Water: Life- YouTube

Buoyancy

• Displacement: An object floating or submerged in water will displace a mass of water equal to the mass of the object.

• Buoyancy: A boat’s buoyance is determined by the sum of the weights of the boat and its cargo divided by the volume of the boat.

If the ratio of buoyancy is less than 1, the boat will float. If it is more than one, the boat will

sink.

Whatever Floats Your Boat

• Calculate the weight from a given draft and vice-versa. The vehicle that allows you to do that is volume.

• Volume: length x width x height• Density: Using the density of water, we can

convert volume into mass.• 1 gram of water = 1 mL of water = 1 cm3 of water

Skittles Weigh Boat Lab

Objective: 1. Students will calculate the

draft of a boat using the mass of the cargo.

2. Students will practice calculating the mass of cargo using the draft of the boat.

3. Students will use the unique properties of water to convert volume to mass.

height

lengthwidth

Skittles Weigh Boat Lab

Procedure:1. Measure the length, width and height of your weigh boat.

Record these in your data table. Calculate the volume of your weigh boat. (v = l x w x h)

2. Measure the mass of your weigh boat on a scale. Record it in your data table. Measure the mass of your weigh boat containing 10 Skittles on the scale. Record this in your data table. Divide that mass by 10 to get the average mass of one Skittle. Record it in your data table.

3. Place your empty weigh boat in the water.

Skittles Weigh Boat Lab

Mass of Empty Weigh Boat (g)

Mass of weigh boat with 10 Skittles (g)

Mass of 10 Skittles (g)

Average Mass of 1 Skittle (g)

Height (cm) Length (cm) Width (cm) Volume of weigh boat (mL or cm3)

Mass of displaced water (g)

Weigh Boat Data

Average Mass of Skittles

4. Add 10 g worth of Skittles to your boat and record your draft in your data table. Add another 10 grams and record the new draft. Continue to add Skittles in 10 gram increments, recording the draft, until your data table is complete or your weigh boat has sunk.

5. Remove all the Skittles from your boat and place the empty weigh boat in the water.

6. Add Skittles one by one to your boat until your draft is 0.5 cm. Record how many Skittles you added. Continue to add Skittles to your boat until your draft is 1.0 cm. Record the total number of Skittles your boat is carrying. Continue to do this, in 05 cm increments until you have completed your data table, or your boat has sunk.

7. Convert the number of Skittles to mass, using the mass of one Skittle that you calculated in the first data tables.

Skittles Weigh Boat Lab

Draft (cm)

Cargo (g) 10 20 30 40 50

Calculating Draft Data

Draft (cm) 0.5 1 1.5 2.0

Cargo (g)

Calculating Mass Data

Conclusions and Analysis

8. What is your boat’s maximum cargo mass?9. Graph your data from the charts above.

Before you do, predict what kind of relationship describes the data (linear, curved, or no correlation). After you graph, describe your findings. Is your line straight, or curved?

Penny Canoe

• For any canoe shaped like a triangular prism, the volume of water displaced can be determined by the following formula: V = d²h, where d is the draft (vertical distance under water) and h is the length of the canoe (the keel).

V = d²h V = d²h= d x d x h

• Once you have calculated the volume, you can use the density of water to get the weight.

• 1 gram of water = 1 cm3 of water = 1 mL of water.