How Sleds Work

Introduction

For many of us, our first introduction to snow involved sledding. With a few inches of snow and a slightly-graded hill, we were running up and sledding down for hours at a time. Although the sled is a simple device, there are several factors that allow it to provide a fun means of sliding down a snow-covered hill. Here's a look at what makes sleds work.

Gravity by Way of Slope

The sled relies on two basic principles: gravity and reduced friction. The first is very simple: sleds work on a hill. Obviously, a flat surface wouldn't work for your average sled. In some cases, such as dogsleds, a different source of movement is used; however, the common sled relies on gravity. The steeper the hill, the faster the sled moves.

Glide

Reducing friction is allowed for by the slick, smooth surface of the snow that enables the sled to glide downhill. Clearly, sledding down a grass or rock hill, even if it is steep, would not work because there would be too much friction to allow for motion. Sleds also use surfaces that are good for gliding. The most basic sleds such as discs or flat plastic models rely on a flat, smooth surface. Flexible Flyer style sleds use long metal rails to carve down snowy slopes. Other sleds use small skis.

Steering and Braking

Sleds vary by model regarding further functions like braking and steering. The most basic discs don't have any steering or brakes and simply rely on your feet, hands, body and leveling of the hill to control and stop. When in doubt, you can always roll off the sled and onto the snowbed. More advanced models of sleds have steering mechanisms like rope, rotating front end mechanisms or even steering wheels. Brakes are generally in the form of a lever that the rider pulls up causing it to dig and drag in the snow, and slowing the speed to a stop. Some sleds also include handles or rope for carrying or pulling the sled back up the hill.