Sneaky Book for Boys
Page 3
Fold the top back tip down and to the left along the fold line shown in Figure 5. Then, fold the bottom front tip up and to the left along its indicated diagonal fold line, until it resembles the shape in Figure 6. Unfold the left-pointing tips back to their positions shown in Figure 5. See Figure 7.
FIGURE 1
FIGURE 2
Next, fold the top corner down and to the right in the opposite direction of how you folded it to make Figure 6. Similarly, fold the bottom corner up but to the right, until the shape appears like the one in Figure 8.
Fold the bottom right corner to the center-it will fold the figure in half. See Figure 9. While you are folding it, shape the top right-pointing corners into a mouth shape by pushing the beak with your hand. See Figure 10. If necessary, fold and unfold the figure until this section resembles a mouth.
Last, draw eyes on both sides of the top portion of the figure. Now you can pull on the two bottom corners and the mouth will flap open and close, as shown in Figure 11. If not, unfold the beak and refold it while adjusting it with your hand until the mouth moves properly.
FIGURE 3
FIGURE 4
FIGURE 5
FIGURE 6
FIGURE 7
FIGURE 8
FIGURE 9
FIGURE 10
FIGURE 11
Sneaky Origami Animator
You can add motion to your origami designs, and other craft creations, by making a Sneaky Origami Animator with everyday objects.
What’s Needed
Two large paper clips
Electrical tape
Five by three-inch piece of cardboard
Needle-nose pliers
What to Do
This project illustrates how to make a cam-crank toy to add locomotion to your still figure designs. You can produce variations on this design by using larger pieces of cardboard and stiff wire, but it’s recommended to make a simple version first. Later, you can alter the size of the parts to produce your desired results.
First, bend one paper clip into the shape shown in Figure 1. It will act as a mount for your origami figure.
Next, bend the second paper clip into the shape shown in Figure 2. It will act as a cranking cam that will move the first paper clip up and down. Wrap electrical tape around both paper clips.
Poke holes in the cardboard at 1-inch, 2½-inch, and 4-inch intervals, as shown in Figure 3. Then, stand the card along its long side and fold it into a U shape.
Push the first paper clip into the center hole. Use pliers to bend the top of the clip into a C shape so it will not fall through the hole. See Figures 4 and 5.
FIGURE 1
FIGURE 2
FIGURE 3
FIGURE 4
FIGURE 5
Next, push the second paper clip into the side holes of the cardboard so it rests underneath the first paper clip, as shown in Figure 6. Apply tape to the bottom of the cardboard to keep its shape.
Last, turn the paper clip crank on the side of the Sneaky Origami Animator and the top paper clip will move up and down. See Figure 7. Since the first paper clip has an irregular shape, it acts as a cam mechanism and causes erratic movement on the other paper clip resting on it.
You can attach small paper figures to the top paper clip with tape. Experiment with an assortment of shapes for your paper clip cam (e.g., oval or triangular shapes) to produce a variety of motion effects. See the moving-arm figure in Figure 8.
FIGURE 6
FIGURE 7
FIGURE 8
Bernoulli Principle Tricks
Sneaky Demonstrations of Air Pressure and Wing Lift
Have you ever wondered how airplanes and helicopters are able to fly? If you have, and want to demonstrate this principle, all you need are such ordinary items as straws, postcards, and strips of paper.
Air Pressure Demonstration I
An ordinary straw can be used to demonstrate that air pressure is all around us (15 pounds per square inch, to be exact). You can demonstrate this easily enough with everyday items.
What’s Needed
Straw
Glass filled with water
What to Do
Insert a straw into the glass of water, as shown in Figure 1. Next, place a finger over the top of the straw and lift it out of the water. See Figure 2.
You’ll see that the water stays in the straw and doesn’t flow out because air pressure from the bottom is keeping it in, as shown in Figure 3. When you lift your finger from the top of the straw, air pressure flows from the top and pushes against the water, forcing it out.
FIGURE 1
FIGURE 2
FIGURE 3
Air Pressure Demonstration II
You can demonstrate the power of air pressure in a more dramatic way with the following project, again using everyday items.
What’s Needed
Glass filled to the brim with water
Plastic-coated postcard
What to Do
Working over a sink, hold up the glass of water. Place a postcard over the mouth of the glass and turn the glass upside down, holding the postcard in place with your finger under it, as shown in Figure 1.
