7th Grade Science

Unit Title:  Energy

Objectives:

     1.  Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object. 

     2.  Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system. 

     3.  Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.

     4.  Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample. 

 

Plans:

Monday-Build solar cookers

Tuesday-Finish building solar cookers

Wednesday-Test solar cookers

Thursday-Review sheet for common assessment

Friday- Finish review sheet for common assessment

 

Monday-Review game

Tuesday-Common assessment on Energy

Wednesday-go over common assessment, practice questions in new KPREP format 

 

 


Review for Energy Common Assessment

 

1. Explain the difference between potential and kinetic energy.

            Potential is stored up energy.

            Kinetic is energy being used; it is in motion.

 

2. Define and give an example for each type of potential energy:

  1. Gravitational potential-energy something has because of its height.  It could fall.
  2. Elastic potential-energy something has because it is stretched or compressed.
  3. Chemical potential-fuel energy.  It can burn, blow up, or be used as fuel.

 

 

3. The amount of gravitational potential energy an object has depends on the object’s  _Weight_____ and ___Height________.

 

4. To increase the amount of gravitational potential energy an object has, either raise it ____ _Higher______________ or add ___Mass _________.

 

5. Illustrate a pendulum swinging back and forth. Label the point(s) where the pendulum has the most potential energy and the most kinetic energy.

 

 

Points 1 & 5 have the most potential. Point 3 has the most kinetic.

 

6. What happens to the amount of potential energy stored between objects with magnetic or static electricity as the distance between the objects decreases?

As the objects become closer, the energy stored increases.

 

7.  Tell the energy transfer that occurs when a person eats, then goes running.

            Chemical to mechanical and thermal

 

8. Tell the energy transfer that occurs in a hair dryer. 

            Electrical to thermal

 

 

9. State the law of conservation of energy.

            Energy cannot be created nor destroyed, only transformed.

 

10. Give an example of an energy transfer that follows the law of conservation, and explain how the law is being followed.

            Any energy transfer will work.  The law of conservation cannot be broken.

            A possible answer:  roller coasters potential energy transforms to kinetic (mechanical and thermal) as the roller coaster moves down the track.

 

11. In every energy transfer, some of the original energy transfers to ____ ___Thermal energy or Heat_____ due to __  Friction_.

 

12. Thermal energy always moves from ___Hot ________ to __Cold____

_______.

 

13. Illustrate and describe the speed of a solid, liquid, and gas.

 

Gas-particles move very quickly and spread out

Solid –particles are held tightly in place and only vibrate

Liquid-in-between, particles are moving slightly faster and spreading out some

 

14. How can something like ice move from being a solid, then liquid, then gas?

By adding thermal energy

 

15. How can something like steam move from being a gas, then liquid, then solid?

By removing thermal energy

 

16. Explain the thermal energy transfer that would occur between hot chocolate and marshmallows in a cup.

Heat would move from the hot chocolate to the cooler marshmallows by conduction

 

17. When does heat stop transferring between two objects?

When they are the same temperature

 

17. Is boiling soup an example of conduction, convection, or radiation?

Convection.  The hot soup rises, cools, and sinks.

 

19. You place a spoon in the boiling soup, and it gets hot. Is this conduction, convection, or radiation?  Conduction.  The soup is touching the spoon.  It is not convection because the spoon will not get hot and rise.

 

20. As your soup boils, you notice some droplets forming on the outside of the soup pan. What is happening?

The steam from the soup is hitting the outside of the pan, giving some heat to the pan, then turning back (condensing) to a liquid.

 

21. You mix two equal amounts of water that are different temperatures. How can you find the temperature of the mixture?

Take the average.   (Add them, divide by 2)

 

22. Define and give an example of a good conductor of heat.

Conductors-transfer thermal energy well.  Examples-copper, silver, gold, anything metal

 

23. You have 2 containers of water-one container has 50 mL and the other 100 mL.  Which will boil first? Why?

The smaller container-it has less particles to speed up.

 

24. Compare the boiling points of 50 mL of water and 100 mL of water.

They will both boil at the same temperature (100 degrees Celsius).  All water boils at the same temperature-regardless of amount.  It will just take a larger amount of water longer to reach this temperature.

 

25. Compare the thermal energy of 50 mL of boiling water and 100 mL of boiling water.

The 100 mL of water will have more thermal energy because it has more particles.  It can cause more change.