The Case of the Terrible T. Rex by Michele Torrey Read Free Book Online Page A

14. A neutral is 7.
    pH Scale
    1   2   3   4   5   6   7   8   9   10   11   12   13   14
    More Acidic      ←      Neutral      →      More Basic
    The pH scale also answers the questions How acidic and How basic For instance, a substance that scores a 2 on the pH scale is more acidic than a substance that scores a 4 or a 5. Likewise, a substance that scores a 14 on the pH scale is more basic than a substance that scores an 8 or a 9.
    Well, you say, this is all very fascinating, really, but … what’s that got to do with my poor little fish?
    A most excellent question! You see, purple cabbage juice contains a purple pigment called flavin , which acts as a pH indicator . By dipping your paper fish into the cabbage juice, you created pH indicator fish! When mixed with acids, the pH indicator fish turn pink. When mixed with bases, they turn greenish yellow. But if a neutral liquid touches the indicator fish, the color doesn’t change!
    Now all you have to do is compare the color of your fish to the pH chart below. Determine which of the water samples were acids, bases, or neutrals. Were your fish swimming in “clean” or polluted water? Gadzooks! It’s up to you to save the day! There’s no time to lose!

    *For this exercise, we will assume that anything other than a neutral pH indicates polluted water. In nature, this is not always the case.
    For a full color pH scale, visit http://commons.wikimedia.org/wiki/File:PH_scale.png
    BE A REAL-LIFE HERO!
    Face it. Fish and other aquatic wildlife depend on us to keep their habitat clean. Why not be a real-life hero and help out your local waterway? Your efforts could save hundreds, maybe thousands, of lives! Here are some resources to get you started:
    •    www.kidsforsavingearth.org/waterpollution/waterpollution.htm
    •    www.epa.gov/kids/water.htm
    •    www.epa.gov/adopt/earthday/index.html
    •    www.kiddyhouse.com/Themes/Environ/Water.html
    •    www.oceansidecleanwaterprogram.org/kids.asp

I n 1979, thirteen-year-old India Wood saw a bone sticking out of some layers of rock in Colorado. Being an amateur fossil hunter, India carefully excavated the bone. She identified it as the pelvic bone of an Allosaurus , a carnivorous dinosaur. Over the next several years, and with some help from the Denver Museum of Nature & Science, India excavated the entire Allosaurus skeleton (now on display at the museum). Way to go, India!
    In this activity, not only will you create your own cool sedimentary layers, but you’ll also practice digging for dinosaurs, just like India did!
    MATERIALS
    •   2-quart container with tight lid

    •   playground sand
    •   measuring spoons
    •   food coloring: green, yellow, blue, and red

    •   small plastic aquarium or similar clear container, approximately 11 by 7 by 8 inches (you can do an Internet search for “Critter Keeper”)

    •   8 to 10 small “fossils,” such as shells, chicken bones (make sure they're clean!), or plastic dinosaurs

    •   small, clean paintbrush

    PROCEDURE

    1.    Fill the 2-quart container about ⅔ full of sand.
    2.    Add 1½ teaspoons of green food coloring to the sand.
    3.    Replace the lid on the container and shake the sand for about 1 minute until the sand turns green.
    4.    Pour half of the green sand into the plastic aquarium. Place some of your fossils here and there on the sand, and then pour in the remaining green sand.

    5.    Repeat steps 1–4 with each of the yellow, blue, and red food colorings.

    6.    Record your observations. (Can you see the different stratification layers?)
    7.    Using the paintbrush, go on a dig. Carefully brush away the sand until you— gasp! —stumble upon a fossil! Continue to brush away the excess sand until the fossil is completely exposed. (If you need to scoop out some sand from your aquarium, go ahead. Just be sure you don’t disturb