In the air section you can find how to use science to perform magic tricks based on the sound properties and how to enhance any magic show.
These tricks and ideas can be used in any science projects or just for fun.
If you know any different tricks that would like to share with the other kids, you can contact us and we will make it possible.
Click on the list bellow to find how to perform it.
- What is a sound
- Sound waves
- Sound travel through nothing
- Sound travel through a liquid
- Sound travel through a solid
- Sound speed
- Direction of a sound
- Variations with strings
- Striking sound
- Blowing sound
- Amplifying loudness
- Seashell resonance
What is a sound?
What can cause a sound?
To make to experiment you will need: clothesline (Venetian-blind cord), paper clips (bobby pins)
Step 1: Attach one end of a clothesline or Venetian-blind cord to a doorknob. Measure off about 4 feet of line and rest your foot on the line so that a portion is kept taut. Pluck it.
Step 2: Say "ah-h-h" as you touch the sides of your throat.
Step 3: Place paper clips or bobby pins on a drum (you can make your own drum by encircling a coffee can with wrapping paper). Beat the drum top lightly.
Step 4: Whisper "too" into straws of different lengths.
Step 5: Strike a fork with another utensil and bring it close to your ear.
Step 6: Hold a steel knitting needle or yardstick on the edge of a table. Pull the needle or yardstick upward and let it snap down quickly.
What you will see: In each case, you hear a sound-and you see or feel a movement to and from.
Why: In each of your experiments, you make sound by causing an object to vibrate-to move back and forth or up and down. The number of vibrations per second (known as the frequency) depends on the size, shape and material of the object that is vibrating. Our ears cannot hear sound unless the object vibrates at least 16 times per second and not more than 20,000 times per second. We know, however, that certain insects and birds can hear objects vibrating at a much faster speed. You can summon your dog with a special whistle which your dog can hear but you cannot because it vibrates so fast.
You need: cereal kernel, clothes hanger, rubber band, threads.
Step 1: Attach dry cereal kernels (such as puffed rice) to threads by gluing, sewing or by merely wrapping thread around each kernel.
Step 2: Suspend the threads (close to one another) from a clothes hanger.
Step 3: Hook the hanger onto the back of a chair or shelf so that you need not hold it. Step 4: Stretch a rubber band out from your clenched teeth and pluck the taut rubber band next to (but not touching) the kernel or ball in the center.
What you will see: The vibration of the rubber band causes the ball next to it to move. As the ball moves to and fro, it hits a ball on each side, which in turn hits its neighbors. This continues until the energy is spent. If the rubber band is plucked harder, more balls move. No one ball, however, moves very far.
Why: The experiments gives you an idea of how sound travels from a vibrating object to your ear. When an object vibrates to make sound, the object bumps the small invisible air or solid or liquid particles or molecules next to it on all sides. Before they bounce back, the molecules bounce into other molecules near by. These bump into their own neighbors. Thus, while each molecule moves but slightly, sound may travel great distances.
The molecules of human ear are bumped, our eardrum vibrates, the nerve endings take the vibrations to our brain and there they are converted to sound.