In Canada, the winter months bring fewer hours of daylight and colder weather. Due to the tilt of the Earth, which is about 23 degrees, the Sun’s light shines on the Northern Hemisphere less directly during these months. Some scientists hypothesize that the tilt of the Earth—along with the formation of the Moon—was caused by a big collision with a Mars-sized object early in Earth’s history.
This drop in temperature causes water outside to freeze—especially small bodies of fresh water. As the temperature drops, the movement of water molecules slows down until ice forms. A very small amount of water remains on the surface of the ice and constantly melts and refreezes. When you skate on ice, like on an indoor rink or a frozen pond, the friction from your blades helps melt this top layer—so you’re actually skating on a very thin layer of water!
Water also does something special when it freezes: It expands and gets less dense. Because ice is less dense than water, it floats on the surface. In lakes and ponds, this phenomenon allows fish and other wildlife to continue swimming beneath the ice over the winter.
Q: What is the record (in centimetres) for largest one-day snowfall in Canada?
A: 145 cm of snow fell at Tahtsa Lake, B.C., on Feb. 11, 1999.
Q: At what temperature is water most dense?
A: About 4°C—it actually gets less dense as it drops to 0°C.
Q: At what temperature does seawater freeze?
A: About -2°C. Rising temperatures associated with climate change have resulted in less Arctic sea ice.
Q: What is the shape of a snowflake?
A: Snowflakes are hexagonal.
Q: Where would you find a cold desert in Canada?
A: In the Arctic. Due to their low humidity and precipitation, some areas of the Arctic are known as “polar deserts.”
Q: What is graupel?
A: Small snow pellets, also known as soft hail.
Q: When is Earth closest to the Sun: winter or summer?
A: Winter. The Earth’s orbit around the Sun is elliptical (oval-shaped). Winter is colder than summer due to the tilt of the Earth, not Earth’s position around the Sun.
Q: What is the record for the coldest temperature ever recorded in Canada?
A: -63°C, a record set in Snag, Yukon, on February 3, 1947.