Why is the Hudson called "The River that Flows Both Ways"?
Because the saltwater from the Atlantic Ocean has tides that, when the tide rises, pushes the water up the river, while the freshwater (originating from a lake on New York State's highest peak in the Adirondack Mountains) always flows towards the Atlantic Ocean.
Your printed Activity Guide shows some mixed-up boats and houses from Hopper's paintings. Scroll down to see the full pictures:
This painting by Edward Hopper is called "Ground Swell." (This painting can be seen at the National Gallery of Art in Washington D.C.) While the painting might look bright and cheery, there are elements in it that may hint at impending danger. (See the link to the National Gallery's description of this painting for more details.) Edward painted this in 1939, when he was 57 years old, right as World War II broke out in Europe.
This painting is called "The Long Leg" and it depicts a sailboat near the Long Point Light at Provincetown, Massachusetts. Hopper painted this when he was 53 years old. (You may see this painting in real life at The Huntington Library, Art Museum, and Botanical Gardens in San Marino, California.)
Edward Hopper painted "The Bootleggers" when he was 43 years old (in 1925). During this time Edward made this painting, sales of alcohol were prohibited in the United States ("Prohibition" lasted for 13 years: 1920 - 1933). A "bootlegger" was a person who made, sold, or distributed illegal things.
This painting by Edward Hopper is called "Captain Upton's House" and it depicts a lightkeeper's house at Two Lights in Cape Elizabeth, Maine. Hopper painted it when he was 45 years old. (This painting is owned by the famous comedian Steve Martin. Steve is a REALLY BIG FAN of Edward Hopper.)
A LITTLE MORE ABOUT HOPPER:
Hopper said once in an interview (Arlene Jacobowitz, Brooklyn Museum, 1966), “I thought at one time I’d like to be a naval architect because I am interested in boats, but I got to be a painter instead.”
Hopper grew into a mature artist who painted not only on the shores of the Hudson in Nyack, but also on the banks of the Seine in Paris, and on the sandy ocean beaches of Maine and Massachusetts.