After asking Rosa to list the ingredients in a tres leche cake, Drake and Nell stepped outside to look for additional clues. Drake jotted his observations in his lab notebook:
Fruit tree in front yard.
Ice cream truck—music in the air.
Giant antenna down the street.
“Hmm,” said Drake. “I don’t remember seeing that antenna last week at the fiesta.”
“Sí—that’s because our neighbor just put it up a couple of days ago.”
“A new antenna …” mused Drake. He cocked his eyebrow and glanced at Nell. “Are you thinking what I’m thinking, Scientist Nell?”
“Quite possibly, Detective Doyle. But there’s only one way to find out.”
“Back to the lab!” cried Drake. “For analysis!”
“Expect our report ASAP, Ms. Alvarez,” said Nell as she climbed on her bike.
“Meanwhile,” said Drake, climbing on his bike as well, “stay out of the kitchen.”
Rosa waved good-bye with her spatula. “Hurry! The guests arrive in two hours! We must have cake!”
Back at the lab, Drake and Nell wasted no time. They pulled a book off the shelf and turned to the correct section: “Loco Oven Analysis: What to Do When Your Oven Has a Code Name, Laughs Like the Dickens, and Your Fiesta Becomes a Fiasco.”
After Nell read the section aloud, Drake formulated a hypothesis. He said, “I believe what’s happening to Rosa’s oven is …”
Nell listened and nodded. “Agreed. Let’s test our hypothesis. Meanwhile, maybe we could ask for your mother’s help.”
So, with Mrs. Doyle on board (she’d said, “No problemo” when asked for her help), Drake and Nell tested their hypothesis. They plugged this into that. They dialed this knob. They twirled that dial.
Then they headed back to Rosa’s neighborhood and conducted a quick stakeout. It took only 2.5 minutes of standing outside the neighbor’s window before they had their answer. And not just any answer. The right answer.
Analysis complete, Drake and Nell hurried back to Rosa’s. “We’ve solved the mystery, Ms. Alvarez,” said Drake, as they entered the kitchen.
“But what about my cake?” Rosa asked. “Everyone will be coming soon for the surprise. There’s not enough time now to bake a cake.”
“First things first,” said Drake. “Scientist Nell?”
“Thank you, Detective Doyle.” Nell began to pace. “Are you aware, Ms. Alvarez, that there are radio waves everywhere? For instance, there are radio waves bouncing off this cake batter, off my arm, through the air, and even through outer space.”
Rosa looked puzzled. “If that is true, then why can’t we hear them?”
“Excellent question,” said Nell. “In order to hear speech or music across radio waves, two things must occur. Detective Doyle?”
“Ah, yes, two things.” Drake pushed his glasses up with his finger. “First, someone must transmit the speech or music. Second, someone must be able to receive the transmission. There is speech and music being transmitted all the time through radio waves. But you can’t hear anything unless you receive it. Case in point—” Drake walked over to a radio sitting on the counter and flipped it on.
“. . . para bailar la bamba …”
“Ah, one of my favorites.” Drake tapped his foot. “You see, Ms. Alvarez, your radio is a receiver, enabling us to hear the transmission.”
“Now, all of this brings up an important question.” Nell stopped pacing, her hands clasped behind her back. “Why don’t we hear all the radio stations at once? With all the voices and all the music in one big jumble?”
“Excellent question, Scientist Nell,” Drake answered. “Because radio operators transmit on a certain frequency. When you turn the knob on a radio, you are dialing in different frequencies.” Drake twirled the dial of the radio, and as he did, the radio stations changed.
“There are thousands of frequencies,” said Nell, “all with different-size wavelengths.”
“But,” said Rosa, glancing at her watch, “my mother … the cake … the fiesta … and what does any of this have to do with my oven?”
“Ah,” said Drake. “Now we come to the heart of the matter. You see, in order for something to receive a particular radio transmission, it must first be resonant on that frequency. Let’s say there are A to Z frequencies. If someone transmits on H frequency, we must tune into H frequency in order to hear him or her. Now, we noted that your oven had one element that was broken—”
“And one that was not,” said Nell. “Very simply, the two elements canceled each other out. In doing so, they created resonance on a particular radio frequency.”
“Plus,” added Drake, “the oven acted as a nice speaker box. Quite handy, really.”
“So we were hearing a radio?” asked Rosa.
“Not just any radio,” replied Nell, “but a ham radio. Your neighbor’s ham radio, to be precise. His signal was very strong because he was transmitting from just down the street.”
“You see, Ms. Alvarez,” said Drake, “ham radio operators are amateur radio buffs. They transmit and receive radio signals from all over the world. We suspected there was a ham radio operator because of the size of the antenna. To confirm our suspicions, we listened outside your neighbor’s window.”
“Sure enough,” said Nell. “His was the same voice we heard coming through the oven—”
“Same laugh,” added Drake.
“With the same call sign beginning with KA7,” said Nell. “A simple case, really.”
“A piece of cake, as they say,” said Drake.
“But,” said Rosa, “what about when the oven said, ‘You’re next, little lady’?”
