June 2014

Mentos Geysers (6/25/14)

MATERIALS:

  • 2 liter of diet soda
  • 2 jumbo paper clips
  • Roll of Mentos mints
  • Scissors
  • Microwave
  • Eye protection
  • Adult supervision

INSTRUCTIONS:

  1. It is recommended to try this activity outside on your lawn or in an empty parking lot!
  2. Unfold a paper clip so that it is straight, and form a small loop at one end.
  3. Pierce the Mentos with the non-looped end of the paper clip and skewer the mints on top of one another. You should be able to fit 6-10 Mentos on the paper clip. If you are having trouble getting the paper clip through the Mentos, try placing the mints on a plate and microwaving them for 10-15 seconds to soften them.
  4. Bend a small hook at the end of the paper clip so the Mentos don’t fall off!
  5. Unfold another paper clip so that it is straight. This paper clip is going to be the “pin” that holds the Mentos in place until you are ready for action!
  6. Grab an adult to help with this step! Unscrew the cap from the diet soda. Carefully poke a hole through the center of the lid with scissors. Twist and turn your scissors until the hole is large enough for a pea to fit through. If you are having trouble making a hole in the cap, try microwaving the lid for 30-45 seconds to soften the plastic.
  7. Place the cap over the looped end of the Mentos skewer, and slide the other paper clip “pin” through the loop.
  8. Strap on your safety goggles, and make sure you are wearing old clothes! This is going to get messy!
  9. Pour out one-quarter of the diet soda (or you can drink it!).The remaining soda should fall just below the top of the bottle’s label. This step is important because you don’t want the Mentos to react with the soda until you are ready!
  10. Position the soda bottle on the ground so that it does not tip over, and tightly screw on the cap with the Mentos hanging below, making sure the “pin” is secure.
  11. Get ready for some fun! Warn your spectators to stand back. When everyone is at a safe distance from the soda bottle, quickly pull out the pin and run for the hills! Wow, how amazing is that?!

HOW DOES IT WORK? When you pour yourself a glass of soda, have you ever noticed tons of tiny bubbles in your drink? That’s because factories pump carbon dioxide gas into the soda, creating lots of pressure against the bottle. The gas can’t wait to escape the bottle, so when you open it, the gas is released in the form of bubbles! Dropping Mentos into the soda speeds up this process by breaking the surface tension of the liquid and allowing bubbles to form on the surface area of the Mentos. Like a golf ball, Mentos mints are covered with lots of tiny dimples which increases the surface area and allows a ton of carbon dioxide bubbles to form!

NOW TRY THIS!

  • Try dropping different types of candy in diet soda! Can you recreate the gushing geyser with Skittles?
  • Try using different types of sodas. What happens when you use regular soda? Can you use non-caffeinated sodas like Sprite?

Rainbow Milk (6/11/14)

MATERIALS

  • Milk (whole or 2%)
  • Bowl or pan
  • Dishwashing soap
  • Cotton swabs

INSTRUCTIONS

  1. Pour milk into the bowl or pan until it completely covers the bottom. The milk only needs to be about ¼ inch deep.
  2. Add a drop of each of the colors of food coloring to the center of the bowl.
  3. Next, find a cotton swab, and place a drop of dishwashing soap on the cotton swab.
  4. Get ready for the fun part! Dip the soapy end of the cotton swab into the center of the bowl, and hold it there for 10-15 seconds. Remember not to stir! Doesn’t it look like the Fourth of July in a bowl of milk?!

HOW DOES IT WORK?

Milk is mostly made up of water, but it also contains vitamins, minerals, proteins, and fat. The fat found in milk is the key to making rainbow milk! The second key to making rainbow milk is the dishwashing soap! A soap molecule has bipolar characteristics. This means that a tiny soap molecule has two ends: a polar end and a nonpolar end. The polar end (hydrophilic) absolutely loves water, so that end dissolves in the water. The non-polar end (hydrophobic) hates water, so it rushes to find a fat molecule to hang on to. During this crazy race to find a fat molecule partner, the food coloring molecules are pushed and bumped around, giving us an easy way to see this otherwise invisible activity!

NOW TRY THIS!

  • Try using different types of milk that you might find in your fridge. Will skim milk still produce amazing color bursts? Why?
  • Try dipping the soapy end of the cotton swab in different locations of the milk bowl. Do you observe the same effects?