“Agreed,” I said. “We’re going to be disgusting.”
“Vile,” added Phoenix, standing directly to my left.
Avery, who was in front of Phoenix, gave a little twirl. Her short blonde braids twirled, too. “And sickening.”
“Don’t forget foul,” said Julia from the front.
“The most gross, disgusting, vile, sickening, and foul ever,” called out Jeremy from Birdie’s right.
“Yeah!” shouted Memito and Elijah, who stood next to Jeremy.
“You’re ready?” asked Ms. Daly.
“Definitely!” I said, pumping my fist into the air.
On the other side of the gym, there was a spooky cakewalk. Paper pumpkins had been cut out and taped to the floor in the gym for the spooky cakewalk path. Parents and kids were walking around the path while a volunteer dressed in an apple costume played “Monster Mash.” But while our demo was going on, the apple stopped the cakewalk so everyone could watch.
I was so excited.
Ms. Daly cleared her throat and grabbed the microphone. “Are you ready for the Vomiting Pumpkins demo?” she asked.
The audience cheered. She pointed to our two tables.
“These pumpkins ate way too much candy last night, and now they are sick to their stomachs,” said Ms. Daly, “so we’re going to see what happens when you eat too much candy.”
The audience cheered even louder.
“Okay, my teams onstage are now going to dump in their hydrogen peroxide,” said Ms. Daly.
Jeremy grabbed a container of pre-measured hydrogen peroxide and poured it into a larger empty beaker. So did Julia.
“We’re using thirty-five percent peroxide so it’s more concentrated,” continued Ms. Daly. “What you have at home is three to six percent. Now we’re pouring in one cup of dish soap. And we decided that we wanted the vomit to be green, so we’re going to put in food coloring.”
Stepping next to me, Memito squeezed in some green food coloring from a small bottle.
“More more more!” I called out. “You can’t have too much.”
“That’s right,” said Ms. Daly. “We’re looking for a beautiful homogenous mixture.” I knew that meant that everything should be mixed together. “Now it’s time to stir it up,” continued Ms. Daly.
Avery and I picked up our beakers and swooshed them until they were all stirred. Some of the green liquid poured over the top and dribbled on my fingers. Luckily my fingers were safe because I was wearing my lab gloves (of course).
“Okay, I’ll take those from you now.” Ms. Daly placed my beaker in one of the jack-o’-lanterns. “It’s important to put safety first. Always do science with a trained adult,” said Ms. Daly. “I’m angling the beakers a bit just so we get some projectile vomiting.”
I grinned as she put the awesomely yucky green mixture into the center of our pumpkin.
“Great job so far, everyone,” exclaimed Ms. Daly as she finished placing Avery’s beaker in her pumpkin. “What do you think, audience?” There were loud cheers. I could hear my dad whistling and see my mom and Liam wildly waving.
“One of the beakers moved!” Liam frantically pointed.
“That’s okay,” Ms. Daly assured him. “We’re good. But that was a good observation. I’m glad you’re on top of it. You’re going to be a good scientist.”
“Yay!” cried out Liam.
“Now I’m going to add the catalyst,” said Ms. Daly. “A catalyst is sort of special, because it speeds up a chemical reaction. This catalyst is called potassium iodide.”
I couldn’t help but clap my hands. Catalysts are the best! I couldn’t wait.
“Hopefully we’ll see some vomit real soon,” said Ms. Daly.
“Oh, yes!” I cried.
She started with Julia’s pumpkin. After Ms. Daly added the catalyst to the beaker in the pumpkin, Julia quickly put the top back onto her jack-o’-lantern.
“Can you see it?” asked Ms. Daly. “Is it coming?”
“Oh my goodness! Yes,” I shrieked.
Next she dumped the catalyst into my pumpkin.
“It’s gross,” yelled Memito and Elijah.
Foamy-looking sludge oozed out of the pumpkins’ mouths.
“I love it! I love it!” I yelled.
“It’s nice and disgusting,” said Jeremy.
“It’s definitely vile,” said Phoenix.
“And sickening,” sang out Julia, while Avery made a silly face.
“Can you see the heat that’s coming off there?” asked Ms. Daly.
“Tons of it,” said Elijah.
