Homeschool Biology: Shrink Plastic Cell Models, and 14 Other Cell Models

February was so busy with Girl Scout cookie business that I could hardly find time to work on new lesson plans, grr. In some ways that worked out well--Will got a lot more time to work on AP European History and algebra, and Syd got a lot more time to sneak off and make art--but I got frustrated at continually delaying many of our in-depth lessons in science and robotics. 

For science, at least, I finally decided that since we weren't moving forward, we'd instead review by completing some of the lessons that I'd planned for the kids in earlier chapters but that we'd skipped or skimped on for whatever reason. 

And that's how we found ourselves one afternoon hanging out on my bed with kettle corn and tea, me working on Girl Scout cookie accounting and the kids watching Crash Course videos on cell biology and coloring shrink plastic cell models.

I think handmade models have a hugely important place in the learning process. Just as I liked, when the kids were little, to give them lots of moveable alphabets in as many different style and materials as possible, I like having my older kids make models of what they're learning whenever possible, and, if possible, in a multiplicity of styles and materials. Just the repetition of building and identifying the key components in each model aids learning, of course, but creating a variety of models improves and refines the way that the brain categorizes the information, as well. 

And of course if it's fun, that's when the best learning takes place!

Kids can draw their own cell models on shrink plastic sheets, or trace any good coloring page drawing, but we use these shrink plastic cell model templates. The kids trace the outline in Sharpie on the shrink plastic sheet, and then color in and label all of the organelles.

And then we shrink them in the oven. It's excellent fun.

Make the shrink plastic cell models for sure, but here are plenty of other cell model projects to keep you occupied every time you spiral back to cell biology--or just anytime you're feeling crafty!

1. edible cell model. The girls have made these in both cake and cookie versions. Both are super easy if you have a square and a round cake pan; kids can choose the frosting and candy (or fruit) decorations to model the organelles. Rice Krispy Treat cell models and sushi cell models are no-bake options.
2. 3D pen cell model. The kids received a 3D pen for Christmas, and we're still learning all the awesome things to make with it. This is one more!
3. Altoid tin cell model. This is a good upcycling project if you can get your hands on the Altoids tins. You could put each type of cell model in each compartment, or use one compartment for the model and the other to hold definition cards of the organelles.
4. animal cell cookie cutter. I do not own this cookie cutter--I just want to!
5. cell coloring book. The coloring book is legit and I have it, although I gave them a burner email address (of course!) to get it.
6. cell model T-shirt. I LOVE this idea! If kids put a lot of craftsmanship and care into it, they'll be able to wear it until they grow out of it, showing it off and reinforcing the identifications possibly hundreds of times.
7. felt cell model. This model would be super cute for an older kid to create, or for an adult to create for a very young learner. I totally should have made my babies cell model stuffies!
8. giant inflatable plant cell. Um, this plant cell model is AMAZING. Not only does the tutorial include instructions on sizing each 3D organelle model correctly, but it teaches you how to make an inflatable walk-in plant cell model from plastic drop cloths, duct tape, and a fan.
9. LEGO cell model. I like the simplicity of this cell model, as well as how easily LEGOs lend themselves to making a plant cell, in particular.
10. organelle models. As the kids grow older, we're more drawn to the types of models that aren't just step-by-step tutorials, but require problem-solving and engineering to construct.This is one such project, and although the post focuses on organelle models, I think it would be really cool to turn this into a large-scale project by modelling ALL the organelles and turning your entire family room into one giant cell. I mean, you're a homeschooler--your family room is SUPPOSED to look like some weird, over-elaborate educational project.
11. plant cell model on a Styrofoam meat tray. I wouldn't use a Styrofoam meat tray because I think it's gross, but it IS just the right shape for a plant cell...
12. play dough cell model. If you don't need more stuff to display forever, then a play dough cell model might be the way to go.
13. polymer clay cell model. OMG, this would be right up Syd's alley!
14. toolbox cell model. I like that this cell model includes lots of random bits and pieces from around the house and garage, including a couple of different kinds of screws and a brillo pad.

February Favorites: From The Bone Wars To LOTS of Matches

Here's what we've been loving this month!

BOOKS

Hold my breath and knock on wood, but I have gotten both kids to join me in keeping their reading logs up to date!