“Just his granddaughter, taking her turn at the radio,” answered Nell.
“Our recommendation?” said Drake. “Fix the oven element. Should take care of the problem.”
“Well, gracias.” Rosa sighed, her smile still, sadly, a little droopy. “I just wish I’d had time to bake a tres leche cake. Now it is too late, and everyone is due in ten minutes.”
Drake cocked an eyebrow. “Ten minutes, you say? Then there’s no time to lose.” He whipped out a walkie-talkie from his lab-coat pocket. “Calling FF, calling FF, this is Muffin Man, over.”
“You see, Ms. Alvarez,” explained Nell, “a walkie-talkie is a two-way radio. It can transmit as well as receive.”
The walkie-talkie crackled to life. It was Kate Doyle’s voice. “Fab Foods here. Is it time?”
“Affirmative,” replied Drake. “Over and out.”
Five seconds later, the doorbell rang.
It was Mrs. Doyle. “Yoo-hoo! ¡Hola! Fab Foods calling with a tres leche cake and decorations for a fine fiesta!”
At that very instant, a scientific miracle occurred. Rosa Alvarez’s smile turned right side up. “You have saved the day!” she cried, suddenly looking quite cheery.
And as Mrs. Doyle bustled into the kitchen, Rosa turned to Drake and Nell. “¡Gracias, mis amigos! How can I ever repay you?”
“A piece of cake, perhaps?” said Drake.
Nell nodded. “A piece of cake, indeed.”
That night, Drake wrote in his lab notebook:
Case of the loco oven solved.
Broken oven + ham radio
transmissions = talking oven.
Fiesta a smashing success.
Danced the salsa and ate tres leche
cake until I achieved maximum capacity.
Paid in full.
Contents
Your Own Lab
Science by the Book:
The Scientific Method
Werewolf Case at Midnight:
Hot Air
Those Poor Little Fish:
pH and Water Pollution
Digging for Dinosaurs:
Paleontology and Startification
Hamming It Up with Morse Code:
Morse Code and Ham Radio
One day while hiking, you stumble across a suspiciously dirty stream. You
r mission? Record your observations and collect some water samples for analysis. You reach for your specimen jars, only to realize you don’t have any! Nor do you have a lab notebook! Or a lab, for that matter! Horrors! Next time, be prepared. Here’s how:
1. Set up a card table and chair in your basement, your attic, or your bedroom—wherever there’s room. Hang up a sign that reads LABORATORY.
2. Stock your lab with odds and ends—clean jars with lids, tape, string, fishing line, batteries, wire, funnels, clean paintbrushes—anything you think might come in handy.
3. Of course, every top-notch scientist must wear a lab coat. A white button-down shirt is perfect (ask first!). Using a permanent marker, write your name on the shirt.
4. Lastly, where would you be without a lab notebook to scribble in? Spiral or bound notebooks work great. Sharpen your pencil, write your name in your notebook, and voila! You can now investigate that stream!
A good lab notebook contains:
1) Experiment title
2) Method (what you plan to do)
3) Hypothesis (what you think will happen)
4) Procedure (what you did)
5) Observations (what you saw)
6) Results (what actually happened)
Good Science Tip:
Whenever you collect a water sample from your local stream, river, or lake, label the sample container with the location, date, and time. Then, in your notebook, record any observations. For example, what color is the water? Are there any odors? Is the bank muddy, rocky, or sandy? Are there plants? Are there any pipes nearby? Cover and store your sample in the refrigerator and test within twenty-four hours.
While there’s no single book that gives all of the answers to every science mystery (except for Drake’s book, of course!), scientists are still on the same page when it comes to the scientific method.
Step one: scientists observe. They examine, they prod, they peer, and they poke. They write it all down in their lab notebooks.
Step two: based on their observations, scientists develop a hypothesis, which, if you recall, is a scientist’s best guess as to what is really happening or what will happen. Remember Drake and Nell and the floating tent? Likely Nell’s hypothesis sounded something like this: “Based on our observations, I believe the tent floated off because it was pitched over a fumarole. I believe the fumarole filled the tent with hot air, making it behave like a hot air balloon.”
Step three: scientists test their hypothesis. (After all, what if the hypothesis is wrong? What if there really are werewolves? Gadzooks!) In testing their hypothesis, scientists follow a procedure. In the following experiments and activities, you will also follow a procedure. It is important to read through the instructions and set out all the needed materials before beginning the experiment. So sharpen your pencils, open your lab notebooks, and let’s get started.
Did You Know?
Want to know more about paleontology? How about fumaroles, water pollution, or ham radios? While the Internet provides many handy and excellent resources, use caution. There is a lot of mis-information on the Internet, too. Why? Because anyone can post anything on the Internet, and no one is required to be correct. So, when you’re looking for answers (and not just any answers, but the right answers), go to your local library. There you will find books written by experts. Having trouble finding just the right book? No problem. Just ask a reference librarian; they’re there to help. After all, they’re experts, too!
