thinking critically

16. much discussion has focused on the need to drive more efficent cars and use less electricity.if the law of conservation of energy is true. why are people concerned about energy usage?
the problem is that the original form of the energy (gasoline) is  now mechanical energy and is of no use once wasteful.
to make it usable again it need to be gasoline which takes an extremely long process in nature.

17. if heat flows in only one direction, how can both hot and cold liquids reach room temperature as they sit on a table?
the heat from the hot object goes in the air and the air goes to the cold liquid

18. think about what happens to jack and jill in the nursery room. what kinds of enrgy are used? how was each energy form used?
if they are walking they are using kinetic energy but if they are sit down they are using potential energy

19. compare the 3 temperature scales you learned about. how are they different? how are they similar?
the celsius scale is based on 0°.
many physical and scientific formulas can be expressed on the kelvin scale
farenheit scale, water freezes at 32° and it boils at 212 °
similar: they are all based off the freezing and boiling points of water.
different: they define them at different numbers.

20. use what you know about the movement of thermal energy to explain why you would place a minor burn on your arm under cool, running water.
because heat is transfer from the warmer object to the cooler object.

DEVELOPING SKILLS

now when you are standing up on the tramp you have potential energy due to standing at a higher level  above ground.
when you are jumping on thr tramp you have both kinetic and potential energy. potential for the springs (as energy that is stored) and height.kinetic energy whwn you are moving in the air up and down.
so when you are in your highest point in the jump you have the most potential energy.
when in the middle half you have the most kinetic energy.
when you are back in the bottom, touching the mat you again have max potential energy due to the spings.