Here is a simple idea for students to practice accurate measurement and position with a reference point: Front of the room is positive motion and back of the room is negative motion Materials: Meter stick, cup, masking tape, coffee can, book, bell, rock Procedure: Have students create a table with object versus position in centimeters. A piece of masking tape will be their reference point. Students will work with partner to complete the table by making accurate measurements which will include the correct sign. Object Distance (cm) Cup 70 Book -200 Coffee can -150 Bell -75 Rock 125