Estimating the weight of a giant pumpkin

Activity

Learn how to estimate the weight of giant pumpkins. Have you grown a monster?

• Estimated time: minutes
• Location: Outdoors & Indoors
• School term: Early Autumn, Late Autumn
• Level of experience: No experience needed
• Subject(s): Maths, Science

Learning objectives

• Choose and use the appropriate standard units to estimate and measure the length or height of your pumpkin (m/cm/mm)
• Estimate, measure, compare, add and subtract lengths (m/cm/mm), volume (l/ml) and mass (kg/g)
• Recognise when it is possible to use formulae to calculate the volume of shapes

Preparation

Start growing your giant pumpkin with our Pumpkin crop sheet and Grow a giant pumpkin top tips from our RHS pumpkin expert Matthew Oliver.

The table uses total centimetres in reference to the way the pumpkin is measured. It has been found to make the best estimates for the weight of pumpkins.

Equipment

• Tape measure or string
• Measurement table

Step by step

Monster pumpkins need to be weighed using very large scales! Not many people have access to these so you can estimate the weight by using the following method.

In order to estimate the weight of your pumpkin, you need to take three measurements (in millimetres or centimetres) using a measuring tape or string. Look at the diagram below to help you take your measurements.

1. First measure the circumference – measure all the way around the pumpkin at its widest point, keeping your tape parallel with the ground.
2. Then measure side to side – place your tape measure on the ground at the side of your pumpkin at its widest point. Lay the tape over the pumpkin and straight down to the ground on the opposite side.
3. Finally measure stem to base – start your measurement on the ground by the stem. Lay the tape over the pumpkin to the ground at the blossom end (indent in the base of the pumpkin).
4. Add your three measurements together. Look up the total (or the number closest to it) on the table below to find the estimated weight of your pumpkin.

Hints & tips

• Why not explore finding the weight of other 3D shapes (cubes and cuboids) by first calculating their volume
• Can you find out how other giant vegetables might be measured?

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