Syd happily listens to anything that Chris Colfer narrates over and over again, and read LOADS of the Wings of Fire series this month, but somehow, I have no idea how, she also found her way to...

Michael Crichton?

I don't know. The first that I knew of it, she was raving to Matt about a book she was listening to about these two guys who were fighting over fossils and it was getting super crazy. My ears perked up at this and I interrupted with, "Wait. Are you reading about the Bone Wars?!?"

"Uh, yeah."

I couldn't wait to know who had written a history book that had so immersed my kid. "Who wrote it?" I asked her eagerly.

She checked her ipod. "Ummm.... Michael Crichton."

Friends, 'tis true!



I've got a paper copy on hold from the library for me.

Syd also read and adored this likely much more kid-appropriate book this month:



I think she learned the word "bittersweet" from this book, and from me as I was describing to her how I felt while reading one of the book's final scenes.

Here's what else Syd read this month:



Will, to my delight, got completely immersed this book last month:



I re-read it as soon as she was done with it, and we've since spent tons of happy hours gossiping about the Bennets and Mr. Darcy and how ridiculous they all are. They spend all their time gossiping and scheming, and it. Is. AWESOME. And every time Elizabeth and Darcy bicker, Will was all, "OMG, could they possibly flirt any harder?!?"

Naw, Girl. They could not.

Here's an interesting article about the Regency Period, because I know you were dying to understand the politics underpinning Austen's novel.

Will re-read this book this month--



--and it's one of my favorites, too! It's surprising and funny and the plot is quite sophisticated. If you ever read it, please Comment and let me know: Real, or all in the protagonist's head?

This one was another of Will's favorites:



I haven't read it yet, but she put it on my library shelf for me to read, so I will.

Here's what else Will read this month:

I didn't get as much reading done last month as I usually do, but there were still a few stand-outs.

I chose this book entirely because I realized that I don't know anything about Ada Lovelace. Before I was halfway through, I found myself OBSESSED with her, and with Lord Byron in a low-key way--if anyone can recommend a stellar biography for him, please do!

Ada Lovelace was freaking AMAZING, you guys! When her buddy, Charles Babbage, basically invented the computer in the Victorian age (not that he knew that was what he invented, which is the entire point of why Ada was so amazing), Ada, this super mathematical genius who never got to do cool math stuff, volunteered to translate an article about it. But then, in one of the appendices to the article, she was all, "Hey, y'all, if you ever wanted to tell this machine that doesn't even exist yet how to do this specific thing, this is how you'd do it," and then went on to write an entire computer program. The world's first computer program. For a completely theoretical computer that hadn't even been actually built yet.

After I finished the book, I also watched this great documentary on her--

--and here's the difference engine in all its glory:



One of my favorite things is how adorable it is with all its cogs and wheels. And every time somebody invented something, somebody would say, "Hey, you know what we should do? We should power it with a STEAM ENGINE!"

It's absolutely enchanting. I'm utterly charmed.

My other major favorite this month is this super spooky yet YA-appropriate graphic novel:



Will read this one, too, and we're anxiously waiting for the next volume.

VIDEOS

Syd is the best at finding us super weird YouTube videos. She's currently obsessed with this one:

I don't even know.

We watched Venom for family movie night this week, and Syd was so interested in the abstract art that they show during the end credits that she tried searching for it, and instead sent us all down a looooong rabbit trail of watching artists create sophisticated, elaborate fan art pieces over time lapse:



At a Girl Scout cookie booth a couple of weeks ago, this guy came by with a weird Segway-looking skateboard, and Will and her friend were so fascinated with it that they peppered him with questions as he was packing away his groceries, putting on his helmet, and getting it set up. He was perfectly amiable and kindly answered all of their questions until he finally stepped onto this thing and absolutely flew out the door and down the sidewalk past the grocery store's picture window. He was going SO FAST!!!! We decided that he is easily the coolest guy in town and we are definitely his friends.

Will was so impressed that as soon as we got home she looked it up. It's a Onewheel, and it really IS that cool!



I don't know why we watched this. There's a lot of that kind of nonsense in our Recommended feed:



Goals for this month:

I'm going to sneak in some more learning about the Bone Wars, now that it's snagged Syd's interest.

