An engaging physical science lesson exploring gravitational potential energy, kinetic energy, and the law of conservation of energy through roller coaster engineering. Students analyze mechanical energy transitions at various track heights and evaluate how friction converts mechanical energy into thermal energy.
Acoustic Energy
The roaring sound and vibrations of the train transfer energy into the surrounding air molecules.
Total Conservation
No energy is destroyed! Total energy remains equal: \( E_{total} = PE + KE + E_{thermal} \).
⚠️ Engineering Consequence: Because of friction, every subsequent hill MUST be lower than the previous peak unless external energy is added.
Active Lab Mission
Engineer Your Energy Track
Track Design Criteria
Criterion 1: Start
Cart starts from rest at Summit Hill 1 (100% GPE budget).
Criterion 2: Loop
Cart must successfully clear a loop without rolling backward.
Criterion 3: Safety
Enter final brake zone safely with friction energy accounted for.
📝 Turn to Part 3 of your Energy Coaster Lab Worksheet to construct and justify your track profile.
Coaster Physics • Slide 6 of 7 Design Challenge
Synthesis & Debrief
Key Takeaways & Exit Reflection
Core Takeaways
Height determines potential energy (\( PE \)).
Speed is converted from potential energy (\( KE \)).
In an ideal system, \( PE + KE = \text{Constant} \).
Friction transforms mechanical energy to thermal energy.
Exit Question
"If a roller coaster cart has 40,000 J of Potential Energy at the summit, how much Kinetic Energy does it have at the valley floor (assuming 4,000 J lost to friction)?"
💡 Record your calculation on Question 4 of your worksheet!
Coaster Physics • Slide 7 of 7 Physical Science
Design & Justify
Design a thrilling yet safe track profile. Your track MUST include: (1) Initial Lift Hill, (2) One vertical loop, (3) One secondary hill, and (4) Final braking zone.
Summit (High PE) Loop Section Bunny Hill Brake Run (0 PE)
Sketch your coaster track curve above and label Heights at each peak.
5. Engineering Defense: Why MUST your loop’s maximum height be lower than your first hill?
6. Safety Consideration: How does the brake run safely stop the coaster at the end? Where does the remaining kinetic energy go?
Coaster Physics • Student Lab Worksheet Page 2 of 2
Maximum possible climb height = \( \frac{42,000}{50,000} \times 50\text{m} = 42\text{ m} \).
Part 3: Engineering Challenge Rubric & Defense (4 pts)
Exemplar Blueprint Criteria
Lift Hill #1 Highest Point
Must be tallest to supply entire energy budget.
Vertical Loop Height < Peak 1
Must retain sufficient KE at crest to avoid stalling.
Bunny Hill Height < Loop
Accounts for progressive friction energy loss.
Brake Run Ground Level
Smooth deceleration to 0 m/s via friction.
5. Model Defense for Loop Height:
"The loop crest must be significantly lower than Hill 1 because the coaster cart needs both potential energy (due to its height) AND kinetic energy (speed) at the very top of the loop. If the loop were as tall as Hill 1, all energy would turn into PE, leaving 0 KE—meaning the cart would stop dead and fall straight down instead of traveling through the loop curve."
6. Model Defense for Brake Run Energy Dissipation:
"Brakes use mechanical friction (or eddy current magnetic resistance) to do negative work on the train. The remaining kinetic energy is completely converted into thermal energy in the brake pads/fins and sound energy (screeching), bringing the velocity safely to 0 m/s without destroying any energy."
