Question

student exploration: measuring volume
vocabulary: cubic centimeter, diameter, graduated cylinder, meniscus, milliliter, pipette, radius, rectangular prism, sphere, volume, water displacement
prior knowledge question (do this before using the gizmo.)
albert plays football. his sister juliana plays volleyball. while walking home from practice one day, albert and juliana argue about which is bigger, a football or volleyball.
how would you measure and compare the sizes of the two balls?
gizmo warm - up
when scientists talk about how big something is, they are really talking about its volume, or the amount of space it takes up. the measuring volume gizmo allows you to measure the volumes of liquids and solids using a variety of tools.
to begin, remove the 50 - ml graduated cylinder from the cabinet and place it below the faucet. to turn on the faucet, drag the slider next to the faucet up. fill the cylinder about halfway, as shown.

1. place the magnifier over the waterline. draw a sketch of what you see in the area at right. label the large tick marks on your sketch.

what volume is represented by each small tick mark?

1. what is the shape of the waterline?

this curved shape is called the meniscus. always read the volume at the bottom of the meniscus.

1. what is the volume of water in the graduated cylinder?

Explanation:

1. For the tick - mark volume:

• A 50 - mL graduated cylinder is used. If the large tick marks are, for example, at 10 - mL intervals (common in many 50 - mL cylinders), and there are 10 small intervals between two large tick marks. Then the volume per small tick mark is calculated as \(\frac{10\space mL}{10}=1\space mL\).

1. For the waterline shape:

• Due to surface tension, the water in a graduated cylinder forms a concave - up shape, which is called a meniscus.

1. For the water volume:

• Read the volume at the bottom of the meniscus. If, for example, the bottom of the meniscus aligns with the 25 - mL mark (assuming a standard 50 - mL cylinder with appropriate markings), then the volume is 25 mL.

Answer:

1. If the large tick marks are 10 - mL apart and there are 10 small intervals between them, each small tick mark represents \(1\space mL\).
2. The shape of the waterline is concave - up (meniscus - shaped).
3. Assuming the bottom of the meniscus is at the 25 - mL mark (a common half - way mark for a 50 - mL cylinder), the volume of water is \(25\space mL\).