Hook
15 min.
Talk about the history of water clocks. http://en.wikipedia.org/wiki/Water_clock
Relate this to how the Greeks used the water clock to limit debate in public life.
Discuss how the Greeks divided the day into 12 hours, so they changed length as the seasons changed.
Show the Tower of the Winds in the Agora. http://en.wikipedia.org/wiki/Tower_of_the_Winds
Lesson Flow
10 min - Divide the children into groups. Ensure each group has a heterogenous mix of students. Introduce the experiment. List required information to be gathered for the lab report.
30 min - Allow the children to gather data.
5 min - Cleanup.
10 min - Demonstrate how the produce a scatterplot.
30 min - Allow children to do their scatter plot. If they finish early, have them consider the remaining questions on the Experiment sheet.
15 min - Discuss remaining questions as a class.
Teachers Notes:
p = a*h, where a is a constant (density*g) and h is the height of the water column.
Flow = b*p where b is a constant.
So theoretically, they should get a linear graph ending at zero. Realistically, surface tension will mess this up when you get below a couple of cm of water.
Key Questions:
What is a siphon, Why do you need different clocks for different seasons. Why does the sun move north to south.