Will needs a little more non-fiction in her diet. Any suggestions?

Now that cookie season is winding down, maybe *I* can get some more good books read, starting with the ones that Will has already recommended to me.

And... umm... I bought a giant multi-pack of matches... I don't want to say anything more about that.

P.S. Want to know more of our recommend stuff as we decide we love it? Follow along on my Craft Knife Facebook page!

Girl Scout Cookie Booth Math: Equal It Out and Assign It Fairly

We've gone through several iterations of the cookie booth tracking form. This is the most recent!

Okay, you guys. This is why you studied algebra. You studied algebra when you were 13 because one day you'd be a Girl Scout troop leader, and your Girl Scouts would go mad for cookie sales, and you'd have to schedule nine kids into 40+ hours of booths every week, and then you'd have to figure out how to divide the booth sales fairly between everyone who worked, for all the various hours they worked, and you'd also have to make sure that your booth sales matched your booth inventory every time, and that your physical inventory matched what your database says you have.

And don't forget that you'd have to figure out how many of each type of cookie to even bring to every booth in the first place!

Functional literacy in math. That's what algebra gives you.

The most important thing is that whatever method you use, you MUST WRITE EVERYTHING DOWN. An accurate paper trail is key. Count your inventory. If it's off, note it. Count your money. If it's off, note it. Know exactly how many boxes of each variety of cookie you're taking to each booth. Know exactly how much starting cash you're taking. Know exactly what kids and what adults worked there, and exactly how long they worked. Know what you took in via credit cards. Know what you took in via cash.

The key to doing all that easily and efficiently is using a booth form. Some councils make their own, and you can find them if you Google, but if you know exactly what information you want on your form, and especially if your partner is a graphic designer (yay!), then you can make your own. 

At the top of my form I fill in the booth location, time, and date. My Girl Scout troop works so many booths that we might be back and forth between the same location twice in one day, or three times in a weekend.

Below that is space to write in all the kids and adults who worked, and the hours that they worked. We sometimes have booths that are six to eight hours long in a single spot, and have to be able to record kids coming and going all day for various hours, or even taking a break and coming back later. You also need to know all the adults who were present, if for no other reason than you know who to loop into the mass text if the numbers come out wrong.

Next come a series of boxes that are specific to what our troop needs. The first box is to record the amount of money in the Operation: Cookie Drop/Cookies for a Cause donation can. The second box holds tally marks that must be made every time someone runs a cookie donation on credit card, because our credit card processing company doesn't let you look at transaction details easily--if someone thinks that they might have forgotten a cookie donation credit card transaction, or if the final amount is off, I have to manually click through every single transaction to see its details, and it. Is. TEDIOUS.

The third box records the amount in our own troop donation can, although this is not incorporated into any other calculations. Early in the season, the kids were trying to collect enough donations to buy a box of Girl Scout cookies for every kid in our local Backpack Buddies program, and so we'd often use the box to record that, instead. If we do local donations again next year, I will likely include yet another box just for that.

The next couple of boxes are so that adults whose phones were used to run the credit card processing app can record their transaction totals. Adults come and go, too, so you need more than one box for this.

The final two boxes record the amount of starting cash and ending cash. Our cookies are all $5, so we start with $200.

2023 Update: Our cookies are now all $6 a box, so we go back and forth between starting with $200 or $300 while we try to decide which is better. Whatever number we use, we record it!

I devote a lot of space simply to the cookie inventory. Using a lot of space to keep the numbers separate helps avoid confusion, and the color coding and illustrations are visual reminders to help keep everything correctly sorted by type. The bigger spacing lets the kids, who often can't write tiny, also do inventory, and it leaves some room for calculations.

Notice that unlike a lot of booth tally sheets, mine doesn't include a place to record parents who take cookies from the booth supply to add to their kid's personal orders. I HIGHLY discourage doing this at cookie booths, because it's not the time and place and it's distracting, but in case of emergency I'll do it and just subtract what they take from the starting inventory of that booth. Another reason for all that space between the inventory number boxes!

