Dry sand piles up in front of an object you may try to drag around, such as a huge block of stone to build a pyramid, for example. Wet the sand though and small water droplets bind the grains together. Researchers at the University of Amsterdam experimented in the lab with sand, water and a laboratory version of the

that was used in pyramid building. With the correct quantity of water, wet desert sand is about twice as stiff as dry sand and only half as much pulling force is required. And that's hugely important if you're building a pyramid in the desert. While this finding helps us understand the pyramids better it's also relevant for working with materials such as asphalt, concrete and coal which are significant materials in worldwide energy consumption. Which begs the question: how did they transport bulk water across the desert for wetting the sand?

RUNNING ON SUNSHINE: European scientists have demonstrated that they can take carbon dioxide and water, add concentrated sunlight, and produce liquid hydrocarbon fuels. While individual elements of the production chain have been around for a while, the demonstration showed that those parts can be made to work together as a process. While the scientists produced a small amount of jet fuel, the process could also create any other type of fuel for transport applications, such as diesel, gasoline or pure hydrogen. The more valuable CO2 is as a source material the less likely we'll be to just throw it into the atmosphere.


RUBBISH FUEL: British Airways is setting up a factory that will turn household rubbish into jet fuel. First hazardous and recyclable materials will be removed. Then the rubbish will be combusted to produce a synthesis gas of hydrogen and carbon monoxide, which is then converted to liquid fuel. The goal is for BA to obtain 30% of fuels from renewable sources by 2050. The airline say that turning trash into fuel yields twice the energy that incinerating the waste for electricity would provide. It sounds as though household rubbish is starting to have some value.

SUN ON THE WATER: The ThermalSquare water heater uses direct sunlight to help you save on power bills. The prototype solar water heater is about the size of a satellite dish. It uses two dishes stamped out of sheet metal. One, about 1.2 metres in diameter, focuses sunlight onto a second, smaller mirror. That mirror sends a concentrated beam of sunlight onto a water intake pipe that leads to the hot water tank. The system is designed to heat water up to 60C, but no hotter and store it in the water tank for later use. The device can heat 180 litres of water from 15C to 60C every day. Add-on modules will allow the unit to provide cooling or generate electricity using heat exchange. That's a handy way to bypass electric circuits and sophisticated technology.

OPEN AND SHUT: The Chui door monitor incorporates an HD camera with a speaker, WiFi, RGB LED, and some smarts. The system uses facial recognition and can play messages intended for specific recipients. It can hook into Internet connected locks to open the door for certain visitors and connects with a smartphone app so you can talk with visitors without actually walking to the door. It can also read QR codes and alphanumerics. Just wait till the kids program the door to lock you out as a practical joke. >

Miraz Jordan,