Sneaky Book for Boys
Page 2
Try balancing the can on a surface and even on your finger. For dramatic effect, act as if it takes lots of effort and skill to keep the can balanced.
FIGURE 1
FIGURE 2
Tie a Knot with One Hand without Letting Go of the String
Here’s a sneaky dare you can make with a friend. Challenge your friend to pick up a length of string or rope and tie a knot using only one hand. After your friend’s failed attempt, you’ll execute this one-handed trick. You can also perform this trick with a tightly wound scarf.
What’s Needed
String, rope, or scarf
What to Do
First, place the string over your hand, but not your thumb, with one end hanging a few inches lower over the right side of your hand as shown in Figure 1.
Next, pull up the longer end using your middle and forefingers. See Figure 2.
FIGURE 1
FIGURE 2
Wiggle your hand as you let the longer length of string pull through the short end, which now encircles it. Let the loop that has formed slip over the back of your hand as the long end pulls through the center. Keep wiggling your hand and soon the string will fall into a loose knot as shown in Figure 3.
Last, say “Presto!” and allow the string to drop down into a knot as shown in Figure 4.
FIGURE 3
FIGURE 4
Tie a Knot with Two Hands without Letting Go of the String
After amazing your friend with the one-handed knot-tying trick, dare him to pick up a length of string (rope or a tightly wound scarf will also work) with the forefingers and thumbs of both hands and tie a knot without letting go.
What’s Needed
Two-foot length of string, rope, or a rolled up scarf
What to Do
First, place the string in front of you on a table, then cross your arms as shown in Figure 1.
Next, grab one end of the string with one hand and then position your arms so you can pick up the other end with your other hand. See Figure 2.
Last, uncross your arms and the string will magically tie a knot on its own as shown in Figure 3.
FIGURE 1
FIGURE 2
FIGURE 3
Step through a Postcard
You can win quite a few bets by performing this simple trick. Ask a friend to cut a hole in a postcard large enough to step through. Your friend can’t cut strips and tape them together though.
When your friend fails to accomplish this feat, you can quickly make sneaky cuts in the postcard and amaze your onlookers.
What’s Needed
Postcard
Scissors
What to Do
Figure 1 shows a typical postcard. Fold the postcard in half, widthwise.
Note: You can also perform this trick with a piece of paper, a business card, and so forth.
Using the scissors, cut along the lines shown in Figure 2. You can add more lines if desired but there must be an odd number of lines that alternate from the top and bottom of the postcard.
Next, unfold the postcard and cut across the three lines shown in Figure 3.
Last, pull the postcard apart along the cut edges until it forms a large circular shape large enough for you to step through. See Figure 4.
FIGURE 1
FIGURE 2
FIGURE 3
FIGURE 4
Sneaky Color from Black and White
Challenge your friends by asking them to change the color of an item without touching or painting it. Then amaze your friends when you actually produce colors from a black-and-white image with this next trick.
What’s Needed
White cardboard
Black marker
Pencil
Pin
Scissors
What to Do
Draw the disc shown in Figure 1 on the white cardboard. Ensure that half the disc is solid black and half has the broken circle picture. If you photocopy the illustration, be sure to fill in blank spots with a marker. The disc should be approximately 4 inches in diameter. Cut out the disc with the scissors.
Place the disc on the center of the pencil eraser. Secure the disc to the eraser by pushing the pin into the eraser through the cardboard. See Figure 2.
Next, place the pencil between your palms and spin it. You’ll see the black-and-white image turn blue and red depending on the speed, as shown in Figure 3.
How It Works
Your eyes have rod cells for peripheral, or side, vision, and cone cells for front vision and for discerning color.
There are three different types of cone cells that each respond to red, green, and blue at different response times. When you see white, all three cone cells respond equally. When you spin the disc, the alternating black sections, with their different lengths, cause an imbalance to how the three cone cells respond to white and your cone cells cause you to “see” different colors.
FIGURE 1
FIGURE 2
FIGURE 3
Hand-powered Fan
As you may know, hot air rises. Rising heat can be made to move objects, and you can demonstrate this fact with a novel “hand-powered” motor. In this demonstrational science project, your hands will actually provide the heat to demonstrate how moving air currents can move an object in a rotary motion.
All it takes is an ordinary piece of paper, scissors, a needle, a cardboard box, and your hands.
What’s Needed
Paper
Scissors
Sewing needle
Small cardboard box
What to Do
Cut a piece of paper into a 2-inch square. Fold it in half diagonally; then unfold it and fold it in half on the other diagonal, as shown in Figure 1. This should create a cross-fold with a center point.
FIGURE 1
You can use a paper-clip box or similar small box as a mount for the needle. Hold the needle on its side with your fingers and carefully twist it into the top of the box (or use a thimble) until it punctures a hole in the top. Place the piece of paper on top of the needle so its center point allows the paper to turn freely. See Figure 2.
FIGURE 2
To make the sneaky “motor” turn, rub your hands together back and forth about twenty times to generate heat and place them near the sides of the paper. After a few seconds, the paper will begin to spin (Figure 3).
The paper spins because the heat on your hands causes a temperature increase in the air around the paper. As the heated air rises and cooler air takes its place, the air movement pushes the paper sides, causing it to rotate like a motor.
FIGURE 3
Sneaky Break String without Scissors
Have you ever failed to break a length of string no matter how hard you tried? Want to look like a hero with super strength when others fail this test? This neat trick will also come in handy when scissors aren’t around.
Note: This sneaky trick will work on thin cotton string, not with nylon or coated string.
What’s Needed
Cotton string, approximately three-feet long
What to Do
Wrap one end of the string three times around the forefinger of your left hand and then make a small loop near the palm.
FIGURE 1
Next, pull the string behind your left hand and up and through the loop, and leave a 1-foot length between your hands.
Last, wrap the string at least four times around your right hand. To break the string, make a strong fist with both hands. Bring your fists together with your left hand on top, then rapidly drop your right hand. The string should break in the area of the loop. See Figure 1.
Note: First try this sneaky trick with thin string and then gradually try stronger string.
Levitating Art Figures
You can make everyday things balance in sneaky ways when you know the secret to determining the center of gravity. The center of gravity is the point in an object at which its mass is in equilibrium. Where this point is depends on the object’s shape and weight dis
tribution, and you can produce some attention-getting creations with this knowledge.
The following four projects are easy to do with items found just about everywhere.
Sneaky Balancer I
Knowing how to lower the center of gravity of an object allows you to produce figures that seemingly defy gravity (or make you seem like a skilled magician). This project demonstrates what happens when two similar cardboard figures have their center of gravity in different positions.
What’s Needed
Scissors
Cardboard, a piece 8½ by 11 inches
Optional:
Sewing thread
What to Do
Cut out the small shape shown in Figure 1 from the piece of cardboard. Follow the dimensions shown. Next, try to balance the head of the figure on your fingertip, as shown in Figure 2. It’s almost impossible to keep it upright without its tipping over.
Next, cut out the figure shown in Figure 3. The only difference is the legs are much longer. Try to balance this larger figure on your hand. It’s easy now, because the center of gravity is below your finger. See Figure 4. You should be able to walk around the room and the figure will not fall.
FIGURE 1
FIGURE 2
Going Further
To demonstrate how acrobats keep their balance, cut a small slit in the head of the figure. See Figure 5.
Then, tie a length of thread from a chair to a lower object, such as another chair or table, and set the figure on the thread. The figure should rest on the thread in its slit and, with a slight push, slide across without falling. See Figure 6.
FIGURE 3
FIGURE 4
FIGURE 5
FIGURE 6
Sneaky Balancer II
This sneaky balancer can rest horizontally on the tip of a paper clip and will surely astonish onlookers.
What’s Needed
Scissors
Cardboard
Paper clip
What to Do
Cut out the figure shown in Figure 1 from the piece of cardboard. Be sure to include the spiked hair, with a long center spike. Try to adhere to the dimensions shown but, if desired, you can produce a larger or smaller figure as long as you keep the arm and body lengths in proportion.
FIGURE 1
FIGURE 2
Bend the figure’s arms down at the shoulder and elbows. See Figure 2.
Next, bend a paper clip, as shown in Figure 3, so one end stands up vertically.
Last, place the figure on the paper clip with the spiked hair resting on the tip. If necessary, bend the arms down so it won’t fall. The figure should balance on the tip of the paper clip. You should be able to carefully push its legs to the right or left and it will stay aloft. See Figure 4.