“It’s an exothermic reaction,” explained Ms. Daly. “So actually what happens is we use our catalyst to break down the hydrogen peroxide into oxygen and water. When it decomposes, the oxygen gas is trapped in the soap bubbles, which shoot out of the pumpkin in the form of vomit. It’s a very hot reaction.”
“That’s so awesome,” gushed some kids in the front row.
“That’s science for you!” I shouted.
* * *
Later, Liam dragged Dad to the haunted bounce house, while Mom went to grab some hot cider. Birdie and I wound our way through the fair, buying candy apples, popcorn, and way too many other treats. We met up with Phoenix and Avery at the photo booth where we tried on silly hats, mustaches, and wigs.
Just as I was trying on a rainbow wig, Jeremy, Elijah, and Memito showed up. “Want to get in the photo?” I asked.
“Sure,” said Elijah.
Jeremy and Memito both nodded. After they put on stuff to make them look like ridiculous scarecrows, we all laughed because Memito had so many lollipops jammed in his pockets.
“You’re like a scarecrow that’s stuffed with candy, dude,” said Elijah.
“I can’t help it,” said Memito with a shrug. “I went to the lollipop pull and won.”
“Everyone wins there,” said Birdie, smiling.
“Speaking of winning,” said Memito, pointing to the back of the gym. “Want to try and win something delicious at the cakewalk?”
“Oh yeah!” Jeremy rubbed his hands together. “And we should all do it together, at the same time.”
“Awesome idea,” said Elijah.
Birdie’s eyes lit up. “That way we’ll have a much better chance of winning.”
“Plus, we can split the cake,” suggested Phoenix.
“Yes,” I shouted. “I love that idea!”
“Me too.” Memito grinned and patted his stomach. “Especially chocolate cake.”
“Chocolate is the best,” I said. “But I think we should all do the cakewalk in costume.”
“That might be a little scary,” admitted Phoenix.
“That’s all right,” I said.
“Let’s go,” said Jeremy. “Ready, set, you bet.”
And we all raced off to the gym together, screaming “boo” all the way.
MAGNETIC SLIME
Materials:
½ cup high-quality craft glue
4 tablespoons iron oxide powder
¼ cup saline solution
1 medium bowl
1 plastic spatula
1 neodymium bar magnet
Protocol:
Put on your safety goggles.
Pour glue into a medium bowl.
Have an adult help add the iron oxide powder to the glue.
CAUTION: Do not breathe this in. Go outside to measure if you tend to spill things.
Stir the glue and powder until they’re mixed together well.
Add saline solution to the mixture in the medium bowl.
Stir the glue mixture until all of the saline solution has been absorbed.
Allow the slime to sit for at least 3 minutes.
Wearing gloves, use your hands to knead the slime into a workable sphere.
PRO TIP: Add a few drops of saline solution to your gloves to minimize the stickiness.
Use the neodymium magnet to play with the Magnetic Slime.
CAUTION: Watch your fingers if you have two magnets. You can easily pinch your fingers between these super-strong magnets.
How It Works:
When we add the iron oxide powder directly to the glue, we see the adhesion forces at work. These forces only happen when one molecule has a strong attraction to a different molecule. Stirring the two chemicals together allows for the iron oxide to wiggle itself into the pockets of the polyvinyl acetate (glue). The cross-linked polymer forms when the glue and borate (saline) ions alternate, this time creating a creepy black ball of slime.
We added iron oxide to our slime because it is an extremely dense chemical that is magnetic at room temperature. This means that we can spike our slime with the black iron powder in order to give our gooey substance some magnetic properties. Copper and nickel are two other metals that do the same thing. In order to see the magnetic properties of iron, we have to use a neodymium magnet—traditional magnets are not strong enough to make the slime move!!
DR. KATE BIBERDORF, also known as Kate the Chemist by her fans, is a science professor at UT–Austin by day and a science superhero by night (well, she does that by day, too). Kate travels the country building a STEM army of kids who love science as much as she does. You can often find her breathing fire or making slime—always in her lab coat and goggles.
You can visit Kate on Instagram and Facebook @KatetheChemist, on Twitter @K8theChemist, and online at KatetheChemist.com.
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The Great Escape Page 8
