Science Buddies: "Ask an Expert"

Our 2nd grader is interested in building a boat lock for his science fair project. We are trying to help him determine an appropriate testable question and would appreciate help. Could it be (What would the effect on boats be if boat locks weren't in place? ie. boats would run aground, longer travel times, economic impact regarding shipment of goods). I'm having a hard time linking it to the boat model itself. Sorry.....science was not my strongest area. Thanks in advance for your help.

love2learn2,

Thank you for your questions and welcome to the forum. The key to any experiment is to try and discover the relationship between one variable that you will change, called the independent variable, and other variables, called dependent variables, that change as a result of changes in independent variable. Another key is that the variables be discrete, measurable, and testable. The things you describe seem to be outside what can be testable for a second grader. Some good info on developing a testable hypothesis and identifying variables can be found in our project guide @:

https://www.sciencebuddies.org/science- ... ndex.shtml

From what I know of boat locks, seldom does a passage have just a single lock to move a ship from one body of water to another of differing elevation. Rather, there is usually a series of smaller locks that gradually move the boat through. The locks then are limited in the size of ship they can accept. For the Panama Canal, this size is known as the panamax standard and many international cargo ships are built to this spec so they can use the canal. There are some current ship designs, like todays supertankers that are just to large to negotiate some of the worlds locks. Ideally you would want your lock as big as possible, but the size and amount of pressure on the lock doors when full becomes too large. Also, the amount of work needed to fill and drain several smaller locks may be less than that required for one huge one.

That being said, i think you could explore those ideas. 1) a design project to see how big a lock can be before the doors fail or 2) how big can a lock be before it takes more energy to operate than two or more smaller ones.

For the second one, i would suggest a scale model of a well known lock, like Panama canal and define an independent variable of lock volume and dependant variable of work required to empty/fill each. So for example is the work required the same to fill/drain a single lock the length, width, and depth required as two half the size, a third the size...etc...

From my research, I find the Panama canal to be divided into 6 stages with total length of 5000 meters with total elevation change of 52.5 meters. This is just the locks, the canal itself is over 7000 meters with all channels and routes combined.

This is just an initial thought and probably needs some refining based on deeper research on lock design.