G. Enid's Home Page 1.

G. Enid Walker's Home Page Welcome Everyday is an adventure in paradise, You may dream any dream that you want to join me now for one of mine.

Here is a Lesson 1 Experience:

Our universe is expanding. Here is a way to visually explain this to your students.

Equipment: Balloon, felt tip marker, string, and a metric ruler.

Procedure: Partially inflate a balloon. Fold the neck and clip it shut with a clothespin so air doesn't escape. Draw six (6) evenly spaced dots on the balloon with the marker. Label the dots A through F. Use a string and ruler to measure the distance in millimeters, from dot A to each of the other dots. Remove the clothespin and inflate the balloon once more. Measure the distance of each dot from A again. Inflate the balloon once more and take new measurements. (Becareful not to pop the balloon.)

Questions to ask your students:
1 Which distances changed the most? The least?
2 If each dot represents a galaxy, describe the motion of the galaxies relative to one another.
3 Is the universe expanding?

Experience #2 Where on Earth's surface is the magnetic field the strongest? The answer: Because all magnetic force lines merge at the Earth's poles, the magnetic field is strongest at these two locations.

Demonstration: Make a sketch of Earth on an overhead transparency. Label the geographic poles. Place the transparency over a bar magnet on an overhead projector. Rotate the figure so that the magnet makes an 11.5 degree angle with the rotational axis of Earth. Sprinkle iron shavings over the transparency and tap it lightly. Have a student volunteer explain the relationship between this demonstration and Earth's magnetic field. (Be sure to tape a border around the transparency so iron filings do not get into the projector.)

Supporting Notes: Convection currents deep inside Earth's mantle power the movement of the tectonic plates. Scientist hypothesize that movement of material inside Earth also generates a magnetic field. The magnetic field of Earth is much like that of a bar magnet. Earth has a north and south magnetic pole just as a bar magnet has opposite magnetic poles at its ends. The shavings align with the magnetic field of the magnet. Earth's magnetic field is similar, almost as if the earth had a giant bar magnet in its core.