A few days ago I posted a photo of the poinsettias that Ginny installed in the front atrium. It rained today and we were surprised at the beautiful raindrops on the leaves. Also being chemists we noticed the contact angle of the drops. In simple terms it means the water beads up on the surface just like water beading on a freshly waxed car body. This is a phenomenon related to surface energy and contact angle. The liquid and the surface interact which is important in many applications. It is often referred to as wetting. You want low contact angles for good wetting (like paint) and high contact angles for beading up (waterproofing). One practical driving application is RAIN-X windshield washer fluid. It treats the glass to reduce the surface energy thus causing the water to bead up. I use it all the time. At highway speeds the rain beads up and runs up the windshield thus keeping it clear enough to see easily. Many times I don't run the wipers because the drops just keep going up and out. So I hope you enjoyed this little chemistry lesson. I certainly did.