Chapter 7.1
DESCRIBING MOTION
When is an object in motion?
I. An object is in motion if its position changes relative to another
object.
A. REFERENCE POINTS: A reference point is a place or
object used for comparison to determine if something is in
motion.
1. An object is in motion if it changes position relative to a
reference point.
2. The school bus incident.
B. RELATIVE MOTION: Using your chair as a reference point,
using the Earth, using the Sun, using the Milky Way…
1. Carousel photo:
2. Are the people moving relative to each other? Are they
moving relative to the tea cup they are sitting in? Are they
moving relative to objects on the ground?
C. MEASURING DISTANCE: Scientists use a system of
measurement called the International System of Units.
1. Distance is the length of a path between two points.
2. The prefix milli- means “one thousandth” so there are
1000 mm in a meter: 1000 millimeters (mm) = 1 meter (m)
3.
The prefix centi- means “one hundredth” so there are
100 cm in a meter: 100 centimeters (cm) = 1 meter (m)
4. The prefix kilo- means “one thousand” so there are 1000
meters in a km: 1000 meters (m) = 1 kilometer (km)
7.1 Exit Ticket
1. Fill in the common conversions for length:
1 meter (m) = _______________________millimeters (mm)
1m =
________________centimeters (cm)
1 kilometer (km) = ______________m
2.
What is the distance between these two points? _________________cm
*
*
3. Why is it important to know if your reference point is moving?
____________________________________________________________
____________________________________________________________
____________________________________________________________
7.1 Exit Ticket
1. Fill in the common conversions for length:
1 meter (m) = _______________________millimeters (mm)
1m =
________________centimeters (cm)
1 kilometer (km) = ______________m
2. What is the distance between these two points? _______________cm
*
*
3. Why is it important to know if your reference point is moving?
____________________________________________________________
____________________________________________________________
____________________________________________________________