Carefully remove your finger from the postcard and you should see that the postcard will not fall. With no air in the glass to push against the postcard, the air outside presses against the postcard, keeping it in place, even with the weight of the water upon it. See Figure 2.
FIGURE 1
FIGURE 2
Air Pressure Demonstration III
What’s Needed
Paper (preferably a paper towel or napkin)
Scissors
What to Do
Cut a paper strip ½ inch wide by 4 inches in length as shown in Figure 1. Hold the paper strip up to your face above your mouth and blow. The paper naturally moves upward. Now hold the paper strip just below your lips and blow above the strip. As shown in Figure 2, the paper will also rise and move upward!
This occurs because of Bernoulli’s principle, which states that fast-moving air has less pressure than nonmoving air. The air under the strip has more pressure than the air above it and pushes the strip upward.
FIGURE 1
FIGURE 2
FIGURE 3
Figure 3 illustrates a side view of a bird’s wing, an airplane wing, a Frisbee flying disk, and a boomerang. Notice the top of the wing curves upward and has a longer surface as compared to the bottom. When the airplane moves forward, air moves above and below the wing. The air moving along the curved top must travel farther and faster than the air moving past the flat bottom surface. The faster-moving air has less pressure than the air at the bottom and this provides lift.
Baseball pitchers can take advantage of Bernoulli’s principle by releasing the ball with a forward spin. The ball produces a lower pressure below it, causing it to dip when it reaches the plate. Hence, a curveball. See Figure 4.
Sailboats apply Bernoulli’s principle to use the wind, regardless of its direction, to propel the boat in any desired direction. Figure 5 shows how altering the shape of the sail into a curve produces an effect similar to that of an airplane wing. The wind moves at a faster rate over the curved side, with a lower pressure, and the higher pressure on the other side of the sail pushes the boat laterally. A centerboard, attached to the boat hull, prevents the boat from moving sideways while allowing it to use the wind thrust to move forward. See Figure 6.
Automobile bodies are similar to an airplane wing because they are flat on the bottom and curved on top. They can lose stability at high speeds since they tend to achieve lift from the higher air pressure below, as shown in Figure 7. To reduce the Bernoulli effect, automakers have incorporated improvements in vehicle design, such as lowering the body height, adding special front bumper and fender contours, and installing rear spoilers. See Figure 8.
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FIGURE 5
FIGURE 6
FIGURE 7
FIGURE 8
Air Pressure Demonstra
tion IV
What’s Needed
Scissors
Paper (preferably a paper towel or napkin)
Two empty soda cans
Magazine
What to Do
Cut two paper strips ½ inch wide by 4 inches in length and hold them about 2 inches apart, as shown in Figure 1. Blow air between the paper strips and watch what occurs. You would expect the strips to blow apart but they actually come together, as shown in Figure 2.
FIGURE 1
FIGURE 2
FIGURE 3
Bernoulli’s principle is working here because the faster-moving air blown between the paper strips has less pressure than the air on the other side of the paper. This higher pressure pushes the strips toward each other.
Now, place the two empty soda cans an inch apart upon the slick surface of a magazine. When you blow between the cans, they will move toward each other, producing a clanging sound. See Figure 3.
Air Pressure Demonstration V
Here’s another sneaky, easy-to-perform demonstration of air pressure’s causing an unexpected result.
What’s Needed
Scissors
Piece of paper
FIGURE 1
FIGURE 2
FIGURE 3
FIGURE 4
What to Do
Cut the piece of paper into a 5 by 3-inch shape. Fold the paper in half lengthwise, as shown in Figure 1.
Next, unfold the paper and place it on a flat surface so that it has a slight rise near its center crease. See Figure 2.
Then, as shown in Figure 3, bring your face close to the surface of the table and blow underneath the paper.
You would expect the paper to rise but it actually flattens downward. The higher air pressure on top of the paper, compared to the fast-moving air beneath it, pushes the paper flat on the table, as shown in Figure 4.
Air Pressure Demonstration VI
You can use Bernoulli’s principle to perform a neat magic trick by making a ball rise from a cup and jump into another one without touching it.
What’s Needed
Ping-Pong ball
Two small cups
What to Do
This project requires small cups that are slightly smaller in diameter than the Ping-Pong ball. Since the Ping-Pong ball can barely fit in the cup, rapidly moving air above the ball will not affect the air pressure beneath it.
