Hong Kong has been covered many times by many people in this style. The density of the city screams for these sort of compositions. I never really acted on these instincts, the idea of copying someone else really throws me off.

The thing is, when I really think about it, everything has already been done. Why should I limit my self because photography has been around for all this time, so here we are…


DIY 2 Liquid Density Science Experiments for kids. For more popular kids’ science experiments go here: unicornhatparty.com/tagged/science

Go here for the Liquid Density Tower Experiment Tutorial below and the layered layered fancy drinks I posted here

A street scene in the capital city, Kigali.

Rwanda’s urban population is predicted to grow two-and-a-half times greater than its current size by the year 2020. Rwanda already has the highest population density in Africa but in the coming twenty years, statistics place the urban population growth at greater than three times the rate of the total population growth.

Sustainable employment opportunities in both urban and rural areas of Rwanda are a concern.

Image and caption by Juan Herrero, via Instagram. Rwanda, 2015.


Sailors have long known about the “dead water” phenomenon, which can bring ships to a near-standstill, but it was only within the last century that an explanation for the behavior was found. The underlying cause is a stratification of fluids of different densities. As seen in the video above, when a boat moves by exerting a constant force, such as with propellers, it generates an internal wave along the interface between two density layers in the water. As the wave grows in amplitude, it speeds up, chasing and eventually breaking against the boat. The energy that drives the internal wave’s growth comes from the energy the boat expends for propulsion; the larger and closer the wave gets, the slower the boat goes because its energy is sapped by the wave. In the ocean, particularly near sources of freshwater run-off, like melting glaciers, the water can be extremely stratified, with many layers of different salinity and density. The end of the video simulates this with a three-fluid demonstration in which the boat’s motion generates internal waves across multiple density interfaces. (Video credit: M. Mercier et al.)

Wave clouds

Boundaries in the atmosphere can act like the boundary between oil and water; if you shake a container you can mix them, but if you just rock it, you’ll set off a wave at the interface between the oil and the water.

These are Undulatus asperatus or wave clouds photographed over South Carolina on the morning of March 30. These clouds form when there is a boundary between 2 layers of different density and something disturbs that boundary. The boundary is pushed up in one spot, it comes down next to it, and that sets off a wave that carries downwind.

Undulatus Asperatus clouds aren’t an official type of cloud yet, but their name has been submitted for consideration to become the first new type of cloud in a half century (read more here: http://tmblr.co/Zyv2Js1W0T-MY)


Image credit:
Danny Buxton and Amy Anderson of Smoaks, SC via @bryluhn on Twitter
Shared here and here with permission:


Head over to our blog for video of these clouds rolling through: http://tmblr.co/Zyv2Js1hC3j2T