# Cartober: Challenge 3: How many 50g blocks do you have, Ms. Tice????

Our final challenge for Cartober took the remaining Fridays in the month of October.  The first step was making a car that would have a place to carry up to ten 50 gram Lego blocks.  We raced the cars down our ramp in a hallway where the cars could roll as far as possible.  We used rulers to measure the distance each car rolled.

Kids worked in groups of 3 to build their cars.  Once we were ready to start racing them down the ramp and measuring the distance, the kids picked “jobs”.  One kid needed to be the Measurer, one needed to be the Recorder, and one needed to be the Racer.  They would switch jobs with each trial, so that each kid had a chance to measure, record, and race.

The first trial was just the car by itself with no 50 gram blocks.  Each group raced, measured, and recorded.  If a car broke on the way down, the group was allowed to go fix the car.  On the second trial, we added one 50g block.  On the third trial, we added five 50g blocks, and on the fourth trial we added ten 50g blocks.

The building of the car and doing the four trials were not done on the same day.  We split it up so that the kids built a car and raced it with no 50g blocks to get their initial measurement on the first day.  Then we placed the cars in gallon-size ziploc bags and I wrote each group’s names on the bag.  The next Friday, we finished the trials.

After all the trials, we reflected on the effect of the added weight to the cars’ distance.  We talked about what this could mean.  Many kids said they were surprised that the weight would make the cars go so much faster.  They had predicted that the weight would slow the cars down.  Several kids remembered a field trip they took to a local ski resort in second grade to go snowtubing.  They made the connection that it made sense that more weight would make something go faster because when you snowtube, you go farther if you connect more tubes together.

The kids loved Cartober and were sad to see the car racing come to an end.  Little do they realize, but this will not be their last car race…. MUAH HA HA HA HA!

# Cartober: Challenge 2: The Gingerbread Man’s Great Escape

Since we are calling October “Cartober”, all of our Challenge Friday challenges are related to cars and the simple machine wheel-and-axle. Each challenge during the month of October builds on the challenges from previous weeks. We are also in the middle of a Fairy Tale unit in our language arts classroom, so I wanted to find a way to combine Challenge Friday, Cartober, and fairy tales! The challenge this week: find out what makes cars go faster and build the fastest car possible!

We started by reading the classic story of The Gingerbread Man. We talked about the elements of a fairy tale that the story included, just as we had done for all the other fairy tales that we had read during the unit. The kids noticed something important about the ending of The Gingerbread Man – that it didn’t end with a “happily ever after” for the gingerbread man. They noted that this was unusual for a fairy tale because most of them have happy endings. This led us to the challenge.

I told the kids that we were going to rewrite the ending so that the gingerbread man does end up happy instead of eaten. We called it The Gingerbread Man’s Great Escape. I told them that they would have to make a car like last week for the gingerbread man to make his getaway, but they would have to make the car go as fast as possible, and they would have to think like a scientist to do it.

First we brainstormed ideas for things that could possibly make a car go faster. The kids suggested things like more weight, less weight, bigger wheels, smaller wheels, using Lego pieces with holes so that air could pass through easier, and using wheels that spin easily.

Next I told them that they should try any of those modifications to their car to find out if it really does make the car go faster. I asked them how they would know scientifically that the car was actually going faster. I asked, “Will you just watch and guess whether or not it’s actually faster? Is that what scientists do?” One student suggested that we record something. I asked what exactly we would be recording. Several students shouted out, “Speed!” I asked them how we would do that. “What device do we have that records speed?” They couldn’t think of anything. Another student suggested that we could time the cars as they go down the ramp. Again, I asked what device we would use for that. We ended up using the stopwatch feature on the iPod touches.

The last conversation topic that we had before we started building and racing was about the idea of changing only one variable at a time. I asked them what would happen if they added weight, put on bigger tires, AND used a piece with holes, and the car went faster. How would they know which thing made the car go faster? They realized they wouldn’t be able to tell. So I reminded them to change only one thing at a time and then record the time before trying out another idea. I gave them each a little Lego gingerbread man figure to put on their car to help him escape from the fox!

