When an ultrasound is taken of an unborn child, a photograph is produced. We all know that in reality, the baby in the photograph is much smaller than in real life within the womb. However, there is...

When an ultrasound is taken of an unborn child, a photograph is produced. We all know that in reality, the baby in the photograph is much smaller than in real life within the womb. However, there is something special about the picture - it has been drawn "to scale".

If you could measure the length of the baby's foot in the womb and compare it to the length of the foot in the photograph, you will get the same ratio as if you measured the baby's arm in the womb and compared it to the baby's arm in the photograph. This is because the ultrasound produces ascale drawing.

Scale drawings are used to provide information on a small piece of paper about large objects like buildings, roadways, the earth, people and such. To achieve this, the actual size of the item is scaled to fit on the paper. This means, each line drawn on the paper must be in the same ratio to the corresponding side of the actual item.

For this discussion, you get to explore scale drawings.

1. Find out more about how scale drawings are created and used here:
   
   
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     What is a Scale Drawing?
     
   
   
   
   


2. Take a photograph of anyone or any item around you. Now get out your tape measure or ruler.


3. If is is a person, measure the person's arm. If it is an item, measure one side of it. Take the same measurement in your photograph and record the measurement on your photograph.


4. Calculate the ratio between the measurement in the photograph and the measurement in real life.


5. On the photograph, measure a different part of the same body, or a different side of the same item. Show this second measurement on your photograph.
   


6. Take the same second measurement in real life. Calculate the ratio between the second measurement in the photograph and the second measurement in real life.


7. Answer the following questions in your post this week:
   
   
   1. What is the first real-life measurement you made of your item above?
   
   
   2. What is the corresponding measurement in your photograph?
   
   
   3. What is the ratio of the photograph measurement to the real-life measurement?
   
   
   4. What is the second real-life measurement you made you made above?
   
   
   5. What is the corresponding measurement in your photograph?
   
   
   6. What is the ratio of the photograph measurement to the real-life measurement (for the second measurement).
   
   
   7. The ratios should be the same since the photograph is a scaled image. Are yours the same? Why or why not?
   
   
   
   


8. Attach your photograph (only one photograph) here showing all the measurements on the same photograph.