The Physics of a Slap Shot
When it comes to impressing the fans, nothing beats a slap shot. Let’s take a closer look at one of the game’s most fantastic features and explore all the science that lies behind it.
This is the second article of three published alongside our new feature exhibition Hockey: Faster Than Ever.
1. The Potential Energy Stage
The player gets ready… up goes the hockey stick and down it comes towards the ice. This sweeping energetic movement fills the stick with what’s known as potential energy. Potential energy is the amount of energy an object can store based on its shape and position. Imagine a coil spring. The potential energy is stored in its compressed shape. When the spring is decompressed, that’s when it releases all its stored energy. On the ice, the hockey stick’s potential energy is released and transferred when it hits the puck. In fact, you can only really see potential energy once it is released and converted into another form of energy. Read on to learn more!
2. The Energy Transfer Stage
The player’s fast sweeping movement brings the hockey stick down towards the surface of the ice. The stick’s palette hits the ice a fraction of a second before it hits the puck and this is when the weight of the player has a chance to transfer to the stick. All the potential energy from the player’s weight actually bends the stick. Even if the stick loses some of its speed when it hits the ice, there is not, as you might suspect, a loss of energy. If it loses any of the speed energy it gained from the sweeping movement of the player, the fact that the stick comes in contact with the ice simply means that the energy from the player’s weight can be added or transferred to it before it hits the puck. This brief moment on the ice is ultimately a powerhouse!
3. The Kinetic Energy Stage
Finally, the energy-filled stick comes into contact with the puck. Players flick their wrists and shift their body weight to fully unleash all that stored potential energy and drive it into the puck. Once the energy is transferred to the puck, the energy becomes kinetic, that is, energy that moves. And that’s when the puck really flies!
If you want to calculate the kinetic energy of a moving object, you need to know its mass (its weight) and its velocity (its speed). If a puck were twice as heavy, it would have twice the amount of kinetic energy it usually has. If that same puck also moved twice as fast, it would have four times the amount of kinetic energy. Energy adds up! But since regulation hockey pucks always weigh the same, a fiery slap shot is ultimately about the kinetic energy players can give it by using their skills to increase its speed.
4. He shoots….
No matter how fast a puck can fly, it needs to be accurate if it’s going to help win the game. Once all that energy is transferred to the puck, the stick and the player have one last chance to help determine exactly where it will go using a combination of the curve of the stick and the player’s shift in weight. After that, the puck is in flight. Meanwhile everyone holds their breath to see if it makes its target.
He scores!!! Wow, all that science and physics really happens fast! Good thing we have instant replays!
Want to test your slap shot skills? Come visit the hockey lab at the Hockey: Faster Than Ever exhibition at the Montréal Science Centre. Find out what science can teach you about your slap shot!
To learn more about all the science behind our favourite national sport, don’t miss the Hockey: Faster Than Ever exhibition at the Montréal Science Centre from now until September 10, 2023.
Sources:
The Slap Shot in Ice Hockey
https://aapt.scitation.org/doi/full/10.1119/1.5018677
4 Stages of the Slap shot
https://www.crossicehockey.com/wp-content/uploads/2020/10/Slapshot-chart.jpg
Britannica – Potential Energy
https://www.britannica.com/science/potential-energy
Britannica – Kinetic Energy
https://www.britannica.com/science/kinetic-energy
