Science by Email 27 July 2012

	Having trouble reading this? Try the online version | Manage your subscription
	27 July 2012
News: No pilot required By Patrick Mahony One of the unmanned helicopters in flight. You don’t always need wings to fly through the air. Helicopters might not have the natural grace of birds or the streamlined curves of jets, but they are still remarkable pieces of technology. They can move readily in all directions, as well as hovering in place. A distinctive feature of a helicopter is its set of rotating blades on top. The blades can spin around hundreds of times a minute to lift the chopper into the air. They cut through the air at an angle, creating a difference in pressure between the air above the blades and the air below. The higher pressure air below the blades pushes up, lifting the helicopter into the air. Other features of helicopter design help to keep it aloft.  For example, the body of a helicopter is made of lightweight but strong material to minimise weight and a smaller rotor on the tail helps to keep the chopper stable. The end result is an aircraft that can fly in conditions where other aircraft can’t go. For this reason, helicopters are often used in disaster and emergency situations. Project ResQu is a research project involving aerospace engineers from CSIRO, Queensland University of Technology and the aircraft company Boeing. The aim of the project is to develop helicopters that don’t need a pilot. Without a pilot, these vehicles can be built small and used in more dangerous conditions. The helicopters, called ‘unmanned aerial vehicles’ or UAVs, will be fitted with cameras and could be used during emergencies to locate people in distress. They could also be used to deliver emergency supplies, as well as in scientific research. Project ResQu demonstrates machines don’t need wings to fly and they don’t need pilots either! More information CSIRO: Unmanned aircraft to the ResQu CSIRO: Robots fly to the rescue How helicopters work Careers link Aerospace engineer
You will need a slinky.   Stretch the slinky across the table with the help of a friend.   Pull about 5 or 6 coils towards you with one finger and release. What do you see?   Pull a coil sideways and release. What happens this time?   Try this: Seismic slinky   You will need Slinky Friend Long table or bench What to do Have a friend hold one end of the slinky at one end of the table. Holding the other end of the slinky, stand at the other end of the table. Stretch the slinky tight across the tabletop. Pull about 5 or 6 coils towards you with one finger. Release your finger. What do you observe? Which way do the coils move? Keeping the slinky stretched tight, pull a coil sideways and release. Which way do the coils move this time? What’s happening? Both types of motion observed in the slinky are examples of wave motion. Waves are a way of transferring energy from one place to another. In this activity the waves move through a medium – the slinky. The medium a wave travels through can be many things, including water, air and the Earth. A medium is made up of individual parts, which in this activity are the slinky’s coils. In a medium such as air, the components are gas molecules. This activity demonstrates two types of waves. The first wave is an example of a longitudinal wave. In a longitudinal wave, the coils move in the same direction as the wave itself. An example of a longitudinal wave is sound moving through the air. Transverse waves are the second type of wave in this activity. In a transverse wave, the coils move at right angles to the direction of the wave. The ripples on the surface of water look something like transverse waves. Applications Seismic waves are caused by earthquakes. In seismology, primary waves (or P-waves) are a type of longitudinal seismic wave. In this case, the medium is the Earth. P-waves travel fastest through the Earth, and are the first type of seismic wave detected after an earthquake. Secondary waves (or S-waves) are transverse seismic waves that travel slower than P-waves, so are detected later. Both P-waves and S-waves travel deeper within the Earth. There are other types of waves, called surface waves, which travel along the surface of the Earth. Earthquakes, and particularly surface waves, can be highly destructive. Being able to detect the less damaging P-waves before the surface waves arrive can allow authorities to prepare, minimising the damage caused by a quake. In Japan in 2011, P-waves were detected with enough time for the train system to be shut down. While the earthquake was still highly damaging, stopping the trains most likely saved lives. By Patrick Mahony Try another Science by Email activity about earthquakes More information Longitudinal and transverse wave motion What is an earthquake? P-waves and S-waves Australian Seismometers in Schools Slinky drop View the online version Quiz questions 1. How many chambers does the human heart have? 2. Is a casuarina a type of a) bird, b) snake, c) plant or d) mushroom? 3. Up, down, strange and bottom are all what type of particle? 4. At room temperature, which is more viscous: honey or water? 5. Where would you be most likely to find oleic acid? Did you know? A new study suggests that it’s still difficult for scientists to predict how many different living species there are. There could be anywhere from two to 50 million species on Earth. Websites   Watch it! In the lead up to the Olympics, find out how poles for pole vault are made in this video. Hear it! Learn more about bird flu and how CSIRO is fighting it in this podcast. Quiz answers 1. The human heart has four chambers. 2. c). A casuarina is a type of plant. 3. Up, down, strange and bottom are all quarks. 4. Honey is more viscous than water at room temperature. 5. Oleic acid is found in many animal and plant fats and oils, including olive and peanut oils. CSIRO researchers have created a variety of safflower with high levels of this valuable fatty acid for industrial use. Science by Email is a CSIRO publication. bankmecu is a proud partner of Science by Email. Editor: Jasmine Leong| Manage your subscription | FAQ

 

 

---