Below the inventory section is where you walk through the two main booth calculations: the calculation of inventory, and the calculation of money. The first line is inventory, so you copy down what you sold of each type of cookie, then what you sold of Operation: Cookie Drop/Cookies for a Cause (include what you sold from both the donation can and by credit card). Add those together, multiply by the cost per box of cookies, and you'll see how much profit you earned.

The second calculation is just of the money. Copy down your ending cash, then your starting cash, and subtract them. Add to that your total credit card sales and the amount in the Operation: Cookie Drop/Cookies for a Cause can (do NOT include the amount on credit card here, because that's already included in your credit card sales). Does your final answer equal your final answer from your cookie inventory?

If yes, YAY!!!!!

If no...

1. Recount your cookies. And I mean REALLY recount them! Are you trying to count them in your car? Unload them all and spread out so you can see what you've actually got. Repack everything so that you have only one partially full case of each type and the rest are all full cases--multiple partial cases of the same type of cookie are inefficient to carry and a nightmare to count.
2. Recount your cash. Get someone else to count it this time, or ideally two someones.
3. Double-check your credit card transactions. Log out and then back into your processing app to make sure its transaction record is completely current. Make sure no other adults ran credit cards on their phone and just forgot to record it. If you use Digital Cookie, double-check that no adults accidentally ran cards through their kid's site instead of the troop's site. Look through each transaction and make sure you didn't charge someone twice. If a credit card transaction seems weirdly large, see if anyone remembers a customer buying a ton of cookies at once--if nobody remembers it, someone probably punched something in wrong during the transaction.
4. Recalculate all of your math. Do the inventory subtractions again, with a calculator if necessary. If you're counting by cases, again, use a calculator to make sure you've got the total number of boxes correct. 
5. If you can, compare your current total troop inventory to the total troop inventory that you should have. I can rarely do this, because I've got multiple booths going at one time, but if you've just done one booth, then a whole troop inventory might find that you mysteriously are missing a box or have an extra box that will match what you're over or under.

Here's what these booth forms look like in real life:

You can see we write all over them and alter them however we need to. Next year's updated form might include a Notes area, because there are often extra details we want to record...

...such as how on earth we can end up with $817, when all of our cookie boxes are FIVE DOLLARS EACH. I SUPER love it when everything equals out, and I have to admit that when we're over or under, even by a little bit, it drives me nuts.

ESPECIALLY when we're over by a number that doesn't even equal a box of cookies!

Thankfully, we mostly equal out:

But sometimes we don't, sigh:

But mostly we do:

So how do you assign all of these sold cookie boxes fairly to kids who worked varying hours at each booth?

You turn it into a rate-time-distance problem!

Distance = rate x time. Distance will represent how many cookie boxes a kid sold. Rate is how many boxes the booth sold per hour, and time is how many hours the kid worked.

To find the rate for a booth, add up the total number of hours every kid worked altogether. Let's say Kid A worked 2 hours, Kid B worked 3 hours, and Kid C worked 5 hours at a booth. Maybe they worked all together for part of the time, or maybe they all came in shifts--doesn't matter. Just add up the totals and you have 10.

Divide the total number of cookies sold at that booth by the total number of hours worked. Let's say that this booth sold 100 boxes of cookies. 100/10 = 10, so 10 boxes of cookies per hour worked is the rate for this booth.

Rate x time means that to find each kid's distance, or total boxes of cookies that kid, personally, gets credit for, all you have to do is multiply the number of hours they worked by the rate.

Kid A earned 2x10, or 20 boxes of cookies.
Kid B earned 3x10, or 30 boxes of cookies.
Kid C earned 5x10, or 50 boxes of cookies.

This also works with partial hours. If Kid A had worked 2.75 hours, then they'd have earned 2.75 x 10, or 27.5 boxes of cookies. You can't allocate partial boxes, so someone will have to gain a whole box or lose a whole box somewhere.

If you're mathy, like me, then you can eat up all your free time doing all this pleasant cookie booth math. But even if you're not mathy, you should be functionally literate in math, which means that you should be able to easily handle the calculations required. And, of course, it's very important to give ownership of this process over to the kids, whenever you're able. An elementary school student can do all of the inventory calculations with your oversight. A middle school student can run all of this math with your guidance. A high school student who's had enough Algebra 1 to know how to solve a rate-time-distance problem can do it all without you standing over their shoulder.

And what's more, they SHOULD be doing this. THIS is why we study math. We study it so that we have the tools to solve whatever problems come our way in life. We study it because it's important to be functionally literate in all areas. We study it because we want to be able to calculate, distribute, count, and audit.

We study it because one day we might find ourselves in the Girl Scouts, and Girl Scouts sell cookies!

P.S. Want to read more about Girl Scout cookie booth math and marketing? Here's my complete series (so far!):

• Girl Scout Cookie Booth Analytics, or, Math Helps Girl Scouts Sell More Cookies!
• My Very Own Girl Scout Cookie Booth Calculator: How Many Cookies to Order for Booth Sales
• Girl Scout Cookie Booth Math: Equal It Out and Assign It Fairly
• Girl Scout Cookie Marketing: Kid-Led and Kid-Made Signage and Campaigns

P.P.S. Want to know more about all the weird math I have my kids do, as well as our other wanderings and wonderings? Check out my Facebook page!

Robotics and Programming with Snap Circuits

This semester, we're studying Robotics and Programming. The spine for this unit is the Girl Scout Robotics badges for Cadettes and Seniors, and the Cadette/Senior/Ambassador Think Like a Programmer Journey. Our main manipulatives are LittleBits, Ozobot BIT, and Sphero, although we're bringing lots of other tech into the unit, as well.

Here's what we did for Step #2 of the Cadette Programming Robots badge:

• Simple Sensors with LittleBits

This Snap Circuits activity also meets the requirement for Step #2 of the Cadette Programming Robots badge. For us it's an extension and enrichment, but if you didn't have access to LittleBits but wanted a click-to-assemble option, Snap Circuits are readily available and more affordable. Here are some of our favorite sets:


Since my kids have been playing with Snap Circuits since they were preschoolers, this project was a review of what makes a circuit and a chance for the kids to reinforce the concept by applying it to Snap Circuits. They've been making circuits with Snap Circuits for MUCH longer than they've known what a circuit is, so the activity is a helpful reminder that although some of the vocabulary is new, they're long familiar with the physical setup.

And besides, any excuse to play!

As usual, Will set about making the most elaborate circuit she could manage, and Syd set about making the most annoying circuit she could manage. Somehow she figured out how to turn the fan into a helicopter that would launch itself after a completely unpredictable time pretending to be just a simple fan.

If you don't get hit in the face with something unexpected, then your kids probably aren't having enough fun!

Story Time: Last week, the kids and I volunteered at the Children's Museum in a new-to-us capacity, as volunteers for their regular homeschool classes. We helped with a morning and afternoon session of an engineering workshop, and it was super fun and I hope they invite us to do it again.

As part of the workshop, Will led an activity about determining the correct surface for structures, I led an activity about human inventions that were inspired by nature, and Syd led an activity on communication challenges. Syd's activity was actually identical to one of the suggested activities in the Multi-level Cadette/Senior/Ambassador Think Like a Programmer Journey that we're also working on in this unit, so it was pretty cool that she not only did it, but LED it for two hours!

Anyway, after our part of the workshop was finished, the leader invited us to stay for the all-group activity. She guided all the kids through making light-up LED keychains using pre-cut clear acrylic forms, button batteries, and an LED. We got to scratch decorations into the acrylic, then insert the button battery and LED  into pre-cut holes. After all of our circuitry work, my kiddos immediately knew how to get the LED to light up, of course, but what came next was even cooler.

The leader gave us circle stickers and instructed everyone to use those to tape the LED and battery to the acrylic keychain. She noted that this would make the LED stay lit constantly until it burned out or the battery died, and if we didn't want to do that we could just peel the sticker off and stick it back between the lead and the battery.

Workable, but awfully inefficient, don't you think? I thought that surely I could figure out a better method, and with a little futzing and troubleshooting, I managed to tightly roll a sticker and stick it to the battery so that it pushed the lead away, but not so far that I couldn't simply press the lead back to the battery a little further down. I covered the whole thing with a sticker and there! I'd made my own pressure sensor! Now to light up my keychain, all I have to do is push the sticker button.

All excited and proud of myself, I turned around to show my kids, in case they wanted to do it, too, only to find that they both wanted to show me how they, too, had each turned their LED keychains into pressure sensors that would light up only when they chose. AND each kid had done it in a different way!

