Answers to Homework Questions Chapter 1-2

 

Section Review 1-1 (p.10)
    1. The goal of science is to understand the world around us.
    2. Life science deals with living things and their parts and actions. Earth science is the study of the earth and its rocks, volcanoes, earthquakes, oceans, atmosphere and other features. Physical science is the study of matter and energy.
    3. Technological advances may provide answers to our current scientific problems as well as open up new areas of exploration.

 

Section Review 1-2 ( p. 19)
    1. The basic steps in the scientific method are:
      state the problem
      gather information about the problem
      form a hypothesis
      perform experiment to test the hypothesis
      record and analyze data
      state a conclusion
      repeat the work
    2. An experiment must have only one variable. The control setup must vary from the experimental setup in just one way - the variable being investigated should be absent. In this way a scientist can be fairly certain that the variable does or does not cause the results.
    3. Answers may vary. What is the source of the power for the radio? If it is electricity, do other appliances work ? If not, perhaps the problem is in the wall outlet. If so, try plugging the radio into another outlet. If battery operated, try replacing the battery.

 

Section 1-3 (p. 25)
    1. Meter, liter, kilogram, degree celsius
    2. Kilometer - the distance is so large that other units (meter, cm, mm) would be too large; using a smaller unit (light-year) would result in an extremely small number.
    3. There are 10 billion angstroms in a meter.
    4. By determining its density. If the object has a density of less than 1 g/mL, it will float on water.

 

 

Section 1-4 (p. 31)
    1. 125 cm3
    2. Length: meterstick; mass: balance; volume: graduated cylinder; temperature: Celsius thermometer.
    3. Find its mass using a triple beam bakance. Find its volume using a graduated cylinder and the volume displacement method. Use the formula Density = Mass¸ Volume

 

Section Review 1-5 (p.32)
    1. Follow the teacher's directions or the directions in your lab procedure exactly.
    2. They could splash or boil out and injure someone.
    3. On the wall beside the filing cabinets in the back of the room

 

Chapter 1 Review

Multiple Choice
    1. B. scientific method
    2. D. hypothesis
    3. D variable
    4. C. meter
    5. B millillter
    6. A kilogram
    7. C. mass
    8. B. triple beam balance
    9. A milliliters
    10. C. follow directions

 

True-False
    1. F, one variable
    2. T
    3. T
    4. F, one thousand
    5. F, 1000 milliliters
    6. F, kilograms
    7. F, mass, volume
    8. T
    9. F, middle beam
    10. T

 

Concept Mapping

Row 1: density

Row 2: milliliter, cubic centimeter

Row 3: kilogram, gram

 

Concept Mastery
    1. Without a standard system of measurement, scientists all over the world cannot be sure that they are comparing their data accurately. They cannot transmit data and be sure that the data are being transmitted accurately.
    2. The steps are:
      state the problem
      gather information about the problem
      form a hypothesis
      perform experiment to test the hypothesis
      record and analyze data
      state a conclusion
      repeat the work
    3. A millimeter, one thousandth of a meter, might be used to measure the thickness of lead in your pencil (0.5mm, 0.7mm); a centimeter, one hundredth of a meter, might be used to measure the width of your fingernail; a meter, the standard unit of metric length, might be used to measure the length of your classroom; a kilometer, one thousand meters, might be used to measure the distance you travel on vacation
    4. Density is defined as the mass per unit volume of a substance. Density is an important component in a scientist's effort to define, name, and classify various substances.
    5. No conversion factor equaling one exists for the conversion of kilograms to meters.
    6. The distance to the stars must be equal or greater than 5 billion light years.

 

Critical Thinking and Problem Solving
    1. A) graduated cylinder or measuring cup; liter or milliliter
      B) meterstick, centimeter
      c) triple beam balance, kilogram
      d) meterstick, meter
      e) graduated cylinder, milliliter or cubic centimeter
      f) triple beam balance, gram
      g) celsius thermometer, degree celsius
    2. A) 33 m x 100cm/m = 3300 cm
      b) 45 m x 1000 mm/m = 45000 mm
      c) 8.8 km x 1000 m/km = 8800 m
      d) 2.5 g x 1000 mg/g = 2500 mg
      e) 6300 kg x 1000g/kg = 6,300,000 g
    3. This statement says that the mass of an object is determined by the amount of matter in an object. Cut the object in half and the amount of mass is also reduced in half. Density, however, is a characteristic of a particular material. Each substance has a particular density, and doubling or changing the size of the substance will not change the density of the substance
    4. Experiments might include obtaining a triple beam balance and a graduated cylinder to determine the density of the substance. If the density is 19.32 g/cm3, then the substance is gold. If the density is not 19.32 g/cm3, the substance is not gold.
    5. Letters should contain a clearly defined position as to whether or not the US should convert to the metric system.

 

Section Review 2-1 ( p. 42)
    1. Matter is anything that has mass and volume.
    2. Mass, weight, volume, and density
    3. Descriptions should use terms discussed in this section

 

Section Review 2-2 (p.48)
    1. Mass is the amount of matter in an object. Weight is the measure of the pull of gravity on an object.
    2. The greater the mass, the greater the inertia.
    3. You would weigh less on the moon; mass would be the same in both places.

 

Section Review 2-3 (p. 54)
    1. Density is defined as mass per unit volume.
    2. An object with a density greater than water's density ( 1 g/mL) will sink in water while an object with a density less than 1 g/mL will float in water.
    3. Helium's density is less than the density of air.

 

 

Chapter 2 Review

Multiple choice
    1. D. general properties
    2. B mass
    3. C mass remains unchanged
    4. C mass/volume
    5. B its weight decreases
    6. A volume
    7. B inertia
    8. D gravity

 

True or False
    1. T
    2. F, inertia
    3. F, 1000
    4. F, mass, weight, volume, & density
    5. F, volume
    6. F remains the same
    7. T
    8. F, less

 

Concept mapping

Row 1: general properties

Row 2: weight, density

 

Concept Mastery
    1. The fuel provides the force that propels the rocket upwards. because the gravitational pull on the moon is less than that of the earth, the rocket will need less force (hence, less fuel) to escape the moon's pull of gravity
    2. Although the force of the earth's gravity is reduced in space, the astronauts are not weightless as they are still being pulled toward the earth by its gravity.
    3. The density of salt water is greater than the density of fresh water.
    4. The overall density of the boat must be less than 1 g/mL
    5. The fish can regulate the amount of air in its swim bladder and thus change its density so that it can remain at any given level in the water
    6. On the moo the ballerina's weight is less than it was on earth
    7. When water freezes, its molecules become more spread out and arranged to form crystals, Ice, therefore is less dense than liquid water, Because ice is less dense, it floats.
    8. Because oil is less dense than water, it floats o the surface instead of sinking. If you try to mix oil and water, they will separate into layers as soon as you stop stirring or shaking them.

 

Critical Thinking and Problem Solving

 
    1. The volume and weight of the first sample is less than the second. The densities are equal.
    2. Because the same amount of cereal can be placed in different size containers, consumers cannot really know how much they are purchasing by the size of the container. If consumers know the mass of the cereal, they can evaluate how much they are purchasing for a particular price.
    3. 0.78 g/cm3 x 4.0 cm3 = 3.12 g = 3.1 g (sig figs) This object will float in water.
    4. Design should be consistent with the scientific method. You may have designed an experiment to determine the density of the sample and compare it to the sample of pure gold.
    5. Aluminum is less dense than cast iron.
    6. Poems should be consistent with the chapter content.

 

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