The kids set to work right away and tested out ideas, recording the times as they went. It was interesting that many of them still had misconceptions about what exactly they were recording. Some would come to me and show me the time on their stopwatch and say, “Look at the speed now!! It’s way faster!” They were equating time with speed. Others needed help understanding what “1.6” means as a number.

Finally we met in a share circle to explain our results and conclusions to the rest of the class. Most kids came to the conclusion that adding more weight made their car go faster. A few came to other conclusions. We talked about the adding more weight and what effect it has on a car. This was an important idea because it has to do with their final challenge of the month. Then they recorded their conclusions on a reflection sheet that they glued into their notebooks.

# Cartober: Challenge 1: Make a Fast Car

We are renaming the month of October “Cartober” because all of the challenges this month will be related to cars, speed, force, and gravity. The first challenge was very simple: build a fast car.

I went to Lowe’s expecting to buy materials to build a ramp with three or four lanes for the cars to race down. I went down the aisles, pricing the plywood and other materials I was going to need to build this ramp. I also became aware of the amount of time I was going to need to build it. I vaguely played with the idea of having the kids build it instead of just me. As I passed the aisle with siding for houses, I noticed a particular piece of siding that was super long and was molded in the shape of three lanes on the underside. How perfect! \$12 and I had the perfect bendable three-lane ramp with no other prep work necessary! I was super proud of myself!

On Friday, I explained the rather simple challenge to the kids. They simply had to build a car that would travel down the ramp successfully. This particular challenge was not meant to be difficult because the challenges coming up for the rest of this month are meant to build on the basic idea of making a car. We talked about another simple machine, the wheel-and-axle, and I drew another diagram to label the parts. We also reviewed the previous two simple machines that we had used in earlier challenges – the lever and the pulley.

When the younger students came, I explained the task and read a story to everyone out loud. It was a picture book called Roy Makes a Car. All the children loved the book! They thought it was funny and it was a perfect interest level for first to third graders.

The kids partnered up and began making their cars. They had 20 minutes to build, test, and modify their cars. We discussed new vocabulary like modifications. Finally after 20 minutes, I rang the chime to announce that the races would begin. We allowed the first and second grade partners to race the cars first so that they could head back to class after racing. Three kids could race at a time. The third grade partners collected their cars at the bottom and waited patiently for their turn to race.

After everyone had a chance to race their cars, we met in a circle for reflection time. I asked the kids what part of their car they liked the best and what they would change if they had more time. It was interesting to hear some of the ideas of things they would change. Several kids said that they would remove blocks to make it lighter because, “heavy cars go slower.” This was a common misconclusion and it leads perfectly into next week’s challenge. We will be using the scientific method to determine what actually makes a car go slower or faster. The final part of this week’s challenge was using an app called Tellagami on the iPod touches. The kids took a picture of their car and made a short video describing the things they liked about their car and/or what they would do differently next time.

Everyone had a great time and they seemed to really enjoy working with kids from different grades. When I checked in with the second and first grade teachers later in the day, they reported that their kids had come back from the experience saying it was the best day ever!!

# Making a Dumbwaiter

This challenge connected our field trip to Monticello and our learning about Thomas Jefferson with simple machines. We had seen the dumbwaiter that Thomas Jefferson made in his dining room to bring wine bottles up from the cellar. When we were at Monticello, I told the kids to pay careful attention to the dumbwaiter because they were going to have to make one the next day for Challenge Friday. Their immediate reaction: “Are you kidding??? How are we supposed to do that???” and “Um, you’re going to give us more pieces, right?”

On Friday, we began the discussion by remembering the dumbwaiter that we had seen the previous day. We talked about what purpose it served and how it worked. I showed the kids a quick video on youtube about how pulleys work. I showed the video in English and in Spanish, because I have a student who just moved here from Honduras and speaks only Spanish. Then I drew a diagram of a pulley on the board and had the kids help me label the parts in English and Spanish – wheel, axle, rope, load, and effort.

Then I showed the kids a little Lego minifigure I have of Thomas Jefferson. (I think it’s really some random revolutionary war soldier, but it serves the purpose fairly well!) I also showed them the additional pieces I had added to each of the challenge bags: a chain to act as the rope, a golden goblet to be the bottle of wine, a wheel without a tire (so there will be a groove for the chain to fit in), and an axle for the wheel. All the other pieces from previous challenges remained the same.