If they understand circuits well enough to create their own physical modifications to a circuit to solve a problem, then I think that they understand circuits.

So you know what we're going to do next in Robotics?

We're going to build a functioning hydraulic arm out of Girl Scout cookie cases!

Homeschool Art: The Fake Slime Spill

We did not do this project on the first day of April, but it WOULD make a terrific April Fool's Day prank!

You might remember that Syd has been obsessed with slime since... honestly, I think it's been since before slime became a universal tween obsession. It's been a looooooong time. We've been making oobleck and gak since the kids were babies, but Syd, especially, has taken ownership of the slimer lifestyle since at least 2015.

She did an entire science fair presentation on slime in 2017!

In 2018, while she was away at camp, I set her up with an entire slime studio space, and I haven't yet regretted having one place where all the slime stuff lives.

Well, I mean sometimes I regret it a little, because it usually looks like this:



But whatever. We don't like that carpet anyway. And we didn't keep our stuff nice even before we had kids, so it's not like they're even the main reason that all our stuff looks like junk.

For this art lesson, I found a slime tie-in and we also explored our other favorite pastime, tormenting Matt.

To begin, we watched this excellent video from PBS Digital Studios:



Our local university's art museum actually owns one of these Duchamp fountains, so we've seen it several times before. There are also these stories of artist's pranks to peruse:

• Banksy destroys his painting (and graffiti in general, a topic that we've also explored and that interests Will, in particular)
• Students put a pineapple in a museum.
• Teenagers put glasses on the floor of an art museum.

I think the most salient point to make is that by utilizing an artifact to comment on an aspect of our social conditioning, you can defend the claim that this IS art!

What we're about to do, however, is not art. It's just messing with Matt.

I taught the kids that adding paint to white glue will dye the glue. Here, we're using powdered tempera, ideally to keep the consistency of the glue/paint mixture thick, but you can also use craft acrylics (we still have a couple of bottles of this particular set of homemade school glue dyed with acrylic paint, and they're still great!):

Cover a tray with a piece of waxed paper, then comes the best part: make a spill!

The kids tried a couple of different containers, but the most realistic, I think, was the exact same little deli containers that Syd uses to store her slime. Will made a fake spill from a plastic cup, but it didn't end up looking like anything that would be consumable.

After the spills are settled, you have to find an out-of-the-way spot for them to dry out for several days. I didn't mark the time on this, but I wouldn't have been surprised if it was at least a couple of weeks before the kids could peel their fake spills away from the waxed paper.

Shortly before Matt was expected to come home one evening, Syd chose her favorite of the fake spills and set it on the rug in our family room--not right in the middle, but off in a corner, where it could conceivably have gone unnoticed by us during the day. It was next to the coffee table, as if fallen from where a careless child had set it.

I wasn't in the family room when Matt came through, but I clearly heard him saying, "What is THIS?!? SYDNEY!!!!! GET IN HERE!!!!!!!" Bless her heart, she couldn't even keep a straight face for a second, which just made Matt madder until he reached down to pick up the slime container and the whole thing lifted neatly off the rug and the prank was clear. It was possibly one of the best moments of Syd's life to date.

Unfortunately, the prank only worked once, as a similar slime spill in our bedroom was ignored, and so was one in the playroom (fortunately for Syd, because that one was NOT one of the fake ones...). But the kids had made their point, using a created artifact to comment on the social norms of family life and the surface-level assumptions of what it means to be "clean" in society today.

Okay, I made that up. This one wasn't art--just a prank!

Girl Scout Cookie Booth Analytics, or, Math Helps Girl Scouts Sell More Cookies!

If you've got a troop of motivated kids, then Girl Scout cookie season is BIG BUSINESS. Kids use the money their troop earns during the cookie season for everything they can dream up and plan. Cookie sales have paid for my troop to travel to both Cincinnati and St. Louis, to spend the night at an aquarium and a zoo, to conduct service projects for kids in need in Honduras and in our town, and to supply all the materials and fees for dozens of badge-earning activities and fun bonding activities and adventures both big and small.

