📏 Measurement - Length
Length is the measurement of an object from one end to the other, while height tracks vert
▶ Play Door 18Measurement - Length
Length tells us how long an object is from one end to the very other end. It can also tell us how tall someone is (height) or how far apart two places are (distance). In Grade 2, we learn how to make smart estimates, use descriptive comparing words, and transition from counting with our bodies to measuring precisely with scientific metric tools.
• Estimating Lengths Using Standard Visual Benchmarks: An estimate is a smart guess. To make a great estimate, you can look at real-world objects as benchmarks:
• 1 Centimetre (cm): About the width of your little finger or the width of a standard staple.
• 1 Metre (m): About the distance from the floor to a doorknob, or one giant step taken by an adult.
• Comparing Lengths Using Relational Adjectives: When we look at two or more objects, we use specific comparative language to describe their lengths:
• Long, Longer, Longest:…
Worked example
Problem: A surveyor needs to catalog the sizes of different classroom items. Choose the best standard metric unit (cm or m) to measure: (a) The length of a plastic sharpener, and (b) The height of the classroom door.
- Analyze item (a): A plastic sharpener is a small handheld object. Its size is tiny, close to our visual finger benchmark. Therefore, the centimetre (cm) is the ideal unit.
- Analyze item (b): A classroom door is large, tall, and much higher than an adult's height. Measuring it in tiny finger widths would take too long. Therefore, the metre (m) is the ideal unit.
Answer: (a) Centimetres (cm), (b) Metres (m)