November 2014

Toothpick Star Table Trick (11/5/14)

MATERIALS:

  • Toothpicks
  • Water

INSTRUCTIONS:

  1. Bend five toothpicks in half without completely tearing them apart. Each toothpick should look like a “V”.
  2. Arrange the toothpicks in a circle on a flat surface (or plate) with the points of the toothpicks touching each other. Try to arrange the toothpicks as symmetrically as possible for the best result.
  3. Slowly drop a small amount of water into the center of the toothpick arrangement. Watch in amazement as the ends of each toothpick meet to form a star!

HOW DOES IT WORK?

Toothpicks are made of dry wood which is made up of porous fibers that easily absorb water, much like a sponge. When we break the toothpicks in the middle, the wood fragments inside compress. Once we add water to the center circle of the star, capillary action causes the water to be absorbed into the toothpicks. The water moves inside the toothpick from the starting point of the break and moves along the length to the pointed tips, causing the toothpicks to glide as they straighten.

NOW TRY THIS!

  • What happens if you add vinegar or soap?
  • Does this work with other shapes such as a pentagon?
  • Does the temperature of the water make a difference?

Singing Water Glasses

MATERIALS:

  • Water
  • Water Glasses

INSTRUCTIONS:

  1. Fill the glass about half-full with water
  2. You’ll need a little moisture to help, so dip your finger into the water.
  3. Place your clean, moist finger on the rim of the glass, press down slightly, and rub it all the way around the rim without stopping. Keep going in a circular motion along the lip of the glass while maintaining the pressure.
  4. Remember: Several things have to be just right for a tone to be produced: pressure, moisture, glass type, etc.

HOW DOES IT WORK?

As you rub your finger on the rim of the glass, your finger sticks to the glass and then slides. This action occurs in short lengths and creates a vibration inside the glass which makes a sound. As soon as the first vibrations are made, the glass resonates. That means you’re causing the crystals in the glass to vibrate together and create one clear tone.

NOW TRY THIS!

  • Does changing the amount of water make a difference?
  • If you change your finger pressure, what happens?
  • Does water temperature make a difference?