Who Knew Rice Could Be SO Powerful?

Exponents are a fascinating topic to me.  They rank up there with probability in the category of "unexpected answers that make no sense." With exponents students are amazed at how big numbers get and how fast they get there.  I have a number of activities I do to hook them in, but the first one I do involves some rice...

I started with an ancient parable of a farmer in Ancient China.  The parable has many different origins, most commonly in India, but I chose Ancient China because the students just finished a unit on this region and I felt it would be a great way to review the vocabulary and geography of the area. 

The story goes like this...

Once upon a time a farmer found a way to vastly increase the amount of rice produced on his farm.  He shared this information with his Noble who in turn told the Emperor.  The Emperor was very happy, for growing rice was one of the ways to get wealthy in ancient times.  It wasn't like they could just go to Kroger and buy rice, you know.

The Emperor insisted on an audience from the farmer, who showed the next day.  The farmer, being only a peasant, approached his Emperor with his head bowed the entire time.  The Emperor commended his subject and said as a reward he would grant him a reward of a pound of rice a day, every day, for a year.  This was an astronomical amount of food.

We then measured what a pound of rice looked like.  I always keep tupperwares of rice in the classroom - they come in handy for many different activities.  I also got out our science beakers and digital scale.  The pound of rice we measured had just more than 500 ml of volume.  We also estimated there were between 7,000 and 10,000 grains of rice in that pound.  Looking at a serving size, we learned that this would be between 8 and 10 servings of rice by today's standards. 

Doing some more math revealed that at the end of 30 days the farmer would have about 300,000 grains of rice. 

... Then the story continued...

Being a humble peasant, the farmer refused the reward.  Instead, he said, he wished for merely one grain of rice, doubled each day for the 30 day period. 

The Emperor laughed, but was impressed by his subject's modesty.  He granted his wish.

Students then discussed if this was a good plan.  Many of them had heard this story before, and so knew that the farmer made a good choice, but the challenge was to estimate how many grains of rice he would end up with after 30 days.  Estimates ranged from "a few hundred" (from students that had never heard the story) to "about a million." 

So to emphasize the deal I got out the rice again and said, "OK, day 1... ONE grain of rice" and I put the grain of rice on a random student's desk.  "Whew... ok... day TWOOOO.... two grains of rice..." (another student) "day three... four grains! that looks SO FILLING!" (another student.)  I do this through the first 5 days getting up to 16 grains.

Students were then challenged with proving which deal was better.  To do this we decided to use chess boards and post its to help organize our thinking and planning.  Students were put in groups of two or three students to record the results. 

The numbers started small...

... but they started growing...

and kept growing...

Students were shocked at how large the final answer was (over 500 million grains of rice on day 30 alone!)  At the end we did some reflection on exponents. Here are some responses from the closing:

• The numbers start off really small, but got big REALLY fast after like day 20.
• The emperor must have been really upset!
• It didn't seem like a good deal, but on day 19 he already had more than all 30 days from the other deal. 
• That was WAY more than I thought it would be. 
• How many pounds of rice is that??? 

The last part of the assignment was for them to write how the story ends.  What happened to the farmer? Ideally they would use their knowledge of social structures to answer the question (would the Emperor kill the farmer? Honor the agreement? something else?) 

It was a very fun lesson and really emphasized the power of exponents!  

The Amazing (Review) Race

For a final review in term two I decided to host an Amazing Race activity.  This review would use the TV show as inspiration to review concepts in the major content areas.

The students walked in to a dimmed room with the opening theme to The Amazing Race playing on repeat.  We watched a quick clip to help orient students that have never seen the show before and then I explained how it was going to work today.

• Students were on teams of three or four. 
• Each team was assigned a color and symbol.
• Clues for each team were in envelopes with their symbol. 

The Teams

Unlike the actual amazing race, the goal wasn't necessarily to be the first team to finish. Instead it was a point-based game where you can earn points for various tasks:

• Completing a route: 20 points
• Completing a road block: 15 points + points for creativity, quality, and originality
• Bonus points: 5 points each (given at the end of the match, similar to Mario Party)

Students were also told there were ways to lose points.  I really wanted to focus on them working together and using each other as a resource:

• Getting help from an adult or other team: -5 points
• Running or unexpected hallway behavior: -5 points
• If your group is split up / not together: -10 points
• Opening the wrong envelope: -10 points

We also talked about 'sabotage' and how it wasn't allowed (for instance, seeing someone else's envelope and moving or otherwise interfering with other teams.) 

That is a great haiku about China - but you didn't talk about the government... ROAD BLOCKED

After that I put them in their groups and said their first clue was in the commons.  They left the classroom, found their clue and the game began.  

We played a total of 4 route cards and one road block.  The route cards reviewed skills from all the major subjects that my partner teacher and I presented in term two.  To add to the game I bought some programmable padlocks from amazon.  Certain route cards led you to a locker number with a lock. The clue also had the combination to that lock embedded in the clue.  A few groups came up to me for clarification, but when I used the phrase, "is this an official asking for help question?" many of them chose to figure it out as a group rather than lose the five points. 

$10 on Amazon. Great purchase.

After the game was finished, students completed a reflection / feedback survey.  The results were very positive.  Students rated their partner's helpfulness at 3.2 out of 4, Fun rated a 3.3 out of 4 and 93% of students said they'd want to do this again.  It took quite some time to create this, so I'm glad that it went so well!

I really enjoyed this activity for a number of reasons. Students were encouraged to ask each other for help rather than asking a teacher. Only two groups asked a teacher for help throughout the entire game, and that was after they realized they all were stuck.  I got to incorporate a mix of topics - science, social studies, math, and language arts were all represented.  On top of academics, the social pieces - communication, team building, and all the skills that go with that were also emphasized.  I'll be excited to try this again in term three!