9/14 Heat Transfer Mechanisms

Make your microwave popcorn.   (Yes, you will need to take turns)

• When  you pull the bag out of the microwave,   Check it for

• radiation transfer
• conduction transfer
• convection transfer

Write EVIDENCE you observe for each type of the transfer?  Record in your notes

• The teacher is making popcorn using an older, more traditional stove top method.  If you come near the pan, what EVIDENCE can you observe for the types of transfer?  Again, write in your notes.

Take a look at this slide show, which focuses on heat transfer methods.   How are these ideas similar or different to the ones you have already?

Popcorn from silviavuong

Heat transfer is all around us.   Use the simulation from 2D to explore this further.  For each problem, answer the question and tell me the name of the simulation.

1. Will a wind mill work better in the summer or the winter?  Explain, using the idea of convection.
2. Answer the questions on p. 30 of the pdf book.
3. Answer the questions on the Analysis of p. 35
4. Answer the questions on p. 41 about wall thickness.
5. Complete the model question on  p. 42

To find out how a microwave works, click the picture

Click to Run

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Part 2:   Heat Transfer and Weather

One last time....pictures

We're going to apply this idea of heat transfer to weather.

1.  Look at the pictures   What does re-radiation mean?   How does a cloudy night  change the temperature of the area?

9/13 UnderstandingEnergy using a Model

Today,we will be looking at the concept of convection, conduction, and radiation using an online book and simulation


Download the simulation



Read 25-27.  Be able to tell me the meaning of the following in your notebook.   Conduction, convection, radiation, kinetic energy, thermal energy, heat.   To do this WELL will take some time.

9/12 New Unit: Energy Transfer in Weather and on Earth

Today, we'll be looking at movement of fluids.  A fluid can be a liquid or a gas.

Activity 1:  Please do part 1 using water and food coloring.  There should be 2 groups per table.


Procedure

1. Tell the class that they will conduct several experiments to trace the currents when water is not evenly heated.
   
   
• In the first experiment, they will observe the movement of a drop of food coloring in still water.
  
  
• Then they will add a heat source and drop the food coloring in different places in the saucer.
  
  
2. Place three styrofoam cups upside down on a piece of paper.
   
   
3. Place the plastic plant saucer on top of the cups as shown. The cups should be near the outer edges of the saucer and evenly spaced.
   
   
   
   
4. Fill the plastic saucers three-quarters full with cool water. To make certain the water is still, let it sit before the experiment. Be careful not to bump the desk or table at any time during the experiment.
   
   
5. Using a dropper, slowly release a small amount of food coloring at the bottom of the saucer of water. Slowly remove the dropper, taking care not to stir the water.
   
   
6. Observe and record on the data sheet what the drop does as it sits in the tray. Ask students to draw what happens.

Variations
Repeat the experiment with the following variations. Ask students to record their observations after each variation. Make certain they start each trial with a clean saucer of water. Having several dump buckets placed around the classroom will be helpful.
For the following three trials, place a cup of hot water under the center of the saucer as shown. Fill the cup almost to the top.

Trial A: Place a drop of food coloring on the bottom of the saucer in the center, over the cup of hot water. Take care not to stir the water.

Trial B: Place a drop of food coloring on the bottom of the saucer about halfway between the center and the side. Take care not to stir the water.

Trial C: Place two drops of food coloring on the bottom of the saucer, one halfway between the center and side of the saucer, the other in the center. Take care not to stir the water.

Observations and Questions

1. For each trial, ask students to draw their observations from an overhead view, including an explanatory caption for each drawing. The drawings should show the movement of the colored water (currents) and its relationship to the hot water or heat source for convection.
   
   
2. Have students repeat the exercise, showing their observations from a side view.
   
   
3. What effect does the hot water in the center under the saucepan have upon the currents?
   
   
4. What type of heat transfer is taking place? How do you know?

Activity 2:  Please do the activity using dark material (dirt), light material (rock) and water.  


Procedure

1. Have students make data tables to record the time and temperature of the three experimental pie pans. Examples:
   
   

Heating Cycle
Surface material	Start time	Start temp.	Temperature each minute
			1	2	3	4	5	6	7	8	9	10




Cooling Cycle
Surface material	Start time	Start temp.	Temperature each minute
			1	2	3	4	5	6	7	8	9	10



2. Fill the pie pans to the same level, one with dark soil, one with light sand, and one with water.
   
   
3. Place the pie pans on a table or desk and position the lamp about 12 inches above them.
   
   
   
   
4. Place a thermometer into each pie pan, securing it so it measures the temperature just under the surface of the substance in the pan.
   
