A typical bathtub holds about 50 gallons of water. A professional-sized ice rink requires a lot of water. It takes about
STEM News: Game On!
1
THE CHEMISTRY OF HOCKEY uring one hockey game, players skate nearly 200 miles. As they skate back and forth across the rink, the blades of their skates slice, shred and shave the surface of the ice. But thanks to ice technicians who use engineering and chemistry skills, the ice at a professional hockey rink stays smooth.
BATH MATH
A typical bathtub holds about 50 gallons of water. A professional-sized ice rink requires a lot of water. It takes about 10,600 gallons to cover the surface 1 inch thick. Do the math and calculate how many bathtubs that would fill. 50 I0,600
A HOCKEY RINK IS BUILT IN LAYERS OF ICE
WHY NOT FREEZE THE ICE IN ONE BIG FLAT ICE CUBE? BECAUSE BUILDING IT UP IN THIN LAYERS CREATES A STRONGER SURFACE THAT WON’T CRACK.
10 clear sealing layers added together make the ice 1” thick lines and logos are painted on this layer’s surface 1/16” clear layer
Hockey gear has come a long way through the years. (This player must be wearing his “casual Friday” uniform.)
1/32” white painted layer 1/32” clear base layer
Have you seen ice cubes that look cloudy white? That’s oxygen trapped inside. Too much oxygen softens ice (think of a snowcone), making the blades of skates sink into the ice and go slower.
Snowcones make terrible hockey rinks but pine cones are even worse.
Water contains tiny traces of dust and minerals. Too much of this can soften ice. Too little can make it too hard. Chemistry studies helped ice rink professionals find just the right amount of minerals for a perfect ice surface.
STEM News: Game On!
2
MAKING RINK ICE
Making the ice for an official NHL hockey rink takes science and about four days.
Purified water is sprayed onto a concrete slab that rests on top of pipes filled with chilled salt water. Salt water freezes at a lower temperature than fresh water. This lowers the slab’s temperature to 16° Fahrenheit, cold enough to flash freeze the thin layer of fresh water. =0 =2 =5 =8 =1 =3 =6 =9 Fresh water freezes at _____° F (0° C)
Salt water freezes at about minus _____° F (minus _____ ° C)
An NHL hockey rink is _______ feet long and ______ feet wide.
The Story of the Hockey Puck WHACK! A hockey puck slammed into this article, scattering some of the words. Can you replace them all?
Hockey pucks weren’t always made of black __________ like they are today.
Early pucks were balls, stones, lumps of coal, or _________ cow or horse poop. Later, wooden pucks were used for many years. Mothers sometimes put hot baked ___________ into their children’s skates so that the skates would be cozy and
warm when the kids reached the rink or ________. The potatoes were not thrown away. They eventually froze and were used as pucks! Although rubber was _______________ in 1839, it wasn’t until the late 1880s that someone thought of making rubber pucks.
A hockey player’s ice skate blades are made of steel. But the edge is not shaped like a knife blade. The blade has a little groove down the center of it, giving it two sharp edges. This double-edge blade gives skaters the ability to dig into the ice, making it possible to stop, start, or change direction more quickly.
blade blade edges
STEM News: Game On!
3
TECHNOLOGY ON THE ICE eeping the ice smooth in a hockey rink is a really big job. And it requires some really big technology.
HOW A ZAMBONI ICE RESURFACING MACHINE WORKS
The Zamboni ice resurfacing machine was invented by Frank Zamboni in the 1940s. When indoor ice rinks were first built, the ice was smoothed by pulling a scraper behind a tractor, shaving the surface. Three or four workers would scoop away the shavings and spray the surface with water. This would take more than an hour! UNEVEN ICE Frank Zamboni saw this as an engineering puzzle to be solved: how could he make a IS A REAL good sheet of ice in a short period of time? PAIN! By using science experimentation, observation and engineering, Zamboni invented a machine that makes the task of ice resurfacing fast and efficient. A scientist uses observation skills. How good are your observation skills? Look carefully to see how many snowflakes you are able to find below. Have a friend try. Did you find the same amount?
Shaving A blade
shaves a thin layer from the surface of the ice.
Collecting
After a horizontal screw (called an auger) gathers the shavings, a vertical auger lifts and propels them into the snow tank .
Washing
Water is fed from a wash-water tank to the “conditioner” , which rinses the ice. Dirty water collected in front of a squeegee is vacuumed, filtered, and returned to the tank.
Resurfacing
Clean water from the ice making tank is delivered to the ice through a pipe and spread evenly by a towel pulled across the ice behind the conditioner .
STEM News: Game On!
4
SCIENTIST’S NOTEBOOK
The Reaction Time Test MATERIALS:
WHAT DO YOU CALL A HOCKEY PLAYER WITH SLOW REACTION TIME? TOOTHLESS!
• yardstick • friend
Rest your arm on the edge of a table or chair, with your hand hanging over the edge. Hold your thumb and index finger about one inch apart.
HOW FAST CAN YOU REACT? Goalies need to have the ability to react extraordinarily fast when a hockey puck is whizzing towards them at 90 miles per hour.
Have a friend hold the yardstick so that its bottom end is between your two fingers.
Without warning, have your friend drop the yardstick. Close your fingers to catch the yardstick as quickly as you can.
Ready for the science scoop?
The average person catches the yardstick at around 6 to 8 inches. This is a reaction time of .177 to .204 seconds. That’s pretty fast, right? But to match the reaction time of a
professional hockey goalie, who needs to stop a puck traveling at 90 mph from 20 feet away, you would have to catch the yardstick at 4.5 inches! A hockey puck traveling at 152 feet
1. Salt water freezes at a higher temperature than fresh water. 2. Oxygen inside of ice makes it more clear.
Write down the number of inches the yardstick fell before you caught it. Try it 10 times and calculate your average.
3. In one hockey game, a player can skate nearly 200 miles.
1.
inches
2.
inches
4. Some early hockey puck s were stones, lumps of goal or frozen cow poop.
3.
inches
4.
inches
5.
inches
6.
inches
7.
inches
8.
inches
9.
inches
10.
inches MY AVERAGE:
per second will travel 20 feet in .152 seconds. That’s about 1/10th of a second. Better keep practicing with that yardstick if you want to be a goalie!
5. A small amount of minerals in the ice of a hockey rink helps the ice from being too hard. 6. A typical bathtub holds 100 gallons of water.
Biofeedback
Explore your reaction time using the science of biofeedback in the Chevron STEM Zone!
