Mathematics Activity

Measuring Manducas

by

Patricia Weaver, Drachman Elementary School, Tucson, AZ

You 'll need

• a centimeter ruler
• a balance or scale for weighing
• a piece of string
• scissors
• paper clips or other small weights
• Measuring Manducas data sheet
• Manduca Growth Chart

Directions

Weight

1. Record the date
2. Estimate how much the Manduca weighs. Record your estimate on the data sheet.
3. Measure how much the Manduca weighs. Record the weight on the data sheet.

Length

1. Estimate how long the Manduca is. Record your estimate on the data sheet.
2. Measure how long the Manduca is. Record the length on the data sheet.

How big around?

Circumference is a word that means "how big around".

1. Estimate the Manduca's circumference. Record your estimate on the data sheet.
2. Cut a piece of string that is big enough to go around the Manduca Carefully put the string around the Manduca.
3. Cut off any extra string.
4. Tape the string to the data sheet.
5. Measure the string and record its length (the circumference)

 

Volume

Another way to measure "how big" a Manduca has grown is to measure its volume. The easiest way to do this is to measure the amount of water the larva displaces when you put it in a container of water.

Use a graduated cylinder and record the water level, in milliliters,with and without the larva. Subtract the "before" from the "after" to find the volume of the larva. Insects don't breathe the same way that humans do, so it doesn't harm the larva to submerge it in water, even for a few minutes. (Please don't leave it there though!)

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