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Halloween Science!

 

Halloween is a great time to experiment and dazzle with science!

 

handsArticulated Severed Hand

Want to know how your hand works? You don’t actually have any muscles in your fingers. So how can they move? Make your own moving hand with paper and straws.

 

What You Need

Card stock paper or foam

Pencil

Scissors

Tape

Straws

String

Beads

 

What You Do

  1. Trace your hand on the paper and cut it out.
  2. Feel the bones in your fingers. How many do you feel? (three.
  3. Make lines on your paper hand where the lines on your actual fingers are.
  4. Cut three straw segments for each finger.
  5. Tape the segments on the hand. Make sure you have about ¼ inch of sopace between each straw.
  6. Feel the bones in your hand. How many can you feel? (five?)
  7. Cut five straws and tape them to the hand.
  8. Cut 5 pieces of string 1 foot long each.
  9. Tie the end of each to a bead.
  10. Thread the string through the straws of each finger and hand bone.
  11. Pull on the strings to see your hand move.

What’s Going On?

Hands are amazing! They are brimming with nerves which allow you to feel, blood vessels for bringing in nutrients and taking waste away, and bones.

There are 3 bones in each of your fingers, and 2 in your thumb. These bones are called phalanges. The phalanges connect to 5 bones in the main part of your hand, called metacarpals. Your wrist is made up of 8 bones that work together and connect to the two lower arm bones—the radius and the ulna. Bones are great, but they don’t move on their own.

Muscles are what move bones, and fingers don’t have a single muscle in them!

The muscles that move your fingers and thumb are actually in your forearm. Place your right hand on your arm right below your elbow on your left arm. Waggle your left fingers. Feel the muscles move?

Attached to the end of the muscles are tough string-like tissues called tendons. The muscles in your arm have long tendons that reach from the forearm muscles through the wrist and palm to the fingers and thumb. Like the strings in the straws, the tendons slide though little tunnels. The tunnels are called tendon sheaths and they are stuck to the bones in your fingers and thumb. This keeps all the tendons in place. When the muscles in the forearm contract, they pull on these tendons to move the bones.

hand7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mummified hotdogs

King Tut’s got nothing on you! There’s a science of mummification and it’s all about sucking out the moisture and killing off the little bugs that break tissues down.Make your own mummies by preserving hotdogs with kitchen chemicals.weiners

 

 

What You Need

3 Hot dogs

3 Airtight plastic storage box with lid that is longer, wider, and several centimeters deeper than the hot dog. Or you can use Ziploc baggies

A box of Baking soda

Salt—one whole container

marker

 What You Do

  1. Put one hot dog in each baggie.
  2. Zip one shut and label that baggie “Control”. You won’t mummify this one. You’ll just see what happens to a hot dog when you do nothing and leave it out.
  3. In the next bag pour enough baking soda over the hot dog that it disappears entirely. You want to make sure every part is covered. Zip it shut. Label it “baking soda” .
  4. In the last bag cover the hot dog entirely with salt. Zip it shut and label it salt.
  5. Label all the baggies with the date and set them aside.
  6. Check back on your mummies after two days. What do you notice?
  7. Check back after four days. A week.
  8. How do the mummified hot dogs compare to the untreated one.

Want to take it further?

You’ll need these tools to measure the length, diameter and weight of your hot dog mummy at different stages of the experiment.

Ruler

Piece of string or yarn (at least 10 cm long)

Kitchen scale,

Lab notebook and pencilWhat changes do you see? Which material makes the biggest change? How do your mummies feel? Record your findings in your notebook.mummy

 

 

 

 

 

 

 

Dry Ice Crystal Ball

You can make a great crystal ball bubble with smoke swirling around inside. All you need is a little chemistry!

fortune-teller-crystal-ball

What You Need

Dry ice

Warm water

A bowl with a smooth lip

Bubble solution

A rag

 

What You Do

  1. Fill your bowl ¾ of the way with warm water.
  2. Place a chunk of dry ice in the bowl. (Get a grown up to help and use gloves. This stuff is SUPER cold and can burn fingers. Use a piece of ice about the size of a golfball.)
  3. Dip your rag into the bubble solution and stretch it across the rim of the bowl. Swish the rag across the whole opening of the bowl to create a film.What’s Going on?
  4. As the dry ice sublimates, the carbon dioxide vapor is caught inside the bubble solution. The bubble expands, but the cooled bubble solution does not evaporate quickly so the bubble lasts for a relatively long time.
  5. Dry ice is solid carbon dioxide. It’s COLD! When you add it to water it immediately goes into a gas form. It looks like it is boiling. This is called sublimation.

 

 

 

 

 

Rainbow Inspired Science

rainbowWith all this wacky spring weather you never know if it will be sunny or raining or both when you look out the window. Lucky for us that means plenty of rainbows. And THAT means plenty of inspiration for science projects.

Why do rainbows happen anyway? Sunlight is made up of white light. But white light is made up of other colors. When it shines through the air we see white light, but when it hits something like water, or glass, it slows down and kind of takes a right turn. Colors that have longer wavelengths don’t turn as much and colors that have shorter wavelengths turn more–so the colors get fanned out into a rainbow.  The water or glass that slows the light down and fans it out is called a prism.

It’s ALWAYS the same order Red, Orange, Yellow, Green, Blue, Indigo,  Violet (ROY G. BIV)

One experiment I love is to make a Spectroscope so kids can actually see the different colors that make up sunlight AND see the pattern.

 

Make a Spectroscope

All you need is an old CD and a paper towel tube to make this cool machine.

 

What you need

 

  • Empty paper towel roll
  • Craft knife and/or scissors
  • Blank or old CD
  • Pencil
  • Small piece of cardboard or cardstock
  • Tape

What You Do

  1. Stand your tube on the counter. Near the bottom, use a craft knife (an adult should do this) to cut a frown-shape slit.spectroscope

 

 

 

 

2. Directly across from the slit, make a small peephole or viewing hole using your craft knife (another step for an adult).sepctroscope slit

 

3. Trace one end of your paper towel roll onto your small scrap of cardboard or cardstock. Cut it out.

4. Cut a straight slit right across the center of your cardboard circle.

5. Tape the circle to the top of your spectroscope.

6.Insert the CD into your 45° angled slit with the shiny side facing up.

 

 

7. Take your spectroscope outside. Point the top slit up at the sky (NOT directly at the sun). Look through the peephole. What do you see?Now try your spectroscope with other light sources like fluorescent light, neon light and candle light. Compare what you see.

 

What’s going on?

A CD’s surface is mirrored with spiral tracks scratched into it. The mirror part reflects light to your eye and the tiny ridges diffract light and separate the colors of white light.

Cookie Chemistry

chocolate-chip-cookie

 

 

 

 

 

 

 

 

 

So, you like to bake –say chocolate chip cookies–but you’re not a fan of science?

I’ve got news for you! Bakers are mad scientists. Think about it. You first gather your materials and make a mixture—dough. You put some energy to it—thermal energy—heat—and that sets off a bunch of chemical reactions. You transform one thing—dough—into another–cookies

 

 

Let’s take a look at the chocolate chip cookie timeline of chemical reactions.

cooking science

When you bake a cookie, here’s what’s going on, step-by-step.

  • 92 °–the spread: As the cookie dough starts to heat up, the butter inside it melts. The cookie dough begins to turn more liquid and gradually spreads out. As the cookie spreads, the edges thin out. This, coupled with the fact that they are fully exposed to the heat of the oven and are constantly reaching hotter areas of the baking pan, causes them to begin to set long before the center of the cookie does.
  • 136°–Goodbye salmonella–Salmonella bacteria can survive for weeks in eggs. This can make you really sick. This is why you shouldn’t eat cookie dough. 136° is too hot for them and they die.
  • 144° Egg proteins begin to change. In a raw egg, proteins look like coiled up balls of string. As they get heated they unwind and then get tangled up all together This is how eggs go from runny to solid when they get heated. Which is cool because most things turn from solid to liquid when they get heated, right?
  • 212°–The rise: The water in the dough turns into steam at 212°F. The cookie starts to rise as the vapors push through the dough. Eventually, the baking soda or powder starts to react with the acids in the brown sugar and break down into carbon dioxide gas, which raise up the cookie farther. All these gases leave little holes in the maturing cookie, which makes it light and flaky.
  • 310° –The tasty reaction—The Maillard reaction happens when sugars and proteins break down and rearrange themselves. The molecules are ringlike in shape and they reflect a certain light—brownish light—this is what makes toast and other things toasty brown. It produces all sorts of toasty, nutty and even savory flavors.  
  • 356°–caramelization–As sugars in the dough break down, they transform from clear, odorless crystals into a brown, fragrant liquid that’s overflowing with aromas and tastes — think butterscotch, sweet rum and popcorn.
  • The cookie cools. Once it comes out of the oven, the process isn’t over yet. Remember that liquefied sugar? Well as the cookie cools, that liquid sugar hardens up, which can give the cookie an extra-crisp, toffee-like texture around the edges. Meanwhile, the air inside cools, which causes the cookie to deflate slightly.

