Caution: Men At Work!

The thing about kids is you never know what is going to happen until you actually try it. Take this investigation, for example... I thought it could either go really well, and the kids would get really into it, or it could go really bad and they would have no idea and it will all be a waste of time. Sometimes you've just got to bite the bullet and give it a go.  In this case - it went both ways... what I wanted them to do was similar to what they did, but their version of it was just as fun!

So my thought process was this. The other week we did the "Build A Bridge" experiment.  It went really well with E, but not so well with N. He was a little young to understand the concept of "Design and Make". That being said, it has renewed his interest in bridges and always talks about them now. So I wanted to do another investigation that involved bridges.

What you need:

• 3 or 4 pieces of Cardboard or thick paper - each one folded a different way.  One was just a flat strip of cardboard. One was a corrugated piece (zigzag).  One was an arch (you can see a better example of the arched bridge we used in  another picture.  The final one was a girder shape (picture of the girder shape is next to this picture).   

 

• 2 cups the same size
• Plastic counters to act as "cars" ... We started off using beads (with flat bottoms), then changed to slices of carrots

First I showed the kids how the two cups were the pylons for the bridge.  I asked them to use the cardboard pieces to build a bridge that holds lots of cars.

Here's how it went...

 

They used each piece of cardboard separately first, then placed the beads on their bridge to see if it would hold.

 

The more beads or carrots their bridge held, the more excited they got. 
However, the more beads their bridge held the more likely they all fell off so we had to change our "cars".  We decided to use chopped up carrot pieces instead!

(I like to think of this as a creative cheat! hahaha)!

The sticky tape came out and pretty soon they were both creating their own bridges using a few of the different examples I had given. They both worked out that the bridge was sturdier if they put on lots of layers of cardboard rather than just one. 

 

By the end of it, the kids had built lots of bridges but then became hungry... and suddenly the carrots disappeared ;)

How is this science? The strength of something isn't just about what it is made up of - the shape is important too.  Folding flimsy card into a beam makes it rigid and strong.

The corrugated bridge is made up of triangle shapes which are the best at holding heavy loads.  A triangle is really strong as it directs weight straight to the ground.

Thank you, Mini Scientist In The Kitchen (Lisa Burke) for this wonderful idea!