Sometimes when you look into a swimming pool it’s difficult to tell how deep the water actually is. If you grab something long, like a stick, you can use it to test the depth of the water. Upon ...

This film demonstrates the measurement of the speed of light in both air and water using experimental setups. The first experiment involves measuring the time it takes for light to travel a known ...

For the first time, scientists have demonstrated that negative refraction can be achieved using atomic arrays - without the need for artificially manufactured metamaterials. Scientists have long ...

THERE is in Upper Thibet a plateau called the “Kyan Chu Plain,” on which phenomena of mirage are frequently seen. The plain is at a height varyingfrom 15,000 to 16,000 feet. A cold wind comes down ...