Welcome to the weekly Science Picture Quiz
Welcome to the Science Weekly Picture Quiz!
This picture has scientific or technological significance.
Can you work out what it is?
The answer will be posted on Friday morning. Good luck!
If you're looking for an extra challenge, try the first online treasure hunt here!
Week 30 Answer:
Did you realise those are bananas going into the metal box? And did you track down why?! Congratulations if you worked out the box is a calorimeter and these bananas were part of Wilbur Olin Atwater's pioneering work on nutrition!
A calorimeter is a piece of apparatus for measuring the energy given out in chemical reactions. In the experiment in the photo, the bananas were burned inside the calorimeter and this heated water of a known mass and initial temperature. By measuring the final temperature of the water, the scientists could work out how much energy the water had gained and hence estimate the energy contained in the bananas. Atwater worked out the energy contained in a huge range of foods and also carried out research on the other nutrients foods contain.
Atwater also carried out experiments with a respiration calorimeter. This was a large, sealed chamber that a person climbed into. As well as measuring the increase in air temperature inside the chamber, the respiration calorimeter measured the amount of carbon dioxide in the air. These measurements allowed Atwater to calculate how much energy people were using, while they were inside the chamber. He used the respiration calorimeter to work out the energy expenditure of people carrying out activities, such as sleeping and jogging, but also ironing and knitting!
Credit: USDA National Agricultural Library