Imagine it. You’re a top-notch scientist, assigned to a baffling werewolf case at midnight on Waxberry Hill. Just as the howling begins and your scalp crawls with terror, the tent expands and floats off into the night. Are werewolves to blame, or is there a more obvious solution? As a top-notch scientist, it’s your job to find out.…
MATERIALS
• thin plastic dry-cleaner bag (this is the tent)
Note: The thinner and larger the bag, the better. Try evening gown–size dry-cleaner bags—they are about five-and-a-half feet long.
• 4 large paper clips
• lightweight fishing line (this is the leash, to keep your tent from flying away!)
• hair dryer
(CAUTION: Look over your shoulder now and then, just in case a werewolf is lurking. Don’t let their howling unnerve you …)
PROCEDURE
This activity works best outside on a cool day or in the coolest part of the day. Do not do this activity if there is a breeze.
1. Reduce the size of the opening of the plastic bag (tent) so that it will act like the mouth of a hot air balloon. To do so, gather together small sections of the opening and firmly secure each section with a paper clip. When finished, the mouth of the plastic bag (tent) should be about twice the size of your fist.
2. Tie a long piece of fishing line to one of the paper clips so that your bag (tent) is retrievable.
3. Hold on to the opening of the plastic bag (tent) with one hand. Insert the hair dryer into the opening and turn it on. (Heat should be on high. Be careful that you do not burn yourself or melt the bag.)
4. Once the bag (tent) is filled with hot air, turn off the hair dryer, hold on to the loose end of the fishing line, and release the bag (tent).
5. Watch in amazement as the bag (tent) floats up, up, and away!
6. Now determine what caused the bag (tent) to float. Werewolves? Hot air? Hmm … jot your conclusions in your lab notebook.
How does this work?
Air is composed of molecules. When air is cold, the molecules are close together and vibrate very little, making cold air dense and heavy.
In hot air, however, the molecules vibrate quickly, bumping into one another like popping corn. Because each molecule needs more space to move, hot air expands, making hot air lighter and less dense than cold air.
Conclusion? Hot air tents are lighter than the surrounding cold air environment, so they float up, up, and away! (FYI: Werewolves, besides being shifty and dangerous creatures, are quite dense and therefore must stay on the ground.)
It’s tragic, quite tragic indeed. The water is polluted. The fish are counting on you to save the day! In this activity, you will test the pH of various water samples, just like Nell did. You will determine which water is safe for the fish and which water needs to be cleaned up, pronto!
MATERIALS
• 4 large baby-food jars with lids
• masking tape
• permanent marker
• measuring spoons
• tap water
• white vinegar
• baking soda
• water from a local river, stream, or lake
• purple cabbage
• pitcher
• measuring cup
• white coffee filters
• coffee strainer
• 1-quart jar with lid
• pencil
• scissors
• tweezers
• 2 clean, dry plates
PROCEDURE
1. Collect and prepare four water samples for testing. Prepare each sample as follows (using the tape and marker, label the jars clearly with numbers 1 through 4, and replace the lids as you go):
a) Jar #1: fill with tap water to about ¼ inch from the top.
b) Jar #2: pour in 1 tablespoon of white vinegar, then fill with tap water to about ¼ inch from the top.
c) Jar #3: fill halfway with tap water, add 1 teaspoon of baking soda, replace lid, and shake until dissolved. Finish filling with tap water to about ¼ inch from the top.
d) Jar #4: take a sample from a local river, stream, or lake. (See “Good Science Tip” on page 69.) Fill the jar to ¼ inch from the top.
2. Ask an adult to dice about 3 cups of cabbage. Place the cabbage in a pitcher and ask an adult to pour approximately 1½ cups of boiling water over the cabbage, enough to cover it completely. Let it soak for 30 minutes. (Note: cabbage juice can stain, so wear a lab coat!)
3. Place one coffee filter into the coffee strainer. Over a sink, po
ur the cabbage juice through the coffee filter/strainer into the 1-quart jar. (Be careful that clumps of cabbage don’t fall—SPLAT!—into the strainer and stain your clothes!)
4. With the lid off the jar, let the juice cool completely. Once cool, replace the lid. Using a tape and marker, label the jar “Cabbage Juice,” and date it. (NOTE: keep it refrigerated and discard after twenty-four hours.)
5. Draw some fish on white coffee filters. Each fish should be about 2 inches long. You’ll need at least four fish, but make extra just in case. (Topnotch scientists are always prepared.) Cut out the fish with scissors.
6. Using the tweezers, dunk one fish completely into the cabbage juice, and then place the wet fish on a plate to dry. Repeat with each fish. Allow fish to dry thoroughly.
7. Using a pencil, now label your four (dry) fish “#1,” “#2,” “#3,” and “#4.”
8. Again using the tweezers, dip the #1 fish into the #1 water sample. Lay the wet fish on another clean plate. Dip the #2 fish into the #2 water sample, and so on.
9. Important: record your results while the fish are still wet.
How Does This Work? (Reading the Results)
Scientists created the pH scale as a measurement of whether a substance is an acid or a base. The pH scale is numbered from 1 to 14. Acids range from 1 to 6. Bases range from 8 to 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.
Case of the Terrible T. Rex Page 4