FIGURE 3
FIGURE 4
Sneaky Balancer III
What’s Needed
Scissors
Cardboard, 8½ by 11 inches
What to Do
Cut out the shape shown in Figure 1 from the cardboard. Be careful to follow the dimensions shown.
You should be able to easily balance the figure on the tip of your finger, elbow, or nose, because its center of gravity is at the large circular area. See Figure 2.
You can create similar figures and, using paper clips or coins secured with tape, add weight to an area near the bottom section of the figure so it balances effortlessly.
FIGURE 1
FIGURE 2
Part II
Sneaky Science Projects
Science is sometimes difficult to understand but you can demonstrate its principles with common household items. Paper and cardboard from product packaging, paper clips, aluminum foil, and paper cups can be quickly transformed into practical science projects.
If you’re curious about the sneaky adaptation possibilities of more complex household devices, you’re in the right place. People frequently throw away damaged gadgets and toys without realizing they can serve unintended purposes. You’ll learn sneaky sources for wire and how to connect things. You’ll see how to make a Frisbee disc with ordinary paper, clever center-of-gravity balancing designs, a handheld and a palm-sized cardboard boomerang, a sneaky periscope from a cookie box, and much more.
All the projects have been tested and can be made safely in no time. If you want to practice recycling and learn high-tech resourcefulness, the following projects will provide plenty of chances for fun product reuse applications.
Sneaky Periscope
One of the most useful devices you can build is a periscope, which allows you to take sneak peeks around corners or over fences without being seen. A periscope uses two mirrors positioned so light is reflected from the top mirror down to the lower mirror.
This project illustrates how to construct your own sneaky periscope in no time using an ordinary food carton and a couple of mirrors or watch batteries.
What’s Needed
Two small mirrors or watch batteries
Long cardboard food box, typically 8 inches long and 1 inch wide
Transparent tape
Scissors
What to Do
First, unfold the food container box and lay it flat as shown in Figure 1.
Next, cut two 1 -inch square holes in the box as shown in Figure 2. Cut one hole close to the top end of section 1 and cut the other hole near the bottom edge of section 3.
At the opposite ends of the holes in sections 1 and 3, fold over the flaps to form triangles and secure them to the box with tape. See Figure 3. These flaps will act as mirror mounts.
Position the mirrors (or watch batteries) on the triangular flaps so they are leaning toward the center of the cardboard and secure them with tape as shown in Figure 4.
Last, fold the box so it’s back to its original form. Secure the seams and ends with tape. See Figure 5.
When you hold the periscope upright, as shown in Figure 6, you will be able to see over tall obstructions without being seen. When you hold the periscope sideways, you will be able to see around corners.
FIGURE 1
FIGURE 2
FIGURE 3
FIGURE 4
FIGURE 5
FIGURE 6
Sneaky Origami
Paper folding is fun but you can enhance your enjoyment by making the following sneaky origami designs that include motion action using everyday things.
Sneaky Head-Bobbing Bird
What’s Needed
Scissors
Paper
Pencil
What to Do
Cut the paper into a square and fold/unfold both the diagonals, as shown in Figure 1. Fold over the top left and right corners to the center. See Figure 2.
FIGURE 1
FIGURE 2
Then, fold over the lower left and right corners toward the center as shown in Figure 3. Fold up the bottom point to the center line to form a tail and fold the top corner toward the back of the figure to make the head, as shown in Figures 4 and 5.
Next, fold the figure in half vertically along the center toward the tail. This will bend the tail and head outward as shown in Figure 6. Draw eyes and a beak on the figure as desired.
Last, with the sneaky bird standing upright, push down on the center of the tail. The head should move downward. See Figure 7.
FIGURE 3
FIGURE 4
FIGURE 5
FIGURE 6
FIGURE 7
Sneaky Mouth Flapper
What’s Needed
Scissors
Paper
Pencil
What to Do
Cut the paper into a square, as shown in Figure 1. Next, fold and unfold the square on both the diagonals. Fold over the lower left and right corners to the center. See Figure 2.
Then, fold over the upper left and right corners toward the center, as shown in Figure 3. Fold up the bottom half of the figure along the center crease. See Figure 4. Fold down the top front corner to the bottom of the figure, as shown in Figure 5.
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