   
5. Record the starting temperatures on the data table.
   
6. Turn on the lamp and record the temperature of each substance every minute for ten minutes.
   
7. At the end of ten minutes, turn the lamp off.
   
8. Continue to record temperatures for each substance every minute for ten minutes.
   

Note: Feel free to vary the materials in the pie pans. Use different colored soils, dry and wet soils, grass, green or dry leaves, or different types of coverings such as plastic or aluminum foil. Encourage students to use their imaginations. You may wish to assign students to design and conduct their own research into the influence of surfaces on temperature.
Observations and Questions

1. Using the data tables, graph the heating and cooling cycles to compare the rates at which the various substances heated and cooled.
   
   
2. Which material absorbed more heat in the first ten minutes?
   
   
3. Which material lost the most heat in the last ten minutes?
   
   
4. Imagine that it's summer and that the sun is shining on the ocean and on a stretch of land. Which will heat up more during the day? Which will cool more slowly at night? Explain.
   
   
5. Imagine three cities in the desert, all at about the same altitude and latitude.
   
   
   • One city (A) is surrounded by a dark-colored rocky surface.
     
     
   • Another city (B) is surrounded by a light-colored sandy surface.
     
     
   • The third city (C) is built on the edge of a large man-made desert lake.
     
     
   • Which city would likely have the highest average summer air temperature and why?
     
     
6. The earth's surface tends to lose heat in winter. Which of the above cities would have the warmest average winter temperature? Why?
   
   
7. Since the sun is approximately 93 million miles from the earth and space has no temperature, how do we get heat from the sun?
   
   
8. How would the uneven energy absorption by different surfaces on earth (water, soil, snow, trees, sand, etc.) affect the atmosphere?

HOMEWORK:  Bring 2 packages of microwave popcorn for each table tomorrow.

9/11 Group Wind Mill Presentation

You have half of your day today to create a shared presentation for your group.

Open a shared Google presentation.  Share it with Mapowell and your group members.

Answer the following questions using your Stakeholder's input:

• Should we build an offshore windmill?  Give 3 or more pieces of evidence to support your position.
• How does a windmill work?  Explain, using words
• How much does a windmill cost?  Explain, and use your source.
• Think of 3 or more arguments that the opposite side would use and come up with counter-arguments.
• If windmills and solar power produce energy sources without creating excess carbon dioxide, is that a good thing or a bad thing?  Explain, and use one other energy type (oil, gas, wood, etc.) as a comparison.

9/6 Windmill blades

Build Your Best Blade

Decide on Your Group's #1 and # 2 blade combination.   You will test these using pp. 9-11 of your handout.

Also, try hooking up your motor to a buzzer or a light and see if you can get it to light.


FINAL COMPETITION

Using your two best blades, design a hybrid blade to be used in the competition.  This must be ready by 1 pm.


==============Friday's Quiz==============

Your quiz will be two sides of a sheet of paper and worth 30 points
The information on the quiz is found here

9/5 Cape Wind Extended

Part 1:  More information on your Case Study

• Town person (read pp. 15-16) who depends on tourism for a job
• Salesperson (read p. 10 on coal and p. 13 on wind)who stands to make a huge commission
• Environmentalist (skim pp. 9-12) who is worried about the safety of the fish, birds, and wildlife, as well as climate change 
• Electrical utility (read pp. 7-8) that wants to make sure there is power for the town but also wants to make a profit

When you get done, decide if you are pro or con on windmills.   Write down 5 arguments that support your position and put them here.  DO NOT write over another groups' data.

Part 2:  Test your windmill blades for the groups.

Create a table that lists

Name

Sketch of the Blade

#Blades

#turns in 10 sec

#voltage

Each person in your team must test two of their blade combinations.  Write this information down on a sheet of paper or on a whiteboard.

9/4 Wind Power Case Study

Step 1:

Today, we'll be looking at a case study.

The idea behind a case study is to look at things from multiple points of view and then apply that information to a new idea.

Our case study

You will be assigned one of 4 roles.

• Town person who depends on tourism for a job
• Salesperson who stands to make a huge commission
• Environmentalist who is worried about the safety of the fish, birds, and wildlife, as well as climate change 
• Electrical utility that wants to make sure there is power for the town but also wants to make a profit

Read the 3rd page of the case study.   Highlight 3 or 4 items that affect your group's point of view.

Do you think the turbine should be built?  Why or why not?

Present your viewpoint to the class in 1-2 minutes.

photo credit: axelivarsson via photo pin cc

Step 2

Now, we will look at an actual offshore Wind Farm, called Cape Wind.  Look at each of the resources below, and find out if the information shown supports your position or not.   Write down 3 or 4 highlights from each resource.

RESOURCE 1

RESOURCE 2

RESOURCE 3

Step 3: Reflection (online or on paper)

The goal here is to see that decisions are not always clear cut.  What you do will affect other living things.

Which other stakeholder group do you have the most in common with during this study?   Which do you have the least in common with in the study?

What are some strategies that you can use to get along with people who have different viewpoints?

Which stakeholder viewpoint convinces you the most?  Explain.