Marble Roller Coasters - Going Further ...

As I predicted - the students LOVE this project. We began with making roller coasters in Minecraft but there are quite a few things about Minecraft that just don't work in the real world. Now we are on to making Marble Coasters on the walls of the classroom.

Here is an explanation from Science Buddies.org behind how a Roller Coaster works:

Slow and clanking, the string of cars is pulled up to the crest of the tallest point on the roller coaster. One by one, the cars start downhill on the other side, until gravity takes over and the full weight of the train is careening down into curves, twists, and turns. The roller coaster is a great example of conversions between potential energy (stored energy) and kinetic energy (the energy of motion). As the cars are being pulled up to the top of the first hill, they are acquiring potential energy. The chain that pulls them up the hill works against the force of gravity. At the top of the hill, the cars' potential energy is at it's maximum. When the cars start down the other side, this potential energy is converted to kinetic energy. The cars pick up speed as they go downhill. As the cars go through the next uphill section, they slow down. Some of the kinetic energy is now being converted to potential energy, which will be be released when the cars go down the other side.

You've probably noticed that the first hill on the roller coaster is always the highest (unless the coaster is given another "boost" of energy along the way). This is because not all of the potential energy is converted to kinetic energy. Some of the potential energy is "lost" in other energy conversion processes.

You can investigate the conversion of potential energy to kinetic energy with this project. There are as many possible variations to this project as there are twists and turns on a great roller coaster ride, but a good place to start is to see how much initial height you need in order to have your marble successfully navigate a loop in the track.

You'll use the same size loop for each of your tests, but you'll add (or subtract) track before the loop so that you can change the initial height where the marble starts. For each track configuration, you should try at least 10 separate tests with the marble to see whether it can loop the loop or not. You should also measure the slope of each track configuration. An easy way to think about the slope is the expression rise/run (see the illustration below). The rise is the height of the starting point, and the run is the horizontal distance from the starting point to the beginning of the loop.

The illustration above shows how to measure "rise" and "run" in order to calculate the average slope of the track leading in to the loop.

How much height (rise) will be required to successfully navigate a given loop size? A foam roller coaster for marbles is easy to build, so try it for yourself and find out!

Oh oh - I did it again Grade 5 ... my lesson turned in a Maths lesson ...

So you will need to measure the height (rise) and the run (length along the bottom) of your first hill run on your coaster.

I wonder how these numbers will compare? My challenge to you is to make a successful loop de loop.

Designing a Community Building for the Serpong Landfill

5MJ have begun putting into action their intent to build a community building for the Serpong Landfill. They are starting to create a design for a community building. First the students talked about the building and what it could be used for. The class decided that they could probably raise about 3 million rupiah by holding some market days.

Next the class worked with Ms Agnes to measure the two traditional buildings in the SWA playground.

In class the students sat in the shared area to try to decide how big the building needs to be. We decided that 4 meters by 5 meters could fit about 20 people comfortably and possibly come under our budget of 3 million rupiah. But we don’t know for sure …


Now that we have the dimensions, the students created a detailed drawing for homework. In the meantime we have started working on the design in Sketch Up. We have been really using our geometry skills. In Sketch Up we learned about components, using the protractor, measure the sides accurately, rotation, alignment, axis and units.

After thinking about it. Ms Jane decided that Google Sketch Up wasn’t working because the students didn’t understand the concept of form. The students needed to work in 3D. Sketch Up is working in virtual and the students really needed to understand 3D by touching and seeing it in front of them. We needed to try to build it …

Today in class we started making structures using bamboo chopsticks. Ms Jane bought a lot of chopsticks so that we could learn about the form. Together with a partner, we began making the structure.

It was fun and very challenging! All the students have written a blog post about what they did and what they learned.

Measuring an Accurate Circle

When the Solar Bulb group of students wanted to mount a coke bottle into a rigid piece of cardboard, they came up against a problem that they tried hard to solve by themselves. How can you make the hole the right size if you have a bottle and you cannot measure the it’s diameter. The idea they came up with to solve the problem was after much discussion…but was it accurate!


