Discovering Pi activity - have the students measure the circumference and diameter of several circular objects and divide the circumference by the diameter.
Use a surveyors wheel to demonstrate a real life application of unitizing circumference measurement. You can make a surveyors wheel with an old unicycle or other creative means and have the students calculate the length of the school yard.
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Calculating the circumference of a circle activity. Give students a piece of string and a circular object. Have the students measure the diameter and cut the string. Have them measure the circumference and cut the string. Have them compare the two pieces of string. The circumference is a little more than 3 times the length of the diameter. Visual proof that the diameter times pi equals the circumference.
Do something fun to celebrate "pi day"
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Have the students draw a circle on a coordinate plane with the center on the origin. Have the students estimate the area of the circle by counting all the square units that are at least 1/2 enclosed by the circle. Then have the students make a square with one corner at the origin (center of the circle), the base is the radius of the circle and the height is the radius of the circle. Calculate the area of the square then multiply the area by 3. The number should be close to the area estimate made earlier. Visual proof that the area of a circle is equal to the area of a square with sides of length r multiplied by pi.
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Finding the center of a circle |
Have students make their own set of fraction circles
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This slide show demonstrates several different ways to find the center of a circle. After viewing the slide show have the students find the center of a circle using several different methods.
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fraction circles - need: cardstock circles, ruler or straight edge, protractor
Have the students make their own set of fraction circle manipulatives using colored cardstock. Use colors that match the magnetic set of fractions circles. I bought a 3 1/2" circle punch. You can make 9 circles out of a 12X12 inch sheet of cardstock, but only 4 out of a 8 1/2 X 11" sheet of cardstock. 1, 1/2, 1/4, 1/8 - Wholes, halves, fourths, and eights are really easy. Students just fold the circles in half and cut. For other fractions it was a bit trickier. First the student has to find and mark the center of the circle. You can do this by taking the 1/2 circle piece and tracing along the center edge then moving and doing it again. The place where the two lines meet is the center. 1/3, 1/6, 1/12 - Once you find the center you need one radius. Mark from the center to the edge of the circle. From there you use a protractor to measure 120 degrees to find thirds. To find 1/6 you can do this and then cut each piece in half. We talked about how there is more than one way to do things. Same for 1/12. 1/5, 1/10 - Once you find the center you need one radius. Mark from the center to the edge of the circle. From there you use a protractor to measure 72 degrees to find fifths. To find 1/10 you can do this and then cut each piece in half. We talked about how there is more than one way to do things. |