Life Through a Lens Lesson 2 Review

With the heater on, Darcy’s living room should be a comfortable 19°C. But the room only reaches 16°C, which is too cold. Darcy realizes that warm air is escaping through a gap underneath the door. She decides to make models of a device called a draft excluder (a fabric tube stuffed with foam) to attempt to keep the warm air inside the room and the cold air outside. She makes 3 models of different thicknesses and tests them.

What is the independent variable in her experiment?

• The temperature of the room.

• The temperature outside.

• The thickness of the draft excluder.

• The temperature of the heater air.

With the heater on, Darcy’s living room should be a comfortable 19°C. But the room only reaches 16°C, which is too cold. Darcy realizes that warm air is escaping through a gap underneath the door. She decides to make models of a device called a draft excluder (a fabric tube stuffed with foam) to attempt to keep the warm air inside the room and the cold air outside. She makes 3 models of different thicknesses and tests them.

What is the dependent variable in her experiment?

• The temperature of the room.

• The temperature outside.

• The thickness of the draft excluder.

• The temperature of the heater air.

Darcy makes two draft excluders using different thicknesses of foam. One is 20 mm thick and the other is 40 mm thick. She tests the 20 mm draft excluder one night and the 40 mm draft excluder the next night. She collects the following data from her investigation.

Which statement best explains the relationship between the thickness of the draft excluder and energy transfer?

• The 20 mm draft excluder allowed the greatest amount of energy to leave the living room, shown by the greatest increase in temperature after 1 hour.

• The 20 mm draft excluder allowed the smallest amount of energy to leave the living room, shown by the greatest increase in temperature after 1 hour.

• The 40 mm draft excluder allowed the greatest amount of energy to leave the living room, shown by the greatest increase in temperature after 1 hour.

• The 40 mm draft excluder allowed the smallest amount of energy to leave the living room, shown by the greatest increase in temperature after 1 hour.

Darcy wants to improve her design to better meet her criteria: her design should not allow the temperature in the living room to go below 19°C. She cannot create an expensive device. She collects additional data on costs of different materials.

Which design improvement could Darcy make to better meet her criteria while also meeting her constraint?

• Stuffing the draft excluder with foam to a thickness of 60 mm

• Adding an electronic heating element to the draft excluder

• Replacing the foam with recycled paper to a thickness of 50 mm

Abilash sets up an investigation using cold water and hot water. He puts three drops of red food dye in each tumbler and waits ten seconds. His results are shown in the photo.

How can he describe the relationship between the temperature of the water and the energy of the water molecules in the system?

• The lower the temperature of the water, the greater the amount of energy in the system and the faster the water molecules move.

• The higher the temperature of the water, the greater amount of energy in the system and the faster the water molecules move.

• The higher the temperature of the water, the lower amount of energy in the system and the slower the water molecules move.

• The temperature of the water has no effect on the speed of the molecules, so the amount of energy in the system does not change.

Ally’s car becomes uncomfortably hot during the summer if she can’t park it in the shade. She wants to design a cover for her windshield to keep the car cool when she has to park it in the sun. She can only spend $10 on materials and has one week to make a prototype.

Which is a criteria of this design?

• Must cost less than $10.

• Must keep car interior at 20 degrees Celsius.

• Must be finished within one week.

• Must match her car's paint job.

Ally’s car becomes uncomfortably hot during the summer if she can’t park it in the shade. She wants to design a cover for her windshield to keep the car cool when she has to park it in the sun. She can only spend $10 on materials and has one week to make a prototype.

Which are constraints of this design? (Choose 2)

• Must cost less than $10.

• Must keep car interior at 20 degrees Celsius.

• Must be finished within one week.

• Must match her car's paint job.

Which material should Ally use to keep her car cool based on her investigation?

• Vinyl

• Silk

• Mylar

• Polyester

What does Ally's investigation show about the effect of different materials on temperature?

• Materials affect the temperature

• Materials do not affect the temperature

• Materials increase the temperature

• Materials decrease the temperature

In Ally's investigation, which material caused the most change in the energy in the kinetic store of the air particles?

• Vinyl

• Polyester

• Mylar

• Silk