The Case of the Crooked Carnival (8 page)

Y
ou’re taking a pleasant stroll along the wetland path. Suddenly—aliens invade! Send a secret message to warn your partner! Here’s how:

MATERIALS

• 3 index cards

• scissors

• pencil

• eraser

PROCEDURE

1.
Cut out five or six rectangles here and there from an index card. Make a second index card just like it. (These are your master code keys. They should look exactly alike. You keep one; your partner gets the other.)

2.
To write a message, place your master copy over a blank index card. Write your code through the holes onto the blank index card, using one word per rectangle.

3.
Uncover the bottom index card. You should have five or six words on the card. Now fill in the rest of the note by including those words in sentences. (Erase and start over if it doesn’t sound natural.)

4.
Send only the bottom index card to your partner. Keep the master code key.

5.
To read, your partner places his/her master copy over the index card. The code words will show through the rectangles to reveal the secret message:
Nature Headquarters, six tonight!

H
ave you ever wanted to create your own little world? Be “master of the universe,” so to speak? In this activity, you can create your own little world by building a terrarium. A terrarium is a miniature ecosystem (a place where plants and animals interact with one another and with their environment, including water, light, soil, and climate). It’s fun and easy to do. Here’s how:

MATERIALS

•  fishbowl or similar clear container—big enough to allow you to easily put your hand through the opening

•  pea-sized gravel, such as the kind used for the bottom of a fish tank

•  large spoon (for scooping charcoal and soil)

•  charcoal, such as the kind used in fish tank filters—find at pet stores

•  potting soil (buy organic
sterilized
soil as it won’t have fungi and molds)

•  measuring cup

•  mixing bowl

•  two to three slow-growing, water-loving plants that won’t grow too big (such as small ferns, nerve plant, false aralia, pink polka-dot plant, pilea, mini African violet, gloxinias, hepaticus, coleuses)

•  paper towels

•  cool stuff like rocks, ceramic frogs, gnomes, ninja warriors … (optional)

•  plastic wrap

•  rubber band

•  scissors

PROCEDURE

1.
Wash the fishbowl with warm soapy water. Rinse and dry completely.

2.
Add gravel to the bottom of the fishbowl until it is ½ inch to ¾ inch deep.

3.
With the spoon, scoop ¼ inch of charcoal over the gravel. Level it out in an even layer.

4.
Pour approximately four cups of soil into the mixing bowl (
not
the fishbowl!) and stir in some water (about
cup). The soil should be damp enough so that it remains in a ball after you squeeze it. If it crumbles, add more water. If water drips out, add more soil.

5.
Spoon in enough of the dampened soil to fill up to
or ½ of the fishbowl.

6.
Decide where you want your plants. For each plant, dig a small hole (don’t go too deep or you’ll hit the charcoal), and then set the plant in the hole. Cover the roots with soil and pat the soil firmly so the plant stays in place. Repeat with your other plants. Don’t be afraid to add more soil, if needed.

7.
Carefully clean the inside of the glass with paper towels.

8.
Add a few small handfuls of water. (Sprinkle it from your hand rather than pouring it in. This is gentler on the plants’ delicate roots.)

9.
Add your cool stuff if you want. Perhaps a ninja warrior hiding behind a fern? Or a ceramic frog sitting on a rock? Up to you.

10.
Cover the opening with plastic wrap and secure with a rubber band. Trim the plastic wrap with scissors if it’s too big.

11.
Set your terrarium in a warm place where it will receive plenty of “indirect” light (not directly in the sun).

12.
Sit back and watch the plants grow, oh you master of the universe, you.

Terrariums need just the right amount of moisture, so they are neither too wet nor too dry. So how do you determine the right amount of moisture? Here’s a hot tip: if, after two days, moisture droplets (called
condensation
) form on the
sides of the glass
and obstruct your view, your terrarium is
too wet.
Remove the plastic wrap for a day or two and let it dry out.

If, after two days, there isn’t any condensation forming on the
underside of the plastic top
, your terrarium is
too dry.
Add a
little
more water and cover it back up.

The moisture content of your terrarium is perfect when water droplets form on the underside of the plastic top, while the glass sides of the fishbowl remain clear. A terrarium with just the right amount of water will only need to be watered every 2–3 months. Also, trim any plants that grow too big.

How Does This Work?

Regular potted plants must be watered frequently because the water turns into a vapor, like cool steam, and escapes into the air. This process is known as evaporation. But because a terrarium’s environment is enclosed, evaporating water cannot escape. So when vapor touches something, like the underside of the plastic, it forms condensation, or moisture droplets. Eventually the condensation drips on the plants like rain. This is called precipitation. A terrarium is just like a real ecosystem with a cycle of: