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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

 

Fern Smash T-Shirt

fern Here’s a fun project to do with the kids to make a memorable t-shirt. Collect leaves while hiking and then use them to make art.

 

What You Need

  • hammer
  • thin piece of cardboard (not corrugated)
  • Fresh fern or leaf (NOT poison Ivy!)
  • T-shirt
  • paper towel

 

What You Do

  • Put a piece of cardboard inside your T-shirt so the stain won’t soak through to the back.
  • Place the leaves on your shirt in whatever design you like.
  • Place a couple of paper towels over the ferns
  • Carefully hammer over the whole fern. You have to hammer the complete design or it won’t show up on your T-shirt.
  • When you’re finished, remove the paper towels and lift off the ferns.
  • Keep it out of direct sun. The sun will fade the design.
  • When you get home, toss the shirt in the dryer for 10 minutes to set the design.

fern_3

What’s Going On?

You’re making a grass stain! When you hit the leaf with the hammer, the cells break open and the green pigment, chlorophyll, leaks onto your shirt. Plants need this green chemical to make sugar with sunlight. It’s amazing. Plants are the only things that can create their own food from the sun.

Lucky for us, it stains! We can use the color to make prints on cloth or paper.

 

Try it!

 

 

Want more fun things to do outside? Check out my book Camp Out! Then go out and have fun!

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