Physical Science, Module 8, Weather and Its Prediction

Click for Videos we Watched for Module 8 
Play  Quizlet.  Just scroll down and click on Physical, then scroll to find the Module you want.

This Module had one new experiment, and the continued Weather Experiment from Module 7.
We didn't do the new experiment, 8.1, Create Your Own Lightning.  I just let them try it on their own at home.  It was to use a balloon to create a spark, just the way lightning is created, and hear a snap just like thunder is made.  In a totally dark room, rub the balloon over your hair, then slowly move it toward your fist, knuckles up.  As the balloon nears your hand, you will feel a small charge, then hear a snap.  You may even see a spark!  You can learn more about how lightning is made by watching the videos I linked to above.
We did two other experiments instead. 
The barometer experiment is probably in the Second Edition since Michelle had it on her blog.  Correction: She got this experiment from another source.  Here's how the teens made their barometer.  I decided to make ours similar to her other one. Then I looked awhile on YouTube to find out all the little tips from different people.  I didn't find anything that explained everything in one video, so I ended up not posting a video about it on Homeschooler's Resources.
To make our barometer, we used:

• a pint jar 
• a 12" balloon with the end cut off
• several rubber bands to keep any new air from getting into the jar
• super glue to attach the straw to the middle of the balloon (I didn't have rubber cement that one video recommended)
• a (straight, not bendy) straw cut diagonally at one end
• and tape to make sure the straw stayed on

A barometer measures the atmospheric pressure.  Air is pressing on us from all around!  If the pressure is higher than when we made the barometer, the air will press down slightly more on the balloon, making the straw rise.  If the pressure is lower, meaning the pressure outside the jar is lower than the pressure inside the jar, the balloon will bulge up slightly, making the straw tip go down.  High pressure indicates clearer weather, and low pressure occurs when there are clouds.
I saw the chart on the wall at Michelle's blog, and made one similar.  Ahem!  I got carried away, and just kept adding to it.  ►Printable Chart
I made the chart so that a pint jar would hit about mid-way between the sun and cloud, but you can certainly tape it on the wall higher, or sit the jar on a small book to get it in the right position.
If it is a rainy or cloudy day when you make it, you can position your chart so that the straw tip hits slightly below the top edge of the cloud, and if sunny and clear, nearer to the sun.  Twice a day, we will be noting where the straw tip touches the chart and marking it, noting the time of day.

This will also help the kids to understand their ongoing Weather Experiment.  I will be checking Wunderground to see if I can catch when the barometric pressure is 29.92 inches, which is average.  I'll call the kids to let them know and they can mark with a pencil the points that the straw touches on each end of the chart, then with a ruler draw a light pencil mark across the chart.



The other experiment we did was to measure the dew point.  In looking up videos to go along with the text, I came across one that explained this, and decided to do it with the kids.

To measure the dew point, we used:

• a short wide glass
• a bulb thermometer
• close-to-room-temperature water
• ice cubes

They put the thermometers in the glasses and noted the temperature.  They added a few ice cubes and gently stirred the water with the thermometers.  As the ice cubes melted, they added more, one at a time.  When they saw the cloudy film of condensation begin to form, they checked the temperature on the thermometers.  This was the dew point.  I did this experiment last night, and it was 44°.  Today it was 40°.  This is the temperature at which point vapor condenses on objects.  It cannot condense in mid-air without having something to condense on.  A cloud cannot form without condensation nuclei - very fine particles in the air.  You have probably seen these when the sun shines through a window.  When clouds form, you know that the temperature inside the clouds and the dew point are equal.
The higher the pressure and humidity, the higher the dew point.

I gave an overview of the chapter, and we talked about hurricanes and how lightning forms.  They really laughed and got a kick out of the 1-minute video Science Explains Lightning. We watched it 3 times. =)  They drew and labeled the graph that was at 3:40 on the last video we watched, Hurricane Hunters.
Click for Videos we Watched for Module 8