Propelle r power A propeller has blades that push air along as the propeller spins. The blades are angled
to push the air like a wedge. The blades are twisted because they move much faster at their tip s th at at
their roots.
Air-powe red cra ft Most water craft are driven by propellers under the water. Air propellers are used for
craft tha t work in very shallow water, where a propeller would hit the bottom, or get caught in water plants.
The two most common air-powered craft are hovercraft and airboats, such as the Bottle Cata m ara n .
Why th e Bottle Cata m aran flo ats Boats float in water because the water pushes up on them. Scientists
call this push upthrust. The size of the upthrust depends on how much water the boat pushes out ofthe
way as it sits in the water. As the Bottle Catamaran floats dip further into the water, they push m oreand
more water aside, and so the upthrust get larger. When the upthrust becomes equal to the w eight ofthe
boat pushing down, the boat floats.
GREEN SCIENCE
Build a better tomorrow through education & awareness. You will like the other great Green Science k in
00-03266 Soda Can Robug
Millions of soda can are wasted everyday. Help save our
environm ent. Recycle one of them and turn it into a cool
robotic bug. Switch it on and watch it vibrate causing it
to slide across the floor. It even emits a “ buzz” as it
moves along - just like a real bug. It's an awesome
robtic science kit.
00-03267 Windmill Generator
Build this am azin g wind generator learn about
renewable energy. Watch the LE D glow as it is pow erd
by free energy from the wind. No batteries required !
Questions & Comments . ;
We value you as a customer and your satisfaction with this product is important to us. If you have comments or q ue stic is,
or you find any part of this kit missing o r defective, please do not Hesitate to contact our distributor in your c ountry, tn i
will fin d the address printed on the pack ag e. You i r e also welcome to co ntact our Marketing Support T ea m : Em ail:
infod esk@ 4m -ind .com , Fax (852) 259 1156 6, Tel: (8 511289 3 6241 , Web site: W WW 4M -IN D.COM
© 20 08 4M Industrial Developm ent Lim ite d. All rig hts reerved.
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