Measuring water purity

This week we showed our interview with one of the chemists, Joel, working at Encina Wastewater Authority in Carlsbad, CA where they treat wastewater so that it can be returned to the ocean. Water samples are tested for the amount of suspended solids as it arrives at the facility and at various stages throughout the treatment process. Joel showed us how he determines the level of solids, measured in milligrams per liter, and what math he does in the process.

The incoming water typically measures between 200 and 400 mg/L, and it leaves the facility at less than 5 mg/L before it heads to the ocean. That's a 99% reduction! 

We also mentioned the March Madness men's college basketball tournament beginning tomorrow. Many organizations offer cash prizes if you correctly predict the winners of all the games (there are 63 games in the tournament). One site is offering $12 million! Are they confident they won't have to award any money? Probably! On the program, we showed the astronomical odds of correctly picking all the right winners. No one has done it yet! Here is an interactive bracket you can fill out for fun on ESPN's website.

new contest!

As described above, we have a new contest running. You may need to use a little algebra! If you figure it out, you can be our official winner by calling us and giving us your answer on our next live broadcast (March 18). The phone number is (888) 762-1489. Good luck!

Ocean waves

On this week's broadcast we discussed many ways in which mathematics is used in the study of the movement of water in the ocean. It turns out that this is a pretty complicated issue. There are partial differential equations that are used to describe fluid flow, but solutions to these equations have been elusive thus far. Computers are used to estimate approximate solutions with research continually done to improve the results.

We also talked about how water waves resemble the graph of the sine function from trigonometry. A more accurate model is a "trochoid," the path formed by a point on a wheel as the wheel rolls along the ground. Both the sine graph and trochoids are based on circular motion which isn't too much of a surprise since ocean water actually moves in small circles as the shape of a wave moves across the surface.

For further information check out these links.

animation of ocean wave

Wikipedia entry on ocean waves

detailed article from SIAM on mathematics and the oceans