Above is the Palace bridge spanning the river Neva in St. Petersburg Russia. Bridges that span shipping lanes must be high enough for tall ships to pass under or have some capacity to open and allow tall ships through. London bridge is another famous bridge that opens to allow access to large vessels.

Research five other bridges, from around the world, that open by hydraulic devices. Present your finding as a PPT presentation. In your presentation you should consider:

- Historical reasons why the bridge was built.
- Reasons why it has its unique design.
- A picture of the bridge, identifying the type of bridge that it represents.

Construct the lightest strongest bridge using icy-pole sticks and or skewers. You must be able to raise the bridge, at least 45 degrees to the horizontal, to allow vehicles or vessels to pass underneath. The lifting mechanism must be hydraulically operated.
The Model will be assessed according to this rubric.

Hint- Use syringes and aquarium tubing.

The bridge must span a distance of 30 cm and be 4 cm wide. The height of the bridge is left up to you. The strength of each bridge will be tested by placing weights in the middle of the bridge. The maximum weight that the bridge is capable of lifting, is divided by its total mass. This figure is used to calculate the winner. The highest score wins. The minimum weight the bridge should support is 5.0 grams for 5 minutes.
Score = total mass (grams) / mass of bridge (grams)

Here is one model that was submitted.
Click to see a video.

The image on the right shows a variation on the lifting mechanism. Notice how the syringes are inserted.
Click to see a video.