Finally! Crossroads at Big Creek has morphed into an enchanting snow-covered winter landscape, and while we continue with our education and restoration efforts, our attention now turns to sliding. Sliding is defined as "moving smoothly along a surface." And while we fervently hope nobody slides off a snowy road or slips on the ice, when conditions are adequate, we will groom selected trails so our visitors can move smoothly on our trails using skis, sleds, and kicksleds.
Months ago, the topic "Sliding" was chosen for this week’s Saturday Science family program. Geared for elementary students but open to learners of all ages, the program introduces the basic physics that enables winter sports. Participants also will learn a bit about the otters that live in The Cove Estuary and, through videos, demonstrations, and (conditions permitting) outdoor experiences, learn about how gravity, force, and friction influence smooth movement.
But wait. There's more.
Scientists are beginning to understand that "sliding" involves more than force and friction. It is difficult to slide on a bumpy or soft, fluffy surface. A groomed trail is solid, and a ski is solid, and though both are essentially smooth, one would expect friction. But skis slide.
So, what really makes snow and ice slippery? The answer: Water.
There almost always is a very thin film of water---sometimes called a "quasi-liquid layer"--- on the surface of snow and ice. Water can be a solid, a liquid, or a gas, but no matter what form, the substance is the same. Water comprises molecules, each consisting of one oxygen atom and two hydrogen atoms. H2O
The different states of matter are due to the amount of energy each molecule has. In the liquid state, water molecules vibrate more than in solid ice.
On snow—fluffy or groomed-- an extremely thin layer of water exists because the water molecules at the surface, for various reasons, vibrate and move more than those more profound in the snowpack or solid ice. The water molecules at the surface tend to be liquid even when the temperature is below the official melting point. And water (even a microscopic film) is slick.
This phenomenon explains how we offer environmentally friendly winter sports. It also enables our river otters to "toboggan" over the snow and to create slides into The Cove Estuary.
So, exactly what is an estuary? That will be explained in a lecture offered on Monday, February 24, at 1:30. The talk will cover the geological and human history of The Cove and discuss the wildlife that use estuaries for breeding and migration.
The lecture will be ”Native Shrubs for a Door County Landscape” on Tuesday, February 25, at 6:30. Jason Feldman of Jason Feldman Landscapes will recommend shrubs that help pollinators and birds thrive in the various soil types in Door County. This free presentation is Co-Sponsored by Door County Master Gardeners (DCMGA) and Wild Ones—Door Peninsula.
The trails at Crossroads are open 24/7, and when conditions are adequate, we also offer Ski-for-Free, during which we lend skis, boots, poles, snowshoes, and kicksleds to Door County residents and visitors free of change. Watch the ticker at the top of the Crossroads website, http://www.crossroadsatbigcreek.org, for trail conditions and Ski-for-Free hours of operation.
Saturday, February 22
2:00 Saturday Science: Sliding
This program, geared for elementary students but open to all ages, will explore the science of sliding, which involves gravity, friction, and other forces that affect how fast and how far a sled, skis, or a kicksled can move across the snow. Outdoor demonstrations, weather permitting. Meet at the Collins Learning Center, Crossroads, 2041 Michigan Sturgeon Bay.
Monday, February 24
1:30 Lecture: What is a Freshwater Estuary
Many folks have requested information explaining what a freshwater estuary actually is. This PowerPoint presentation will answer some of those questions. Thanks to the generosity of our donors, it is open to the public and free. Meet at the Collins Learning Center, Crossroads, 2041 Michigan, Sturgeon Bay.
Tuesday, February 25
3:30 Environmental Exploration: "In Search of Green"
Geared for elementary students but open to learners of all ages, this is a hike to search for places where photosynthesis is still occurring. Dress for the weather. Free and open to the public. Meet in the Learning Center, Crossroads, 2041 Michigan. Sturgeon Bay
6:30 Master Gardener/Wild Ones Lecture: ”Native Shrubs for a Door County Landscape”
Jason Feldman of Jason Feldman Landscapes will recommend shrubs that help pollinators and birds thrive in the various soil types in Door County. Free and open to the public. Meet at the Collins Learning Center. Sponsored by Door County Master Gardeners (DCMGA)and Wild Ones – Door Peninsula Meet at the Collins Learning Center.
