SCIENCE INVESTIGATIONS MIDTERM STUDY GUIDE
Name:___________________________________________________________ period:_______
Scientific Method
1. Define the following parts of the scientific method:
a. Procedure- Describes the steps to follow in an experiment
b. Hypothesis- A proposed solution or an educated “guess” (usually writted in “if” , “then” format)
c. conclusion – a decision reached about an experiment based on data collected.
d. variable – something that is changed in an experiment, the factor being tested
e. Constants – factor that stays the same in both the experimental group and control group
2. For the following examples, state whether they are qualitative or quantitative observations:
a. Red in color ________Qualitative____________________
b. 3 meters long ________Quantitative___________________
c. 55.75 grams ________________Quantitative____________
d. Tastes sour ________Qualitative_____________________
Tables and Graphs
3. Define the following types of graphs:
A. Bar- for showing info collected by counting
B. Line- to show trends or continuous change
C. circle/pie- to compare parts of a whole, percentages
4. Why would you draw a line of best fit on a graph?
To show the average of your data and show a trend
5. What is an independent variable? Which axis on a graph would you use for the independent variable? The
variable controlled by the experimenter, plotted on the X-axis (horizontal)
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6. What is a dependent variable? Which axis on a graph would you use for the dependent variable?
The variable that is dependent on the manipulated (independent) variable. (This is the “data” you
collect) Plot this in the Y axis (vertical)
7. What do the dots on a graph represent?
data points
Lab Skills
8. What are three methods for determining volume? (hint: one you would use for a cube, the other
for a marble, and the other for a liquid)
1. LxWxH- for a “regular” solid (like a cube) you can just measure and multiply the length times the width
times the height. Units are cm3
2. Water Displacement- for irregular objects or liquids- Units are mL.
3. Reading the graduated cylinder
Atoms, Isotopes, Periodic Table
9. What is the octet rule for electron dot symbols?
All atoms want 8 electrons in the outer shell
10. What are valence electrons?
The electrons in the outermost shell. (these are the electrons that will form ionic and covalent
bonds)
11. What are the most basic building blocks of all matter?
atoms
12. Why are most atoms electrically neutral?
Protons = electrons
13. Draw an electron dot diagram for:
a. Lithium
b. Sulfur
c. Chlorine
d. Argon
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A neutral atom has a mass number of 25 and 12 protons.
14. How many neutrons does it have? ____13____
15. What is its atomic number? ____12__
16. How many electrons does it have? __12______
17. What is its chemical symbol? ____Mg___
18. If you found another atom of this element with one less electron than the atom described above,
what would it be called? Ion DON’T NEED TO KNOW YET!!!
19. If you found another atom of this element with one more neutron than the atom described above,
what would it be called? isotope
20. Where are nonmetals located on the periodic table?
Right side of periodic table
21. Where are metals located on the periodic table?
Left side of periodic table
22. Name an element that would have characteristics similar to Ca (atomic #20)?
Be, