You asked: How does a tunnel boring machine work? — Tony Marshall answered: Tunnel boring machines dig tunnels for subway systems and large water projects. For example, the channel tunnel was dug under the English Channel by huge tunnel boring machines. A TBM is shaped like a tube. At the front is a rotating disk [...]

You asked: How does an electron propulsion system work? — Tony Marshall answered: I assume that you are talking about electric propulsion systems for spacecraft. Most rockets that we see use chemical reactions to create thrust. These engines can generate a lot of power very quickly, but they are not very efficient. The problem is [...]

You asked: All the big companies have for years reported millions of pounds of profits each year. Suddenly within 6 months they are all in the red and going bankrupt. Where has all that money gone? Marshall answered: It’s a big, messy situation, but to try to simplify it a little: Businesses are having problems [...]

You asked: How does juice from concentrate work?— Charley Short Marshall answered: Juice from concentrate is really simple. You take fruit and you squeeze it to get the juice. With apples, for example, you grind up the fruit, put the pulp between sheets or fabric and apply pressure. To make the concentrate, you get rid [...]

You asked: Is it good to switch off the heater in the night after adequately covering ourselves with sweater, blanket and comforter etc.? — Singaravelu Marshall answered: If you are interested in saving money on heating in the winter, it is helpful to turn down the heater because it will lower the amount of electricity/gas/oil/wood/kerosene [...]

You asked: How does a camera film stuff? — Joshua Marshall answered: The basic idea behind a camera is to record the amount of light given off by a scene. With film, the amount of light is recorded with chemical reactions. In a digital camera, the amount of light is recorded by counting the photons [...]

You asked: How speed limits are determined/set on a stretch of road? — Kean Marshall answered: Speed limits are set by politicians and by traffic engineers. For example, there was a time in the U.S. when the federal government mandated a maximum highway speed of 55 MPH across the country. This had nothing to do [...]

You asked: Why does listening to music make people happy? — Mary Marshall answered: First, it is important to recognize that music seems to be a uniquely human activity. And music is obviously important to people. Just look at the popularity of the iPod, radio stations and music download sites. From brain mapping research we [...]

You asked: Due to knocking on my water pipes I have reduced the flow of the water through the pipes to alleviate the problem, will this affect the performance of my washing machine and dishwasher? — Roy Marshall answered: You can learn more about what is causing the knocking on this page: How to fix [...]