Related Experiment Video
Updated: Jun 20, 2026

11:25
Making Sense of Listening: The IMAP Test Battery
Published on: October 11, 2010
Summary
Dr. Madeleine Ballard leads a global movement to integrate professional community health workers into healthcare systems. Her work drives policy changes for improved population health and quality care delivery worldwide.
Area of Science:
- Public Health
- Health Policy
- Social Innovation
Background:
- Dr. Madeleine Ballard is CEO of the Community Health Impact Coalition (CHIC).
- CHIC is a global movement focused on normalizing professional community health workers.
- Dr. Ballard has a PhD from the University of Oxford and is faculty at Icahn School of Medicine at Mount Sinai.
Related Concept Videos
The Quantum-Mechanical Model of an Atom
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra. Schrödinger...
Fluid Mosaic Model
Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich with the analogy of...
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
Free-falling Bodies: Introduction
All objects, neglecting air resistance, fall with the same acceleration towards the Earth's center due to the force exerted by the Earth's gravity. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavier ones. People believed that a heavier object had a greater acceleration when falling until Galileo Galilei (1564–1642) proved otherwise. We now know this is not the case.
Principle of Angular Impulse and Momentum: Problem Solving
Consider a ball of mass m, attached to a massless rod of known length, subjected to a time-dependent torque. If the initial velocity of the mass is known, then the final velocity of the mass for time t can be determined using the principle of angular impulse and momentum.
Initially, a free-body diagram of the system is drawn to illustrate all the forces acting upon the system, providing a crucial understanding of the dynamics at play. Then, the principle of angular impulse and momentum is...
Initially, a free-body diagram of the system is drawn to illustrate all the forces acting upon the system, providing a crucial understanding of the dynamics at play. Then, the principle of angular impulse and momentum is...
The Bell Curve
The normal probability distribution, often depicted as a symmetrical, bell-shaped curve, is fundamental in statistics and the study of natural phenomena. This pattern, famously described by mathematician Carl Friedrich Gauss, shows how data points are distributed around a central mean, with most values near the average and fewer observations occurring as they deviate further from it.
This pattern applies to many human characteristics beyond intelligence, such as height. For example, if you...
This pattern applies to many human characteristics beyond intelligence, such as height. For example, if you...

