How to teach algebra to the children (part 2)

In this experiment, you will do an experiment to test some of the principles involved in building bridges.

Equipment : several A4 of paper, two books of the same thickness, a small plastic cup, and about 50 pennies.

Directions :
1. Make a paper "bridge" by folding up 2 cm on the each long side of one of the paper strips.
2. Suspend the bridge between the two books. The bridge should be overlap each book by about 1 cm. Place the plastic cup in the center of the bridge.
3. Put pennies into the cup, one at a time, until the bridge crumples. Record the number of pennies you added to the cup. This number is the "breaking weight" of the bridge.
4. Put two strips together to make a bridge of double thickness. Find the breaking weight for this bridge. Repeat this experiment to find breaking weight for bridges made from three, four, and five strips of paper.

Questions :
Before answering the questions, you have to make a table and draw a straight line on a grid paper that seems to fit the pattern in the (thickness - on the horizontal axes, breaking weight - on the vertical exes) data you graphed.
1. Based on your graph model, what breaking weights would you predict for bridges 6 layers thick and 7 layers thick?
2. Suppose you could use half-layers of paper to build the bridges. What breaking weights would you predict for bridges 2.5 layers thick and 3.5 layers thick?
3. Could you make an equation that related between layers thick (x) and breaking weight (y), which is the equation would be y = mx + c ? Where : m is the slope or gradient and c is constant or y-intercept on the graph.