In some ways, the math is simple: the more the kids earn, the more they can do with that money. In every other way, however, the math is quite sophisticated: your troop has to order cookies from the council, in most cases before you've sold them, and those cookies can't be returned. Don't sell them all, and instead of the kids earning profits, you'll be in debt to the council. You can sell more cookies at cookie booths in public locations than you can as individuals going door-to-door, but then you need to figure out how many cookies to order from council to take to a booth. Too few, and you've wasted opportunities for more profit. Too many, and you're back to worrying how to sell them all. Take cash to make change and then hope that all the kids (and adults!) count correctly. Take a credit card reader and hope that everyone successfully processes the customers' cards without errors. Count the inventory before and after the booth and do the same with the money, and hope that they both match. Take it all home, count the inventory again, and hope that it matches what your database says you should have. If it doesn't, dig into your non-existent forensic accounting skills to figure out what's wrong and hopefully fix it. Allocate cookies to every kid who worked at the booth, in proportions equal to the hours that they worked. Calculate the percentages of every type of cookie you sold, compare that to your expectations, and then use that to make your next order from council.

Do that over and over and over again. Bonus points if you, as we do, have a troop that runs several booths simultaneously in different places, and even more bonus points on the busy weekends when people are doing inventory and money counting on the fly so that they can pass stuff to another booth starting the next hour across town. And, of course, I'm not even mentioning all the skills that you're also busy mentoring in the kids all this time, and how you're teaching them to do all these things, as well, because that's a given. Add in the extra hours it takes to make sure they understand and take ownership of the process.

Four years ago this was all new to us, and fortunately our goals were set reasonably low, as well (although it didn't feel like that at the time!). Now, of course, we're such old hands that many of the kids beat that first-year goal during pre-orders, and the rest have usually beaten it by the end of the day that cookies finally come in. And yet the kids keep challenging themselves. This year, four of our nine kids (including my own older kid!) have decided to try for 1,000 sales, and one kid who's sold 1,000 for the past two years is this year trying for 1,500. Don't forget that when the kids have big goals you also have to make sure you've got enough booths to make that happen, and please know that angling for booth picks is bloodthirsty business, and you've got to make sure that your orders from council are enough to stock all these booths AND ensure that the kids can meet their goals. You want a little extra, because rarely will a kid be able to meet their goal and then stop selling that second, mid-booth, but again, you don't want too many extra because selling extra troop cookies after you've all met your goals is just about the most miserable work there is.

It's a lot to do, and a lot of it IS luck and guesswork. You can virtually elbow all the other troop leaders out of your way to get the hottest booth pick, only for a winter storm to trash all your sales that day, while all the booths in lousy spots the day before get the awesome pre-winter storm sales. Or maybe last year everybody and their dog was screaming for Do-Si-Dos, so you order them at that percent this year and it takes you a whole season to get through what you'd thought would be one weekend's supply--that happened to me last year with Trefoils, and it was SUPER stressful.

The Great Trefoil Overage of 2018 aside, though, what I've learned is that while much of it is luck and guesswork, a lot more of it is logical and predictable than you might think. If I lay everything out in graphs and charts and numbers, then I can predict quite accurately what percentages of each type of cookie to order, and how many cookies to bring to booths, and which booth spots are the best on which particular dates and times. Just choosing a booth spot that typically sells 10 more boxes of cookies an hour over another equally likely booth spot is a big deal, especially if you can do that consistently over the course of the season.

So here are some of the analytics that I use for my troop's Girl Scout cookie sales. The most important is the one that helps me figure out percentages for ordering cookies from council. The first year the girls sold cookies, I was lost. I tried asking my Service Unit Manager at the time, and she just sort of told me something along the lines of, "Oh, a few cases of Thin Mints and Samoas, a couple of cases of everything else, etc."

I was all, "Seriously? No, seriously. How MANY?!?" It was... unhelpful.

Fortunately, after you have a whole season behind you, especially if you've done several booths, the math is a lot easier. All you have to do is take your booth record sheets from the last year (which you DO have and you DID keep, yes?!?) and calculate the percentages for each type of cookie that you sold at each booth. If you're collecting donations for physical boxes of cookies that you donate locally, don't include those, as you know you mostly take them from what isn't selling as well as it should (and if you're not doing it that way, you SHOULD be!). Also don't include what kids sell individually, because they always sell what they've ordered, even if that means going door-to-door selling nothing but Tagalongs after they've sold out of everything else. Booths should be fully stocked for most of the season, so booth sales should be reflecting what customers actually want, in the percentages that they want them.