chemical change

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

How Cookies Crumble

Most chocolate chip cookie recipes have the same basic ingredients and technique: butter and sugar (a mix of white and brown) are creamed together with a touch of vanilla until fluffy, eggs are beaten in one at a time, followed by flour, salt, and some sort of chemical leavening (baking soda, baking powder, or a bit of both). The mixture is combined just until it comes together, then spooned onto a baking sheet and baked.

What kind of cookie do YOU want?

Engineering the perfect cookie for you!

You like chewy?

You like cakey? You like crispy?

No problem.

 

It’s all about the variables.

 cookie science 2

 

 

 

 

 

 

Chewy

  • 2 1/4 cups bread flour
  • 1/2 teaspoon baking soda
  • 1 cup (2 sticks) unsalted butter, room temperature
  • 1/2 cup granulated sugar
  • 1 cup packed light-brown sugar
  • 1 teaspoon saltchewy
  • 2 teaspoons pure vanilla extract
  • 2 large eggs
  • 2 cups (about 12 ounces) semisweet and/or milk chocolate chips

 

  1. Preheat oven to 350 degrees. In a small bowl, whisk together the flour and baking soda; set aside. In the bowl of an electric mixer fitted with the paddle attachment, combine the butter with both sugars; beat on medium speed until light and fluffy. Reduce speed to low; add the salt, vanilla, and eggs. Beat until well mixed, about 1 minute. Add flour mixture; mix until just combined. Stir in the chocolate chips.
  2. Drop heaping tablespoon-size balls of dough about 2 inches apart on baking sheets lined with parchment paper.
  3. Bake until cookies are golden around the edges, but still soft in the center, 8 to 10 minutes. Remove from oven, and let cool on baking sheet 1 to 2 minutes. Transfer to a wire rack, and let cool completely. Store cookies in an airtight container at room temperature up to 1 week.

 

Cakey

cakey

  • 2 1/4 cups cake flour
  • 1/2 teaspoon baking soda
  • 1 -3/4 sticks unsalted butter, room temperature
  • 3/4 cup granulated sugar
  • 1/4 cup packed light-brown sugar
  • 1 teaspoon salt
  • 2 teaspoons pure vanilla extract
  • 2 large eggs
  • 2 cups (about 12 ounces) semisweet and/or milk chocolate chips
  1. Preheat oven to 350 degrees. In a small bowl, whisk together the flour and baking soda; set aside. In the bowl of an electric mixer fitted with the paddle attachment, combine the butter with both sugars; beat on medium speed until light and fluffy. Reduce speed to low; add the salt, vanilla, and eggs. Beat until well mixed, about 1 minute. Add flour mixture; mix until just combined. Stir in the chocolate chips.
  2. Drop heaping tablespoon-size balls of dough about 2 inches apart on baking sheets lined with parchment paper.
  3. Bake until cookies are golden around the edges, but still soft in the center, 8 to 10 minutes. Remove from oven, and let cool on baking sheet 1 to 2 minutes. Transfer to a wire rack, and let cool completely. Store cookies in an airtight container at room temperature up to 1 week.

