Alchemy Quiz 02

A block and a cylinder are put on either side of an equal-arm balance. The block goes down and the cylinder goes up. What can this observation alone tell us about the two objects?

• The block has larger volume and mass.

• The block has larger mass and density.

• The block has larger volume, mass and density.

• The block has larger mass only.

• The block has larger volume only.

Answer explanation

A double pan balance can be used to compare mass only.

Tags

NGSS.MS-PS2-4

A block and an egg are placed into identical graduated cylinders as shown in the pictures. The water level rises by the same amount in each cylinder. Based on this measurement alone which property (or properties) can be concluded to be the same for the block and the egg?

• mass only

• volume only

• density only

• mass and volume

• volume and density

Answer explanation

When an object is completely submerged (underwater), the change in the water level represents the volume of the object that was added to the water.

The two objects shown below are put on either side of an equal-arm balance. The balance remains level. Based on this observation alone which property (or properties) of the two objects must be the same?

• mass only

• volume only

• volume and mass

• mass and density

• mass, volume, and density

Answer explanation

A double pan balance compares the masses of the two objects. If the balance is level, the masses are the same.

A block and a ball are placed into graduated cylinders as shown in the pictures. The water level rises higher in the cylinder in which the ball is placed. Based on this measurement alone which quantity or quantities are larger for the ball?

• mass only

• volume only

• density only

• mass and volume

• mass, volume, and density

Answer explanation

If an object sinks, the amount of water it displaces is the volume to the object.

The diagram shows two irregularly shaped swimming pools. Which of the methods listed below could be used to find which pool has the greater surface area?

• Measure and then multiply the (Length) x (Width) of each pool.

• Float basketballs on each pool. The pool that holds more floating basketballs has larger area.

• Completely fill each pool with bowling balls. The pool that holds more bowling balls has a larger area.

• Measure the amount of water needed to fill each pool. More water means more surface area.

• Measure the distance around each pool. The pool with the bigger distance around it has the larger area.

Answer explanation

The area of objects with an irregular shape cannot be determined with a formula. You can estimate the area with standard objects that float on the surface of the pool, estimating the partial contributions of parts that cannot be completely covered.

What is an operational definition for the mass of an object?

• The amount of matter that makes up a body.

• The number of milliliters of water that an object displaces.

• How heavy something is.

• The amount of space that something takes up.

• The number of standard units that balance an object.

Answer explanation

A dictionary definition is NOT an operational definition, which is a procedure for finding the value of a property.

The diagrams show 15 mL of water in one graduated cylinder and a rock sample in another. How can you use one or both graduated cylinders to determine the volume of the rock sample?

• Additional equipment is necessary to determine the volume of the rock sample.

• Pour the 15 mL of water into the second graduated cylinder and read the water level.

• Pour the 15 mL of water into the second graduated cylinder and subtract 15 mL from the resulting water level.

• Read the mark at eye level on the second graduated cylinder that is at the same height as the very top of the rock sample.

Answer explanation

If an object can fit inside a graduated cylinder and if it sinks, the change in the water level will indicate the volume of the object.

Sally needs to determine the volume of 4 objects; a cube, a block, a cylinder and a sphere. For which of these objects can she use the formula: volume = (length) x (width) x (height)?

• only the cube

• only the block

• the cube and the block

• the cube, the block, and the cylinder

• all four objects

Answer explanation

The volume formula L x W x H can only be used on an object with rectangular shape.

A large cube is built up from several smaller cubes. Each of the small cubes is the same size. The small cube in the upper right front corner is moved to the top of the structure as shown.  Which of the following statements is most accurate about the properties of the large cube when the corner block is moved?

• The mass and volume increase.

• The volume and surface area increase.

• The mass and surface area increase.

• The volume increases.

• The surface area increases.

Answer explanation

The volume of the object never changes, because the number of standard cubes remains the same. If you expose more sides of those standard cubes, the surface area will increase.

A magician says:  "I can recover lost coins from the sea. Give me a coin. I will toss it into the sea and then recover it." Before giving the coin to the magician, you place it on your balance. You obtain a mass measurement of 43.16 g. The coin seems to be tossed into the sea and then to reappear in a flourish of the magician's hand. You wipe off the coin, then place it on your balance and obtain a mass measurement of 43.17 g. We will assume you have measured correctly both times. Could the magician have returned the same coin?

• If the uncertainty of the balance is equal to or greater than 0.01 g, the coins could possibly be the same.

• It’s just not possible to retrieve a coin tossed into the ocean.

• The masses are different, so the coins must be different.

• We would need to know the density of the coins to determine if they are made out of the same material.

Answer explanation

Remember that there is random error in any measurement, even if the the measuring devices and procedures are correct. A difference of 0.01 is within the range of reasonable uncertainty for the same object.