Weighing the perfect pumpkin

A 124 kg pumpkin and me.

A 124 kg pumpkin and me.

Every job has its ‘perks’. And being asked to help Andrew Hanson adjudicate at the weigh-in of the pumpkin competition of the Royal Paddocks Allotment Society in Hampton Wick is definitely a ‘perk’. It might even be an honour.

Normally we put the pumpkins into a large ‘IKEA’ bag and lift up the bag with two luggage scales – each capable of weighing 50 kg. We then add the results together to find the total weight.

This year we were faced with an unprecedented challenge which we met with a combination of new technology and ingenuity. The new technology was some 100 kg parcel scales with a remote readout. These were fantastic and very easy to use.

But we knew we had a problem when the first large pumpkin weighed in at 24 kg. Then the next two ‘biggies’ weighed in at 87 kg and 95 kg respectively. All this made it obvious that the ‘Great White Pumpkin’ was going to weigh more than 100 kg. We tried it, and sure enough, the scales overloaded and switched themselves off. So how could we weigh the ‘Great White’?

The pumpkin in teh wheelbarrow at the back weighed 25 kg. Teh two 'large' orange pumpkins weighed 85 and 95 kg. But how  could we weigh the big one?

The pumpkin just visible in the wheelbarrow at the back weighed a  very creditable 25 kg. The two ‘large’ orange pumpkins weighed 87 kg and 95 kg. The ‘Great White Pumpkin’ obviously weighed more than 100 kg But how could we weigh it?

The solution was to combine the new parcel scales with the old luggage scales and team of expert lifters. We first manouevered ‘Moby kin’ onto the luggage scales in its large bag. We then slid an IKEA bag underneath and completed a belt around the beast’s underbelly with a camera strap. We then attached the luggage scale to the strap.

A carefully synchronised procedure was then implemented:

  • First the luggage scale was switched on, zeroed, and left unstressed on the top of the beast.
  • Then the expert lifting team raised ‘Moby kin’ off the scales allowing them to be zeroed
  • The team then lowered the weight onto the scales until the weight read approximately 90 kg.
  • Then two people gradually took the residual weight of the pumpkin with the luggage scales.
  • Then the two scale were read simultaneously, and the sum was our estimate for the weight of the pumpkin.

The uncertainty of measurement was larger than for the other pumpkins – probably around 2 kg –  but it was still pretty clear which pumpkin had won. And then we all had some tea and cake. All in all a very pleasant Sunday lunchtime.

How to weigh a large pumpkin.

How to weigh a large pumpkin.

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3 Responses to “Weighing the perfect pumpkin”

  1. Dominic Says:

    Could you have lowered it into a tank of water to ascertain its volume, then used a general assumption about pumpkin density to calculate the weight? Are pumpkins bouyant in water?

    • protonsforbreakfast Says:

      We could indeed have lowered it into a tank of water had such a thing been available. But there were a lot of people watching and we needed a solution right there and then.


  2. How do you weigh a pumpkin? - Ask a scientist Says:

    […] Find out how they got on over at Michael’s blog. […]

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