexpensive plastic toy popper. The activity builds skill at analysing motion and results in the calculation of a surprisingly extreme acceleration. (Contains 1 figure.)

According to a prominent theory of human perception and performance (M. A. Goodale & A. D. Milner, 1992), the dorsal, action-related stream only controls visually guided actions in real time. Such a system would be predicted to show little or no action priming from previous experience. The 3 experiments reported here were designed to determine…

Too often, students in introductory courses are left with the impression that Einstein's special theory of relativity comes into play only when the relative speed of two objects is an appreciable fraction of the speed of light ("c"). In fact, relativistic length contraction, along with Coulomb's law, accounts quantitatively for the force on a…

In electric or mixed electric-mechanic systems, the distinction between potential and kinetic energy is not as clear as in purely mechanical systems. A solution for the motion of an inductively loaded rail generator is presented. In this case, the magnetic field energy (1/2)Li[superscript 2] can be written "formally" in terms of a potential…

Background/Hypothesis: The degree of attention directed to a stimulus and the presence of anisometric representations can alter the perception of the magnitude of a stimulus. We wanted to learn if normal right-handed subjects' estimates of distance traveled are influenced by the right-left direction or hemispace of movements. Methods: We had…

We investigate the problem of the horizontal distance travelled by a mobile experiencing a quadratic drag force. We show that by introducing a normalized distance, the problem can be greatly simplified. In order to parametrize this distance, we use the Pearson VII function, and we find that the optimal launch angle as a function of the initial…

Mothers modify their actions when demonstrating objects to infants versus adults. Such modifications have been called infant-directed action (IDA) or "motionese" (Brand, Baldwin, & Ashburn, 2002). We investigated the IDA features of interactiveness and simplification by quantifying eye gaze, object exchanges, and action units enacted…