What type of support makes bridges hold the most weight?

BIG IDEA

Engineering strong bridges.

FOCUS QUESTION

What type of support makes bridges hold the most weight?

PREDICTION/ HYPOTHESIS

• If we lay our markers down on their side, then our bridge the bridge will be strong but bumpy.
• If we have support in the middle the bridge will be strong
• If we turn the markers long ways it will be stronger, like a road

PLANNING
Materials  
markers
note cards
washers
bags with coins
washers as weights   

First we laid the markers down on their side, close together.

Next we used washers on the edge of the markers to keep them from rolling away

Then we turned the markers to lay on their side so they were the same length on the card.

DATA

Markers	Marker Position	What happened?
6	On their side, perpendicular to the notecard	Makers rolled away
6	On their side, perpendicular to the notecard with washers on the side.	Supported the lighter weight, not the heavier weights.
4	On side, markers long way, with washers on the side	Supported the most weight

CLAIMS AND EVIDENCE

Claim	Evidence
If we lay our markers down on their side, then our bridge the bridge will be strong but bumpy	The bridge was bumpy and strong before the markers rolled away.
If we have support in the middle the bridge will be strong	The support in the middle of the bridge did make it strong.
If we turn the markers long ways it will be stronger, like a road	This was the strongest bridge once we added the washers to the side to keep the markers from rolling away.

CONCLUSION/REFLECTION

In this investigation we learned that supports running in the same direction and the same length as bridge, like our last trial, provide the most support. We also learned in our second and third trial that support on the side of a bridge like the washers make a bridge stronger.

QUESTIONS   

What type of support is used underwater to support bridges?

Are underwater supports made of different materials that are used for bridges over ground?

What material is most commonly used on bridges above ground?

How have bridge materials changed over time?

How do you know if a bridge is going to fall or is still strong?