Sports can be a great way to demonstrate different principles of physics. Visit the links below and try the activities to discover the science behind various sports.
Check out this link :http://espn.go.com/espn/sportscience/index
READY SET LIFTOFF
Ski jumping converts gravitational potential energy to kinetic energy using torque. The objective is to launch a human projectile as far as possible. By manipulating a track, you can discover how changing the launch angle and torque will change the direction and duration of flight.
• 1 meter (3.3′) of Styrofoam pipe insulation, cut lengthwise
• marble or small steel ball
• 8 to 10 thick books or bricks or a chair
• masking tape
• tape measure
• paper and pencil
1. Start building your “inrun” by piling several books on a table so that they measure about 30 cm (12″) high. Place one end of the pipe insulation right on the edge of the table, and put the other end under one of the books at the top of the stack. Build up several books under the middle of the ramp so that it doesn’t sag or bend. Secure the insulation to the table and books with masking tape, making sure you don’t tape across the track.
2. Place your marble at the top of the ramp. Without pushing, let it roll. Observe the flight path and the place where it first lands on the floor. Repeat this step four more times so that you can get a consistent reading. Remember to start from the same place each time. Measure and record this distance under the heading “flat track”, and draw the shape of the marble’s flight path.
3. Remove the books holding the middle of the ramp and adjust it so that it curves down to the table and runs flat along the table for about 20 cm (8″) before it reaches the end. Make sure that the end of the ramp still lines up exactly with the edge of the table and once again secure it with masking tape.
4. Using the same marble as before, test the ramp again. Remember to start from the same place. Record the distance under the heading “curved track” and again draw the flight path of the marble.
5. Repeat step 4 but this time add a book to the end of the ramp so that instead of lying flat on the table, the ramp curves down and back up a bit. Record your measurements under the heading “U-shaped/one book” and draw this flight path.
FRISBEE…FLYING WITH TORQUE
The torque of the Frisbee forces air down (action) and the air forces the Frisbee upward (reaction). The air is deflected downward by the Frisbee’s tilt, or angle of attack. Spinning the Frisbee when it is thrown, or giving it angular momentum, provides it with stability. Angular momentum is a property of any spinning mass. Throwing a Frisbee without any spin allows it to tumble to the ground. The momentum of the spin also gives it orientational stability, allowing the Frisbee to receive a steady lift from the air as it passes through it. The faster the Frisbee spins, the greater its stability. By graphing the results of various tosses you will be able to calculate the average distance you can make a Frisbee fly and discover the best conditions for distance flying.
• Frisbees of different sizes and thicknesses
• Tape measure
1. Divide your class into equal teams. Take turns throwing the Frisbee.
2. Measure the distance from where you began to toss the Frisbee to where it hits the ground. Record your distances in a log.
3. After everyone has recorded the distances of a few tries, calculate the average distance of your team’s throws.
4. Compare your average to the other teams. Record the averages in your log and create a graph to represent your data.
Rubber Band Shoot Out
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Who would have thought that a simple rubber band to be a great science experiment and great fun for kids.
• Rubber bands (variety)
• Ruler (inches and centimeters)
• Yard stick with metric measurement
Decide the location you will shoot your rubber bands from. Mark this location as your starting point. Make a guess how far your rubber band will fly if it is pulled back 6 inches. Place the rubber band over the end of the ruler and pull it back so it stretches to the 6 inch mark.
Hold the ruler so the front just reaches the location you marked as your starting point. Let the rubber band fly. Place a marker on the ground where you rubber band lit when it first touched the ground.
Often rubber bands will bounce along the ground before they come to rest. You want to mark the original spot that the rubber band hit the ground. Now measure the distance your rubber band flew. How close were you to your guess?
Keep notes on this experiment. Next, make a guess how far your rubber band will fly if stretched 10 inches. Give it a try. Were you close with your guess?
Try these other kids science experiments with rubber bands. Use different lengths and thicknesses of rubber bands to see how far the rubber bands will fly. Get a friend to do the experiments and use metric measurements for the distance instead of feet and inches. Does the color of a rubber band affect how far it flies? If a rubber band gets wet will it fly as far as a dry rubber band?
Science behind the experiment The rubber in rubber bands is bound together by thousands of long chains of molecules that are coiled together something like a net. When you pull a rubber band the molecules uncoil and align themselves closer together as they straighten out. When you release the rubber band the molecules that have been straightened recoil back into their original position. The molecules returning to their original position causes the rubber band to fly through the air.
When a person bats they’re (usually) seeking to maximize the force of contact between the ball and the bat through efficient use of their body. Since the person is swinging, the action is akin to pulling a lever. That is, something is (approximately) rotating about a point or axis. There are a lot of variables that go into this, but roughly the force of contact is related to a torque. sometimes called moment of force, created by the motion of the arms and bat (as well as a portion of the torso). The strength of this force partly depends on the distance, the contact point is from the axis of rotation.
Try this. Get some soft rag balls, plastic bats, tennis rackets, and plastic golf clubs. We will be testing our torque by hitting the ball and measuring the distance that the ball travels. Cool and fun way to educate our kids about torque. Torque is a combination of force applied at a point with the right angle for maximum distance.