June

Take the challenge...


Surface tension lets insects walk on water

Some Delta insects, such as water striders, use surface tension to walk on water. Here is a simple experiment you can try at home to see how they do it.

First, fill a large cup with water. Next, gently lay a paperclip on a small piece of paper towel, then place the towel with the paperclip on it on the surface of the water.

The paper towel will sink, leaving the paperclip floating on top of the water.

Now put a drop of dish detergent in the water. This will bind with the water molecules, interfering with the surface tension. The paper clip will sink. The detergent disrupts the molecules and breaks the tension.



Take a look back to 2015...

First explorers not impressed

High in the hills surrounding San Pablo bay, Father Juan Crespi got his first glimpse of the Delta in 1772. The river had swelled from heavy spring rains, making the area inaccessible and leaving Crespi with the impression that it would be a poor location for a mission. Just four years later, in 1776, explorer Juan Bautista de Anza came to the Delta area and saw something completely different. From his observations de Anza decided the region was just an inland sea and a perfect area for a settlement. During the Gold rush of the 1850s, the Delta was a busy route for miners making their way from San Francisco to the Sacramento hills to find their fortune. Many later settled on Delta islands and built farms, making their fortune on crops.

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