Calculate these percentages for several, if not all, of your booths, then average the percentages for each type to calculate the overall percentage of sale for each type of cookie the previous year:

Above is the master document that I make and then pull all of my information from for the rest of my analytics. Notice I've got date, time, day of the week, booth location, number of hours, total sale numbers, percentage of sale for each type of cookie at each booth, and color codes to indicate multiple booths at the same location. It's pretty messy, so you might not be able to see where all that information is, but I assure you, it's there!

That document is all scut work, looking back at the messy handwriting on all of last year's booth tally forms, trying to decipher some fuzzy calculations that were done on the fly, etc., so I don't ask the kids to help with that part. But kids can certainly take my numbers and average the overall percentage for each type of cookie; could even make a pie chart from it, although I find that kind of chart less useful for our purposes. It's good math for a kid, though.

Those averaged percentages for each type of cookie are what I order from the cupboard. I have another chart where I have my possible orders listed by the hundreds and have each type of cookie calculated in both the actual numbers and the numbers averaged to the nearest case, both up and down, so that I don't have to do all the calculating fresh every week. 

So that tells me what percentages to order, but I still need to know how many overall boxes to order. That's a whole other set of graphs!

For that, I took each booth location that we worked last year and broke it down into sales per hour. If we did several booths at that location, I put the graphs all on the same page:

 Notice that this information is less useful when we've gotten a booth spot for a really long period of time. For instance, in the bar graphs above, you can see that when we did a Sunday morning booth there, our per-hour sales were fewer than 20 boxes. But if you just looked at the Sunday where we started there at 10 but stayed all day, our average is over 40 boxes per hour. Some hours in there must have been REALLY good to bring the average up enough to mask the lousy morning sales, but I don't have the information to see where they were.

 If we only did one booth at that location, I put it by itself:

It's a decent start to figuring out sales numbers, but with just one booth spot, you can't rely on it completely.

The per-hour number, then, is a good way to figure out how much to order for a weekend of booth sales. But what you don't see very clearly in the bar graphs is that you also have to take into account how far into the season your booths are. A booth spot the first weekend of cookie sales is obviously going to sell a lot more cookies than that same spot six weeks later. Here's the graph that I made to represent how our sales fell off over time last year:

I think that this graph actually makes it easier to see how the day of the week affects sales, too. And it's certainly a good visual for the kids that extra hustling is likely to pay off better early in the season than later. 

It's a good idea to continue calculating these percentages and sales per hour as you go through the current cookie season, both because the percentages do change a little every year, and I've made some small adjustments to how I'm ordering, and because you're adding new booth dates and times to the information that you have available. This is the best time to teach the kids how to make these calculations and use this information, as well. This is Step 5 of the Junior Cookie CEO badge, but since the whole purpose of earning a badge is to use the skills you learn, older kids could be expected as a matter of course to make these calculations and predictions part of their cookie sale experience every year. 

Today, for instance, it's my older kid's turn to help me. While I'm writing this, she's going through last weekend's booth tallies and calculating the percentages of each type of cookie sold. Next, she'll average that with last year's average to come up with a corrected current average. Finally, she'll multiply by ten to come up with the number of each type that I want to order from council this week, divide by 12 to find the number of cases I'll order, and round down to the nearest whole number so that I don't have to deal with any partial cases. 

Sounds like a pretty good homeschool afternoon, yes? 

P.S. Want to read more about Girl Scout cookie booth math and marketing? Here's my complete series (so far!):

• Girl Scout Cookie Booth Analytics, or, Math Helps Girl Scouts Sell More Cookies!
• My Very Own Girl Scout Cookie Booth Calculator: How Many Cookies to Order for Booth Sales
• Girl Scout Cookie Booth Math: Equal It Out and Assign It Fairly
• Girl Scout Cookie Marketing: Kid-Led and Kid-Made Signage and Campaigns

P.P.S. Want to know more about all the weird math I have my kids do, as well as our other wanderings and wonderings? Check out my Facebook page!