Sara E. Thomas
Next we will compare the canoe to the sailboat. The design of the hull and the current of the water still have an effect on the sailboat, however the biggest difference is its power source: wind. Using sails to employ the force of the wind to propel the boat forward, there is far less reliance on human muscle power on these boats. If the wind is coming from behind the boat then it gets caught in the sails which push against the air similar to the way the paddles pushed against the water, propelling the boat forwards. However, if the wind is coming from another direction then Bernoulli’s principle comes into play. Each sail is curved in such a way that when air molecules meet the sail they split and part of the air travels around one side of the sail, while part travels around the other side. What makes the sail work is that one side of the sail is curved, creating a longer distance for air to travel over. The air which travels over the longer distance does so in the same amount of time it takes the air to travel over the shorter distance, meaning that the air molecules are more spread out on the longer side. Because of this the more dense air tries to move towards the area where the less dense air is, pushing the boat forwards. (Fig. 3) Airplane wings work on the same principle. (Anderson, Newton’s Laws and Lift) Because the boat relies more on wind power and less on human strength it can often travel much faster than a canoe, however if there is no wind at all it may be very difficult to get where you are going.