It’s a bird, it’s a plane, it’s a… plane that flaps its wings like a bird?
Don’t laugh!
NASA scientists are currently developing an aircraft that should be able to do just that – and, as a result, be more fuel-efficient than anything else in the sky.
The trick to the wild new design is a collection of substances called smart materials. Hailed by many as the ‘next big thing’ in engineering and manufacturing, smart materials have the ability to sense a change in the world around them, and respond in some way.
Such materials include: metals that change shape when heated, crystals that produce electricity when squashed, and liquids that turn into solids when placed in an electric field.
In addition to bird-like planes, scientists are using sophisticated smart materials to create everything from clothes that monitor and control your temperature, to buildings that repair themselves after being hit by a storm.
Even more exciting is the fact that you can make your own smart material at home! You probably won’t have to search much further than your sock drawer and the kitchen to find all the equipment you need…
MAKE A SMART LIQUID
WHAT YOU NEED:
• corn flour
• vegetable oil
• 2 cups
• spoon
• plastic object (PVC works really well)
• something made from wool
WHAT TO DO:
1. Mix some corn flour and oil together in one of the cups until the liquid formed has the consistency of a runny gravy – you’ll probably need two to three times more oil than corn flour.
2. Rub the plastic object with the wool until it starts to crackle.
3. Pour the liquid past the area of the plastic that you have just rubbed into the other cup. The liquid should stop in mid-flow!
WHAT’S GOING ON?
When you mixed the corn flour and oil together you created a smart material called an electrorheological liquid. That is, a liquid that gets thicker in the presence of an electrical field. You created a field of electricity (called static electricity) by rubbing the wool against the plastic.
Corn flour and oil do not conduct electricity. However, corn flour is dielectric. That is, when it is placed in an electric field, the molecules in it become charged. This makes them stick together. In this experiment, the corn flour molecules stuck together and prevented both themselves and the oil molecules from flowing across each other – making the liquid thicker.
At least one company has developed their own electrorheological liquid and used it to create an extremely sensitive shock absorber. Scientists have also suggested that this type of smart material could be used to help design buildings that are more resistant to earthquakes, as well as in the construction of some types of safety harness.
Who knows how smart our future might become?
DID YOU KNOW?
It’s quite possible that you’ll find another electrorheological substance in your kitchen – chocolate! Scientists recently discovered that melted chocolate thickens considerably when placed in an electric field. In fact, they’ve even coined the term ‘chocolate effect’ to describe the change in thickness that electrorheological fluids suffer at the hand of electricity. Sweet!
WHAT TO DO: