At-Home Activities

Identify a toy that uses a fluid to work. (Remember that air is a fluid!) Describe to family members how the toy works.

Conduct this lesson's Try This activity at home. Compare your home flow rate with the flow rate obtained at your school.

Look around your home for examples of turbulent and laminar flow. What evidence is there of each?

Plan and carry out and test to compare the viscosity of two of the following substances: shampoo, melted chocolate, cooking oil, air and cola. Record your observations and conclusions.

Pour corn oil or molasses into a 5 mL measuring spoon and observe what happens. Next, place the container of corn oil or molasses in the refrigerator overnight. Try to pour the liquid into a 5 mL spoon again. Record your observations. What does this tell you about the viscosity of these liquids when heat is removed?

Find out if any of your family members or family acquaintances works in an industry in which viscosity is important and, if so, in what way.

Record the volume capacity of a variety of common household items. Categorize the containers according to capacities of approximately 250 mL, 500 mL, 1L and 2L.

Measure 125 mL of butter using the displacement method. First, fill a measuring cup with water to the 125 mL mark. Then add chunks of cold butter until the water rises to the 250 mL mark. List some other substances that could be measured using the displacement method.

n/a

Fill a greasy frying pan half-full of water. Be sure the pan is not hot! Observe the globules of fat that float in the water. Squirt a few drops of dish soap into the pan. What happens to the grease? Why? Does this lead you to any conclusions about how to clean up oil spills?
(The fat is floating on the water because it is less dense than water. Soap breaks the bonds that hold the molecules together, breaking the surface tension of the liquid.)

Is hot water less dense than cold water? Find out by doing the following:

1. Fill a tall glass with very cold water.
2. Find a small bottle, such as a plastic pill bottle, which can easily fit into the tall glass. Use a strong elastic band to attach a Popsicle stick to each side of the small bottle. (You will use the sticks to lower and stabilize the small bottle when it is in the tall glass.)
3. Fill the small bottle with boiling water, being careful to avoid burns.
4. Add a few drops of food colouring to the small bottle.
5. Lower the pill bottle into the glass using the sticks as handles to keep it upright.

What do you observe?
(The coloured water in the small bottle streams out and rises to the top of the glass, floating at the top of the cold water. The molecules of hot water are vibrating more and moving further apart, making the liquid less dense.)

Find out whether lava floats. Locate a barbecue brick made of lava (these are quite common) and test it's buoyancy in a pail of water.

Are the densities of cola and diet cola the same? Measure the mass of a can of cola and a can of diet cola. Using the volume listed on the labels, calculate the density of each. Test the buoyancy of each can and record your observations. Explain your findings using words such as mass, buoyancy, density and volume. (Cola has a greater mass and higher density than diet cola due to its dissolved sugar content. Although the volume of the two cans is the same, the higher mass causes the cola can to sink.)

Try layering tap water with a saturated solution of salt water. Add food colouring to the salt solution. Pour very slowly. Draw your observations.

Make a Cartesian Diver.

1. Use a 2L plastic pop bottle, water and a medicine dropper.
2. Fill the pop bottle with water to within
   10-15 cm from the top.
3. Drop in the medicine dropper so that it floats upright.
4. Cap the bottle tightly.

What happens when you squeeze the bottle? What happens when you release the bottle? Record your observations and explain your findings in relation to density and buoyancy.
(When the "diver" is floating at the surface of the water, its total mass is supported by the buoyant force of the water. Squeezing the bottle forces more water into the dropper, compressing the gas inside. This decreases the volume of the entire dropper, but leaves its mass unchanged. Therefore, its density increases. Now the mass of the medicine dropper and the water inside it are too large to be help up by buoyant force and the diver sinks. When you release the bottle, the gas in the dropper is no longer compressed, so it forces the water back out and the density returns to normal. The diver floats back to its original position.)

Discuss with family members what you have learned about the issue of zebra mussels in the Great Lakes and associated waterways and ask their opinions. Have zebra mussels been beneficial or harmful? Should we be concerned that the ballast from commercial shipping may pollute our waters?

Locate an empty 355 mL plastic water bottle. Remove the cap and place a balloon over the top of the bottle, ensuring that the lip of the balloon fits tightly around the bottle. Place the bottle upright inside a large (2-4 L) measuring cup or heatproof bowl inside a sink. Carefully pour boiling water around the bottle. Observe what happens to the balloon. Use the particle theory to explain what happens.
(When boiling water is poured around the bottle, the air inside heats up. The particles move more quickly because of the increased energy. They overcome the forces of attraction enough to begin escaping as a gas and begin to inflate the balloon. Gas particles will spread out to fill their container.)

Discuss with family members some of the bridges you know about or see frequently. What are the structural features? Are there any problems with the bridge design? Are there any factors that must be considered during the winter and summer?
(Triangulation is a feature of many bridges. Traffic congestion caused by a narrow span, and bridge closures due to high winds or winter ice are significant problems related to bridge design. Boat traffic often causes lift bridges to hold up automobile traffic. These potential problems are part of the design considerations that engineers must take into consideration.)

Survey family members and acquaintances to identify industries that use fluid power.

Look around your home for examples of confined fluids under pressure.

n/a

Make your own aerosol sprayer. Fill a glass with water. Place a straw, cut to just break the surface of the water by about 1 cm, into the water. Hold a second straw vertically to blow across the top of the first straw. You should start a fine mist spraying from the first straw. (Be patient. It takes time to get the flow of air right.)

Survey your family members and adult acquaintances to produce a list of jobs in which hydraulic and pneumatic systems play a role.

Identify one hydraulic and one pneumatic system in use in your home. Write a paragraph about how each one is used.

Note to parents: Since the Design Challenge may be used by teachers as a performance assessment opportunity, parents should consult with the teacher to determine the appropriate degree of parental involvement in their child's completion of the Design Challenge.

The Unit Summary in your textbook lists all the learning expectations you have covered in the unit and identifies the specific lessons in which the knowledge and skills have been developed.

You can use the Unit Summary to help you create a personal study guide in preparation for an end-of-unit test:

1. Copy down the list of learning expectations from your textbook. These are grouped under three headings: Understanding Concepts, Applying Skills, Making Connections.
2. . For each learning expectation, locate the appropriate lesson(s) in the unit where the expectation was covered. These are found at the end of each expectation (e.g., 2.1).
3. Flip to the appropriate lesson(s) for each expectation and make study notes of the key ideas or skills you learned.