2013
Oct 29

Ginger-Spooks & Pumpkin Puppets

by Hannah Holt »

7 comments


This week I had a hankering for gingerbread. It might be too early for Christmas music and gingerbread men, but it’s the perfect time for ginger-spooks!

ginger skeletons

Boo! I followed this recipe for ginger cookies, and frosted them monster-style with a simple glaze.

{Note: to pipe designs on the cookies, I filled a sandwich bag with frosting and snipped off one of the corners with scissors. No fancy cake decorating supplies needed!)

ginger skeletons2

They were frightfully good!

We also made paper bag pumpkin puppets. I always keep lunch bags around the house. They are cheap and have so many uses. I cut pumpkin faces and features from construction paper and showed the kids how to glue them to the bags.

 

pumpkin puppetpumpkin puppet1

Happy Halloween!

pumpkin puppet2

 


2013
Sep 26

Carrot Canoes and Archimedes’ Principle

by Hannah Holt »

9 comments


I’m working on a new picture book about buoyancy, so I’ve had boats on the brain lately. Like, could you turn a carrot into a boat?

carrot boat 1

Carrots don’t float. Well, I supposed if you found a dried out carrot it might float, but for the most part carrots sink.

carrot boat 2

{See, I cut off the end of a carrot and put it in water… Thunk! It sunk.}

But what if we took a carrot peeler and hollowed out the inside of a carrot?

carrot boat 3

Ta da! It floats…

carrot boat 4

Now why does the first carrot sink while the second carrot floats? They are both carrots, right?

Let’s talk about buoyancy. Buoyancy is the lift water gives you. You might have noticed you feel lighter jumping in water than on land. That’s because the water pushes you up.

Weee2

How much does water push you up?

water weight

It pushes you up… the weight of the water you just replaced? Or as Archimedes Principle states:

Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

Wow, that was a lot of words! Let’s go back to our carrot. Before we hollowed out our carrot, water still pushed up on the carrot. But the carrot was heavier than the amount of water it moved. In other words, it was too dense. So it sank.

carrot before and after2

In the second case, the carrot was lighter. The water could hold it up and it floated. You can make a carrot into a boat!

A few activities by grade-level:

Kindergarten-1st Grade: Take a potato, an apple, a carrot, and a pea. What ones float? What ones sink? Make a hypothesis: What else do you think will float? Now test it.

2nd -3rd Grade: I started with 2 cups of water (about 500 mL). The carrot and the water together have a volume of 2 ¼cups (about 525 mL). How big (in volume) is the carrot? Answer: ¼ cups big (or about 25 mL in volume)

4th – 5th Grade: One milliliter of water (volume) has a mass of one gram. The carrot took up 25 milliliters of water. How many grams of water did the carrot replace? Answer: 25 grams {You might have to walk them through this.}

6th Grade: Archimedes’ Principle says that the buoyant force on our carrot can be found like this:

The Volume of the Water (displaced by the carrot) x The Density of the Water x Gravity

If the Volume of the Water = 25 (cm³)

and the Density of the Water = 1 (g/cm³)

and Gravity = 10 (m/s²… I rounded for calculating ease.)

What is the buoyant force on the carrot?

{Answer: 25 x 1 x 10 = 250 g• m/s²} Advanced students might be interested in the units, but the main goal here is to try and plug the values into the equation.


2013
Jun 08

Cupcake Trains (and Atom Packing)

by Hannah Holt »

7 comments


***First off, I have two giveaways on my Facebook Page this week. I’ll be doing the drawings later today, so be sure to enter soon.***

Now, here’s how to make a train out of cupcakes:

Train cupcakes

I mixed a little extra powdered sugar into my butter cream frosting to stiffen it up. But even so, some of the frosting dripped between the cupcakes. I could have packed the cupcakes more tightly, but then I wouldn’t have had the train shape I wanted, which got me thinking…

What can cupcakes teach us about organic chemistry?

Well, quite a lot, but I was thinking about atom packing. In the above, I packed my cakes together more or less like this:

loose packing

You can see the gaps between the cupcakes are fairly large, but I get nice straight lines and a rectangular shape. I could have packed them much closer together like this:

tight packing

Here you see the gaps are smaller. I probably wouldn’t get any frosting drips between these cakes, but it has the wrong shape. This might be perfect for something like a flower or clown face.

So what does this have to do with chemistry? Well, let’s consider two items with the same chemical make up: diamond and graphite.

diamond and graphite

How can two items, both made completely of carbon, have such different properties? The secret is in the packing.

Graphite has a lot more gaps (or frosting drips) in it’s structure. Its layers are bonded together loosely, so it will flake and rub off.

Diamond, on the other hand, is made entirely of strong bonds. So while graphite is good for sketching, diamond would be better suited for etching. Different “packings” will result in materials with different uses, just like my cupcake arrangements.

This isn’t a perfect analogy because I’m comparing a two-dimensional model (cupcake packing) to a three-dimensional one (crystalline structure). But the principle is the same, and I thought this might be a fun example for young children. Older kids could do something cooler, like hot-gluing ping-pong balls together:

{Image from the Purdue University Chemistry department website.}

Science is everywhere. :)

 

 


2013
May 27

Army Man Snack

by Hannah Holt »

7 comments


I was grocery shopping the other day…

grocery shopping

…and it dawned on me, Do you know what Colby-Jack cheese looks like? It looks like army fatigues.

I don’t normally buy sliced cheese (because how hard is it to slice cheese, really?), but I was in a lazy mood. So I bought a package of pre-sliced Cobly-Jack cheese.

And then I was feeling so rested from not slicing all that cheese that I cut it up into an army dude (just add grapes).

Army Man snack

Perhaps, I should have been working on a freelance project, or vacuuming, or making dinner. But sometimes it’s just more fun to cut cheese into people.

For those of you in the States, Happy Memorial Day!

IMG_5074


2013
May 08

DIY Microwave Popcorn

by Hannah Holt »

13 comments


You don’t need a popcorn machine or expensive prepackaged bags to make popcorn at home. All you need are popcorn kernels (I buy them in bulk for super cheap) and a paper lunch bag.

diy microwave popcorn

It’s soooo easy. Just take a handful of kernels (about 1/4 a cup) and pour them into the bag. Fold the top of the bag three or four times and cook them in the microwave until the pops are one second apart. The “popping time” will vary depending on your microwave’s power. For my microwave 1 min and 30 seconds is the perfect time. DO NOT USE THE POPCORN BUTTON.

Other options:

Lightly Buttered Popcorn: Before placing the bag in the microwave, drop a pat of butter into the bag with the kernels. Most of the butter will end up on the bag, but the popcorn will have a buttery aura. Yum!

butter butter bag

Caramel Corn: Melt 2 Tbs of butter and mix in 1/4 cup of brown sugar. Chill the mixture in the fridge until it’s solid (about 30 minutes). Place this with the kernels in the bag and pop for slightly less than the above method. For my microwave this is about 1 minute and 15 seconds. Some kernels will be left unpopped, but if you do it for the full length of time the caramel will burn. If it burns, it will taste very, very bad. When in doubt, under cook it.

Why DIY popcorn?

Making your own microwave popcorn is cheap and easy. Also most prepackaged microwave popcorns contain TBHQ (or a similar preservative). In small doses TBHQ has no observable side effects, but in larger doses it is linked to stomach tumors and all sorts of other nasty stuff.

Will eating a bag of store bought popcorn give you stomach cancer? Probably not. But these added ingredients have no nutritional value and making your own microwave popcorn isn’t any more difficult than throwing a store bought bag in the microwave. So why not skip the mystery ingredients all together?

Happy snacking!