 

 

Crispy

  • 2 1/4 cups all-purpose flour
  • 1/2 teaspoon baking sodachocolate-chip-cookie
  • 1 1/4 cups (2 1/2 sticks) unsalted butter, room temperature
  • 1 1/4 cups granulated sugar
  • 3/4 cup packed light-brown sugar
  • 1 teaspoon salt
  • 2 teaspoons pure vanilla extract
  • 2 large eggs
  • 2 cups (about 12 ounces) semisweet and/or milk chocolate chips
  1. Preheat oven to 350 degrees. In a small bowl, whisk together the flour and baking soda; set aside. In the bowl of an electric mixer fitted with the paddle attachment, combine the butter with both sugars; beat on medium speed until light and fluffy. Reduce speed to low; add the salt, vanilla, and eggs. Beat until well mixed, about 1 minute. Add flour mixture; mix until just combined. Stir in the chocolate chips.
  2. Drop heaping tablespoon-size balls of dough about 2 inches apart on baking sheets lined with parchment paper.
  3. Bake until cookies are golden around the edges, but still soft in the center, 8 to 10 minutes. Remove from oven, and let cool on baking sheet 1 to 2 minutes. Transfer to a wire rack, and let cool completely. Store cookies in an airtight container at room temperature up to 1 week.

 

Try changing it up. How do your cookies change when you melt butter? How do they change if you add less flour? What happens if you add a bit of corn syrup in with the sugar?

What if you use gluten free flour?

 

As a good scientist—you have to repeat your experiments many times!

Teabag Ghosts

witchy tea

 

 

 

 

 

 

 

 

 

 

 

 

 

 

These teabag ghosts really fly high when conditions are perfect.

What you need:

  • Teabag with a string and label
  • Non-flammable plate
  • Scissors
  • Lighter or match

What to do:

Remember – always ask an adult for help with matches and don’t do this experiment near any flammable materials.

  1. Remove the staple, label and string from the teabag.
  2. Pour the tea out.
  3. Unfold the teabag.
  4. Turn the teabag into a cylinder.
  5. Draw a ghost face.
  6. Stand the ghost on one end on a plate. Make sure it’s on a flat surface.
  7. Use a lighter or match to set the top of the teabag cylinder on fire.

teabag ghost burning

What happens? You should see the ashes of the teabag fly into the air!

What’s Going On?

When you light the top of the teabag, the air inside the cylinder heats up. When air molecules heat up, they move around more and more and take up more space. As they spread out, the air inside the cylinder becomes less dense. The air around it is more dense. Warm, less dense air gets squeezed up above cool, dense air.  As the warm, less dense air rises, it has enough force to lift the ash of the teabag straight up into the sky.

teabag ghost

Sizzling Summer S’mores in a Pizza Box Solar Oven

BBQ hot day

Harness the power of the sun to cook. It doesn’t take much to make your own portable camp oven. All you need is a pizza box, some tin foil, plastic wrap and a sunny day to get cooking

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

What You Need:

  • 1 large size pizza box
  • Several feet of aluminum foil
  • 1 sheet black construction paper
  • 2 1/2 feet of clear plastic wrap
  • 4 feet of masking tape
  • 2 feet of string
  • Scissors
  • White glue
  • Ruler
  • Marker

What You Do:

  1. Open up the pizza box.
  2. Glue aluminum foil –shiny side up– to all inside surfaces of the box–except the top. Close the box.
  3. On the outside area of the top flap of the pizza box measure 1 inch from the edge on all sides and draw a square.
  4. Have a grownup help you cut along three lines of the square, leaving the fourth line along the box’s hinge uncut.
  5. Then fold open the flap, making a crease along the fourth line
  6. Open the box and glue aluminum foil to the inside surface of the top flap.
  7. Be careful to make as few wrinkles as possible in the foil, and smooth out whatever wrinkles occur.
  8. Tape the black construction paper to the inside bottom of the box. (This will help to absorb the incoming sunlight.)
  9. Carefully stretch the plastic wrap over the opening of the box, sealing the edges with tape to seal the air in.
  10. Cover any air leaks around the box edges with tape. Make sure the box can still be opened, so you can place food inside the box and remove it later.

 

To cook stuff:

  1. Go outside in the sunlight and place oven on a flat, level surface. This really works only on sunny days at peak sunlight hours—from 9-3 are best.
  2. Place your s’mores in the oven.
  3. Use string and masking tape to tie back and adjust the flap so that sunlight is reflected into the oven.
  4. Let your s’more cook, and check the angle of the flap once in a while to make sure the sunlight is getting inside the oven. Watch your food is get melty and
  5. When it looks good, take it out and enjoy your solar s’more!

s'more