Did you know that gasoline packs a powerful punch with about 56 megajoules of chemical energy per liter? That’s more energy than the same amount of TNT and enough to keep a toaster running for an entire day! Cars use this energy by burning gasoline to transform it into kinetic energy, which is what makes them move. However, it’s important to note that nearly 80% of this energy is lost as heat in the engine. Still, the remaining 20% is quite significant.
To give you an idea of how gasoline powers a car, it takes about five teaspoons of gas to accelerate a two-ton car to 60 kilometers per hour (kph). To maintain that speed, you’ll need about a third of a cup more for every additional minute. While this might not seem like a lot, the energy of a car moving at 60 kph is comparable to dropping an elephant—or even a stegosaurus—from the top of a three-story building!
When a car needs to stop, all that energy has to be absorbed somewhere. If you use the brakes, they dissipate the energy by heating up. In the event of a collision, the energy is absorbed by the bending and crumpling of the car’s outer metal areas. Cars are designed to crumple in a way that extends the duration of the impact, reducing the intensity of the acceleration needed to stop. This is crucial because rapid acceleration over a short time isn’t good for our soft human brains and organs.
Most cars have about 50 centimeters of crushable space to dissipate the energy equivalent to our falling stegosaurus. During a crash, this space needs to maintain a resistive force comparable to a quarter of the thrust of a space shuttle’s main engine. Over half of this controlled crumpling is managed by steel rails connecting the front bumper to the car’s body, which bend and deform to absorb energy and slow the car down. The rest of the energy is absorbed by other structural metal pieces throughout the car’s front.
This carefully engineered destruction allows a crashing car to decelerate at a high but reasonable rate, similar to what fighter pilots or astronauts experience in centrifuge training. If cars were as rigid as they were before the 1950s, they would stop so quickly that the acceleration would be 15 times what fighter pilots experience in training. Thankfully, engineers have developed cars with crumple zones surrounding a rigid safety cell, making them safer for everyone.
This video was made possible by Ford, where I had the chance to speak with a crash test safety engineer. They explained the complex physics and engineering involved in vehicle development and crash performance. Ford emphasizes the importance of using original parts developed and tested for their vehicles. If you’re interested in learning more about why the right parts matter, you can visit takeagoodlook.com.
In conclusion, making this video reinforced the idea that big dents and deformations in a car’s body aren’t just aesthetic issues—they can be safety hazards too. So, it’s crucial to understand the energy dynamics of gasoline and the importance of car design in keeping us safe on the road.
Calculate the energy required to accelerate a car from 0 to 60 kph using the given information. Use the energy content of gasoline and the car’s weight to determine how much gasoline is needed. This will help you understand the conversion of chemical energy to kinetic energy.
Create a model of a car’s crumple zone using materials like cardboard and rubber bands. Test its effectiveness by simulating a crash with a small weight. Observe how the crumple zone absorbs energy and discuss the importance of this feature in car safety.
Participate in a debate on the most important innovations in car safety. Research different safety features, such as airbags, seatbelts, and crumple zones, and argue which has had the greatest impact on reducing injuries and fatalities in car accidents.
Watch a crash test video and analyze the role of crumple zones and other safety features. Discuss how these features work together to protect passengers during a collision. Reflect on the engineering principles that make these features effective.
Invite a local automotive engineer or safety expert to speak about the latest advancements in car safety technology. Prepare questions in advance to learn more about the challenges and innovations in designing safer vehicles.
Energy – The capacity to do work or produce change, often measured in joules in physics. – The energy required to lift the car to the top of the hill was calculated using the formula for gravitational potential energy.
Gasoline – A liquid fuel derived from petroleum, used primarily in internal combustion engines. – The efficiency of the engine was tested by measuring how much gasoline it consumed over a set distance.
Kinetic – Relating to or resulting from motion, often used to describe energy associated with moving objects. – The kinetic energy of the moving vehicle was converted into heat energy by the brakes.
Acceleration – The rate of change of velocity of an object, often measured in meters per second squared. – The car’s acceleration increased as the driver pressed harder on the gas pedal.
Brakes – A mechanical device that inhibits motion by absorbing energy from a moving system. – The effectiveness of the brakes was crucial in preventing the car from skidding on the wet road.
Crumple – To deform or collapse under pressure, often used to describe the behavior of materials in a collision. – The car’s crumple zones absorbed much of the impact energy during the crash, protecting the passengers.
Design – The process of planning and creating something with a specific function or intention, often involving technical specifications. – The design of the new bridge incorporated advanced materials to withstand high winds and heavy traffic.
Safety – The condition of being protected from or unlikely to cause danger, risk, or injury. – Engineers prioritized safety by including multiple fail-safes in the nuclear reactor’s design.
Collision – An event where two or more bodies exert forces on each other for a relatively short time, often resulting in a change of motion. – The collision between the two vehicles was analyzed to determine the forces involved and the resulting damage.
Engineering – The application of scientific and mathematical principles to design and build structures, machines, and systems. – The engineering team worked tirelessly to develop a more efficient solar panel system.