The kids set to work immediately building a pulley system and platform that would lift the golden goblet up to the table where Thomas Jefferson sat. When questioned on the parts of the pulley, they could accurately identify the axle, wheel, cable, load, and effort. I had them work with partners again, explaining that I really wanted them to continue having the experience of working through shared ideas, disagreements, and compromise.

In the end, all partners were able to build a simplified version of a dumbwaiter successfully. They had fun with little Thomas Jefferson receiving his wine to take with his dinner!

# Engineers Use Catapults to Defeat Lego Trolls!

This week’s Challenge Friday was related to the lever challenge from two weeks ago. We began by reviewing the parts of the lever and how levers are used. Part of our third grade curriculum covers Ancient Greece and Ancient Rome, so next we read about one of the ways that levers were used in Ancient Greece. We read about an Ancient Greek invention – the catapult! We had a conversation about what catapults were used for, how they were made, and what their advantages and disadvantages were. That led to the challenge of the day.

CHALLENGE: Lego knights are being tormented by two trolls! Due to their strength and size, the knights’ swords and spears are powerless against them. They are seeking help from some local engineers to design a stronger weapon to defeat the trolls. Design and build a catapult that will launch a cotton ball “boulder” at the trolls exactly one foot away.

The kids immediately set off to build their catapult. They were given a ruler and recording sheet to measure the distance the cotton ball traveled after each test launch. Many of the children remade their lever from two weeks ago and then modified it to work as a catapult. Some completely changed their lever designs to make their catapults more effective. When they were confident that their catapult would hit a target exactly one foot away, they brought their catapults to me and tried it out against the Lego trolls. The tension was high as they would set up their catapult with the cotton ball “boulder.” Would they defeat the trolls? Some kids got it on the first try! Others missed and went back to make further modifications. Each time they returned, I asked them what changes they had made and why.

The kids were completely engaged and desperately wanted to make their cotton ball hit the trolls! There were several problems when kids were picking partners, however, where one child would whine about another student picking them to be a partner. This coming week, we’ll talk about how to be fair partners and how to be careful with reactions to being picked so that it doesn’t hurt others’ feelings.

# Sundial Machines Under the Sidewalk

In the front of our school, we have a big sundial painted on the front walkway outside. It was painted on the sidewalk and it’s really neat! There’s a box that says each month and if you stand in the box of the month that we’re currently in, your shadow will point to what time it is! After lunch, we walked outside to check what time it was according to the big sundial. The kids each stood in the “September” box and saw that their shadows pointed almost at the 12. They asked me what time it really was and I showed them my phone – 11:55. There was a chorus of “Wow!” and “Awesome!” and “How does it do that????”

When we got back to our classroom, we sat down and I asked the kids how they thought it works. “How does the sun cast a shadow to exactly the right number?” Their answers were very funny and showed definite understandings and misunderstandings of the way the sun and Earth are related. Here are some of their guesses:

“I think it’s because the sun knows what time it is so it puts the shadow at the right spot.”

“Maybe there’s a giant machine under the sidewalk that controls the shadow to make it go the right way.”

“The sun makes a shadow on the ground and as the sun moves across the sky your shadow changes.”

We talked about it a little more and then I asked them another question: “Why do you think there are different boxes depending on what month you’re in? Why can’t there just be one box and we always stand in that box?” Again, many responses, many ideas…

“Well, you know how it’s a different time everywhere in the world? Like in Japan right now it’s night. So maybe it matters what box you’re in because it matters where you are in the world.”

“I think it’s because the sun rises and sets at a different time in the year. Like some days are shorter and some days are longer. Like right now it might be a short day but in October it’ll be a long day and then a short day.”

“Yeah, I think she’s right because I go to afterschool and when my mom picks me up right now it’s still light outside but in the winter, it’s almost dark when she picks me up. I think it matters how much daylight we have.”

I loved listening to their ideas of how the world works and why they think things happen the way they do. It’s clear that some of them have heard/read/discussed some information about the sun and Earth, light and time. It’s interesting how they take everything they learn and try to make sense of it! We did finally google it because they were begging me for the real answer of how that simple, yet complex sundial works. They were very proud that they at least got a few parts right!