It looks simple to embed a coke bottle into a sheet of plastic ... but how do you measure the circle accurately?

Does the diameter equal half of the circumference?

How can you work it out? Is there a Mathematical formula that can help you?

Below are the calculations that Grade 5 came up with.

What we wanted to find out was - Does a = 2b? a is the circumference and b is the diameter.

How Did People Measure Rice Fields in the Past?

Today we discussed how rice fields used to be measured. Ms Jane’s husband told her that in the Batak villages in North Sumatra the rice fields would be measured in depa.

One depa is the distance between your wrist and your elbow.

You measure by using string (raffia) and winding the string around your arm.
Cupak is used to measure the volume of rice. One cupak is one half coconut full of rice.

Did you know that your foot is approximately the length between your wrist and your elbow?

SWA Soccer Field and a Rice Farm – Which is bigger?

Today we sorted out our Math problem for measuring the SWA soccer field.

We had a small competition to see which group got the closest measurement to the actual size.

The size of the SWA soccer field is 4,000 m²

Group 3 (Shereen, Gabi, Zubin and Rifqi) had the closest answer which was 3,969 m²

What we realized was that the average size of a Javanese rice farm in Indonesia is smaller than the school soccer field. The average rice farm is 3,333 m². Most of the Grade 5 students thought that the rice farm would be much bigger. It was a shock for us to realize this. We now know that the rice farms that we can see are often several rice farms joined together so therefore have more than one owner. It is now not surprising to us that the farmer will only make 9 million rupiah per year based on getting two harvests in a calendar year. This is not enough to live on as this gives the farmer less than US$100 per month to feed their family.

Take a look at our video to see how we measured the school soccer field. It was not work but a lot of fun!!

Visualizing the Size of a Rice Farm in Indonesia

This is the SWA soccer field. Is it bigger than the average Javanese rice farm?

Here are some students ready to measure the school soccer field.

Today 5MJ had the task to measure the area of the soccer field at SWA. The students have been learning about area. This is a part of our inquiry into the size of a rice farm in Indonesia. We have learned that the size of an average Javanese rice farm is 3,333 square meters. The purpose of measuring the soccer field is so that the students can compare the size. They cannot image how big 3,333 square meters is, so once we know the size of our soccer field we can see if the rice farm is bigger or smaller.

We got our information about the size of rice farms in Java from detik.com.

This morning each student made a drawing of the soccer field and put a drawing of how big they thought an Indonesian rice farm would be next to it.

Shereen makes her prediction. She thinks that the average Javanese rice farm is much bigger than the school soccer field. Look at her prediction drawing on the mini white board. She then captured this with her Photobooth and uploaded it to her blog. Read Shereen's post.

How Much Land Does a Rice Farmer Have in Indonesia?

Today we researched about how much land does a rice farmer have in Indonesia. We found the answer on Detik.com

"Di Pulau Jawa, rata-rata petani hanya memiliki 0,3 hektar sawah. Seandainya satu hektar sawah bisa menghasilkan lima ton gabah kering giling, berarti mereka hanya mendapat 1,5 ton gabah sekali panen. Jika dalam setahun terjadi dua kali panen, mereka hanya memperoleh tiga ton setahun. Itu setara dengan Rp 9 juta per tahun, atau kurang dari Rp 1 juta per bulan."

We copy pasted the answer into Google Translate. Here is the translation:

"In Java, the average farmer only has 0.3 hectares of rice fields. If one hectare of rice can produce five tons of dry unhulled, meaning they only get 1.5 tons of grain at harvest. If it occurs twice in a year of harvest, they only get three tons a year. That’s equivalent to Rp 9 million per year, or less than Rp 1 million per month."

The students converted the answer into square meters by making a long division using a small whiteboard.

