Friday, 16 August 2013

Class Scribe, Drums, fireflies, skateboard ramp and potato chips... Oh My!

Guest post by Mrs. Tolisano




Class started with housekeeping items, homework and a review of the last class, including nuclear bombs. What are kinetic energies involved? Are their chemical reactions involved?









Mr. Prophet showed several videos to demonstrate the change in energy:


Wind turbine
starting energy (where is it coming from?) --> Final energy
wind (kinetic) things we can see and feel easily --> kinetic of turbine --> electricity and some sound.

Powerlines
electrical potential --> electricity kinetic --> light, thermal & sound

Fireflies
A chemical reaction in the animal changed chemical --> light (bioluminescent) & probably thermal.

Firecrackers 
Chemical --> sound, light and thermal

Drums
Hitting a drum starts out with a kinetic energy of drum stick to kinetic of drumstick -->  elastic and kinetic of drum --> sound
(video effect of a drumset in slow motion)

Space Jump
gravitational energy --> kinetic energy

 


Next step on the agenda was the SkateBoard Simulation. 

What did we learn?
  • What happens to the total energy over time?
    energy remains the same - it remains constant
  • What happens to the potential and kinetic energy?
    The kinetic is highest, increased to a maximum and the potential is almost 0
  • What happens to the potential at the top of the ramp?
    Potential is high, kinetic changes into gravitational
  • What is the relationship between kinetic, potential and total energy of the skateboard system?
    Total energy= kinetic + potential
What if we add Track friction?
Kinetic energy becomes 0
What happens to the potential energy over time?
It decreases, almost to 0
What happens to the thermal energy over time?
It increases each time until it becomes the same as the total energy
What happens to the total energy over time?
It stays constant
What is the relationship between all of them?
Total= Potential + Thermal + Kinetic

Moving on to the Investigation...

ALWAYS BE SAFE!
  • Tie back long hair
  • Do not sit
  • Wear googles throughout the whole investigation
 Observation

Step 1: Weigh the potato chip


 Step 2: Measure 10 ml of water for the test tube


Step 3: Light a match and the alcohol
 


Step 4: Burn the chip with the fire


Step5: Thermometer goes in the water. Record temperature of water (initial)

Step 6: Hold burning chip under test tube with thermometer in it


Step7: Measure and record the temperature of the water after the entire chip burned.

Summary of Main Ideas:
  • Energy changes are all around us!
  • Anytime there is a change, we can analyze it in terms of energy.
  • In the investigation, when the chip/biscuit were burned, the chemical energy --> thermal of air --> thermal of test tube and water.  This changed the temperature of the water.




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