Chapter 3 Review Study Guide

1) Define: Density: Mass: The amount of matter in an object Weight: The gravitational force exerted on an object. Volume: The amount of space taken up by an object. Density: Mass per unit volume Buoyant force: An upward force on an object in a fluid Density: Which one is more dense?

2) A solid rubber stopper has a mass of 33. 0 grams and a volume of 30 2) A solid rubber stopper has a mass of 33.0 grams and a volume of 30.0 cm3. What is the density of rubber? d=m/v d= 33.0 g/30.0 cm3 d= 1.1 g/cm3

3) A larger solid rubber stopper has a mass of 49 3) A larger solid rubber stopper has a mass of 49.5 grams and a volume of 45.0 cm3. Calculate the density. Did it change? Why? The density is still 1.1 g/cm3 Why?? Density does not change with the size of the sample. As long as you are measuring the same substance, the density will always be the same.

4) If the mass of an object is 5g and it is 2cm wide, 10 cm tall, and 2cm long, what is its density? d=m/v v=lxwxh d=5g/40cm3 V=40 cm3 d=0.125 g/cm3

1 g/cm3 = 1 g/mL 1000 kg/m3 = 1000 kg/L Pressure: Pa (pascal) 5 and 6) What are the units used for density? What are the units for pressure? 1 g/cm3 = 1 g/mL 1000 kg/m3 = 1000 kg/L Pressure: Pa (pascal)

7) List the steps needed to find the density of a toy car. Record volume of water Place object in water and record combined volume. Find the difference between the ending volume and the starting volume to find out how much water was displaced. The amount of displaced water is the volume of the toy car. Find the mass of the object. Use the density equation to calculate.

8) Do Buoyant forces refer to the weight of an object or the mass of an object? Explain The weight, because buoyant forces are affected by gravity and weight is the gravitational force on a object. Since weight and gravity are closely related, and the only vertical forces at work are buoyancy and gravity, weight is what matters.

9. How are pressure and force related? P=F/A If you increase the area where the force is being applied, the pressure will decrease.

10) Why do boats float? Reflect on your boat lab. Boats can float only if their volume is increased enough to displace a greater amount of water than it would if it were crumpled in a ball.

11) Explain Archimedes’ Principle in your own words. The buoyant force on an object is equal to the weight of the fluid the object displaces. Pulling cards…

12) Why is Archimedes’ Principle useful? You tell me! (Pulling cards…) Just to name a few: Helps us find volume of things we don’t have a formula for. Helps us understand how fish, submarines, and scuba divers can control their depth. Helps us understand how boats float.

When an object is floating, buoyant force and weight are balanced. 13. Describe the forces (Buoyant force, weight) of a floating object and a sunken object. Are these forces balanced or unbalanced? When an object is floating, buoyant force and weight are balanced. When an object sinks, weight (a downward force) is greater than buoyant force. These are unbalanced.

Do we have time for a… Vocab challenge?

The gravitational force exerted on an object The gravitational force exerted on an object. It is a force that points toward the center of Earth. Weight

Mass per unit volume (g/cm3) Density

Use to measure a liquid's volume. Graduated Cylinder

Amount of matter in an object. Does not change with location. Mass

An upward force on an object in a fluid exerted by another fluid An upward force on an object in a fluid exerted by another fluid. Buoyant Force

The buoyant force on an object is equal to the weight of the fluid the object displaces. Archimedes’ Principle

Is the curve in the upper surface of a liquid close to the surface of the container, caused by surface tension. Meniscus

The amount of space taken up by an object. Volume