Making a fan cart is a fun activity that will also make you realize a couple of important lessons about physics – specifically about force and motion.
What you will need:
- 1 pc 4in x 12in masonite platform
- 2 pcs 3/16 in, 6 in long wood dowels (for the axles)
- 3 pcs 3/16 in, 7 in long wood dowels (for the mast and spars)
- 1 pc 2in x 2in x ¾in thick wood block
- 2 pcs 1in x 3in x ¾in thick wood block
- 2 pcs 5in long plastic drinking straws
- 4 pcs CDs
- 4 pcs faucet washers (¼L, beveled 19/32 in O.D.)
- 1 pc 8 x ¾in sheet metal screws (pan head, Phillips)
- 7 ½in or 8in cable tie with mounting head for screw
- DC electric motor (1.5-6 volt) e.g. Kelvin 850647 or Radio Shack 273-223
- 6in 2-blade propeller (e.g. Kelvin 850889)
- 1 pc battery holder for 2 AA batteries (e.g. Kelvin 220090)
- 2 pcs alligator clips (e.g. Radio Shack 270-380)
- 2 pcs AA batteries
- 1 pc 8in x 8in manila file folder
- 7in sticky back Velcro
- hot glue gun
- hot glue sticks
- electric drill with 3/16in drill bit
- AWG (American Wire Gauge) #50 drill bit or 1/16in drill bit
- Phillips screwdriver
What you need to do:
The Cart:
- Take the masonite platform and hot glue the two straws to serve as the bushing of the dowel axles. Note the position of the CDs in the photo to estimate the position of the straws.
- Insert the 6in wood dowel in each of the straws. Place the 4 faucet washers at the ends of each dowel, 1 washer for each end of the dowel. Attach the CD to the faucet washer.
- Hot glue a 2 inch piece of velcro on one end of the platform and a 3 inch velcro on the the other end. Use the photo as reference for the position of the velcro. The 2 inch velcro is meant for the mast and the 3 inch velcro is meant for the fan.
The Sail:
- To make the sail, take the 8in x 8in manila file folder and the 2 pcs of 7in long wood dowels. Hot glue two dowels to the folder. These will be the spars. One should be 1 inch from the edge of the folder and the other 2 inches from the other end. The two dowels should be parallel to each other.
- To make the mast, get the 2in x 2in x ¾in wood block and drill a 3/16 hole in it – around ½ inch deep. On the other side of the hole, hot glue a 2 inch velcro. Insert the other 7in long dowel into this hole – using a hot glue to attach it.
- To complete the sail, hot glue the mast to the spars -intersecting the mast with the spars.
The Fan:
- Take the 2 pcs 1in x 3in x ¾in thick wood block and hot glue them together to form an L-shape.
- Take the propeller and look for the hole in the middle where you can insert it to the motor shaft (see photo). If necessary, use the AWG #50 drill to make the hole larger. This will help it slip through the motor shaft of the DC electric motor.
- On the shorter end of the L-shape, attach the small DC electric motor with the propeller. Take the cable tie and secure it to the wooden L-shape by using the metal screw (see photo above).
- Place a velcro at the bottom of the battery holder and the inside of the L-shaped wood. See the photo above to note the position of the battery holder against the propeller.
- Take the wires from the battery holder and cut one of them to make it shorter than the other. This will keep them from touching each other when attached to the motor. Strip the ends and attach the alligator clips.
To assemble the cart, place the mast, fan and battery holder based on the position of the velcros. connect the wires of the battery holder to the DC electric motor using the alligator clips.
What should happen:
- When the fan is facing the sail as per photo, the cart will not move.
- When the fan is facing the other way and blowing air away from the sail, the cart will move forward.
- When the fan is removed from the cart, held by hand and is blowing air towards the sail, the cart will move forward.
- When the sail is removed and the fan is blowing towards the vacated place of the sail, the cart will move backwards.
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