Put the ball into one of the cups and place it about 3 inches away from the second cup, as shown in Figure 1. Blow as hard as you can above the first cup and the ball should start to rise. See Figure 2. The force of your breath will push the raised Ping-Pong ball over to the empty cup, where it will drop inside, as shown in Figure 3. With a little practice, you can make this sneaky trick work every time.
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FIGURE 2
FIGURE 3
Sneaky Frisbee from Paper
Sneaky Flying Disk
You’ve seen how Bernoulli’s principle works. Now it’s time to put it to use and make a sneaky flyer, similar to flying disk toys, using paper and tape.
What’s Needed
Scissors
Paper, 8½ × 11 inches
Transparent tape
What to Do
Cut eight 2-inch square pieces of paper as shown in Figure 1. Fold the top right corner of one square down to the lower left corner. See Figure 2. Then, fold the top left corner down to the bottom, as shown in Figure 3.
Repeat these two folds with the remaining seven squares. See Figure 4.
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FIGURE 2
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FIGURE 4
Insert one paper figure into the left pocket of another, as shown in Figure 5. Repeat inserting the figures into one another until they form an eight-sided doughnut shape; see Figure 6. Apply tape as needed to keep the origami flyer together and turn over, as shown in Figure 7.
Next, bend up the outer edge of the sneaky flyer to form a lip, as shown in Figure 8. This outer lip will cause the air to take a longer path over it, producing a Bernoulli effect.
Turn the device so the lip is bent downward. Throw the Sneaky Flying Disk with a quick snap of your wrist and it should stay aloft for a great distance.
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FIGURE 8
Sneaky Boomerang
Want a sneaky way to play catch alone? You just need a piece of cardboard and foam rubber to make a working boomerang that will actually fly up to 30 feet away and return.
What’s Needed
Scissors
Cardboard from a food box
Foam rubber, from an old pillow
Transparent tape
What to Do
Cut the cardboard into the boomerang shape shown in Figure 1. Each wing of the boomerang should be 9 inches long by 2 inches wide.
Then, cut two foam pieces into 6 by 2-inch oval shapes with one side rising into a curve. The rising shape should resemble the side view of an airplane wing. See Figure 2. Place the oval foam pieces on the leading edges of the boomerang and secure them with tape.
FIGURE 1
FIGURE 2
Note: Look carefully at the placement of the ovals on the boomerang wings in Figure 3 before taping them. The foam creates a curved shape on the boomerang wing, which will cause air to move faster across its top than across the bottom surface. This will produce lift for the boomerang.
Hold the boomerang as if you were going to throw a baseball and throw it straight overhead (not to the side). See Figure 4. The Sneaky Boomerang should fly straight and return to the left. Experiment with different angles of throw to obtain a desired return pattern.
FIGURE 3
FIGURE 4
Sneaky Mini-Boomerang
You can use postcards, business cards, or cardboard food boxes to make a miniature, palm-size boomerang that actually flies and returns to you, for indoor fun.
What’s Needed
Scissors
Cardboard from food boxes or postcards
What to Do
Cut out the boomerang shapes shown in Figure 1. The boomerang wings can be any length between 2 to 4 inches. For optimal flight height and return performance, cut each wing of the boomerang 2 ½ inches long and ½ inch wide.
FIGURE 1
Set the Sneaky Mini-Boomerang on the palm of your raised hand with one wing hanging off. Tilt your hand slightly upward. With your other hand’s thumb and middle finger ½ inch away, snap the outer boomerang wing. You’ll discover (after a few attempts) that it will fly forward and return to you. See Figure 2.
Note: You must snap your finger with a strong snapping action to make the boomerang fly away and return properly, as shown in Figure 3.
Experiment with different hand positions and angles to control the boomerang’s flight pattern.
FIGURE 2
FIGURE 3
Sneaky Gliders
You don’t have to spend money on a balsa wood kit to make a simple working glider. A working glider, made from discarded cardboard or Styrofoam material, can produce plenty of sneaky flyers for safe fun.
What’s Needed
Scissors
Flat corrugated cardboard or Styrofoam
Transparent tape
What to Do
The sneaky glider body, or fuselage, can be cut out from the pattern shown in Figure 1. The plane will require at least one wing near the center for stability. A smaller wing near the rear rudder can also be added. Simply insert the wing(s) into the body slits and use tape to secure them properly as shown in Figure 2.
FIGURE 1
Launch the Sneaky Glider with a snap of the wrist near your ear and it should fly up to 30 feet away. See Figure 3. Test the glider wing(s) shapes to achieve various flight paths as desired.