Inquiry Into Life on a Limited Budget

My class 5MJ has just started a new unit of work. The theme is Sharing the Planet and our focus is about resources and how they are not equally shared in the world. This is particularly the case in Indonesia.

This morning 5MJ were given a task to follow up their front loading done last week. In that activity the students were asked to work out how they could buy a meal for four people with Rp. 14.000. The students thought that it was impossible, so today we decided to inquire further.

FINDING OUT

The students worked in groups. They brainstormed what kinds of food they could buy and recorded the questions asked by the group as they tried to find out. Each group found that they had more questions than answers.

STUDENT INQUIRY QUESTIONS

Where can we buy the food? (Jinny)

Is 14,000 enough? (Bernhard)

How much money do we need to get us to BSD and Jakarta? (Regina)

Where can we find food that is cheap and near to BSD? (Keaton)

Where can we find food that is less than 14,00o? (Jessica)

What food can we buy with only 14,000? (Regina)

How much is a meal for a person? (Jinny)

Is bread enough for eating in one meal? (Gabi) – Can we just eat bread for this meal?

How long does the big aqua last? (Gabi)

What different foods are cheap? (Shereen)

What if the person can’t even buy the food? (Gabi)

How much is tempe? (Zubin)

What is the price of something cheap to drink? (Lisa)

How much nutritious food can the people with less money eat? (Shereen)

What kind of foods are too expensive for people who have less money? (Shereen)

Can you just live on water? (Zubin)

Each group asked their group members about which food they eat the most of every day. In each group, rice was the food that was eaten the most. We agreed that we needed to include rice in this meal that we are trying to plan.

Ms Jane shared a video that she took last night when she went to a warung (small shop) to buy rice. Ms Jane bought 3 kinds of rice, Rp. 6.200, Rp. 6.500 and Rp. 6.800.

We took at look at each of the three liters of rice that was purchased and compared them. We wondered how much does it weigh? Each student made an estimation after feeling the weight.

Many students talked about how much rice they cooked at their house and where they bought the rice.

Next we decided to COOK the rice. We had a big discussion about how to cook the rice. Jinny was the only student who knew that you had to wash the rice before cooking it. We decided to make three groups of four to work together to cook the rice. Ms Agnes had bought her rice cooker to school for us to use.

We need to find out more …. we wondered how much rice costs at a supermarket.

And then we wondered …

How is rice distributed across the world?

Our current UOI is ‘Sharing the Planet’ and our central idea is:

“It is our shared responsibility to ensure resources are more evenly distributed.”

Gabi found a great website http://irri.org which is the International Rice Research Institute. From the website we can learn about which countries consume the most rice in the world. Here is a pie chart showing which countries consume the most rice.

Image from: http://irri.org/knowledge/publications/rice-today/maps/who-eats-the-most-rice

So, back to our first inquiry …

How can we make a meal with only Rp 14.000 budget?

Jessica had a great idea! She asked, “Why don’t we make fried rice with the rice that we cooked today?” We agreed that this might be possible with our budget of Rp. 14.000. We know that one liter of rice can cost as little as Rp. 6.200.

Now the class is looking into what ingredients are in fried rice.

Some of the students said that eggs are in fried rice. Ms Jane shared a video that she took last night at an egg shop in the village. To buy the fresh eggs it costs Rp. 13.500 per kilo. I wonder how many eggs are in one kilo?

(video coming soon)

We must decide who will being which ingredient and that person must know the price of that ingredient.

Everyday Mathematics Estimation Challenge

Today 5MJ took on an estimation challenge during Maths time. The students were asked to locate the Koi building at SWA using Google Earth. Then they were asked to locate Pasar Modern in BSD City. The challenge was to estimate how many kilometres are between the Koi building and Pasar Modern.

After making the first estimation, the students were asked to calculate how many steps it would take if they were to walk from the Koi building to Pasar Modern. We decided that we take two steps in a meter so if one kilometre equals 1000 meters then it will equal 2000 steps.

Here is an example made by Keaton.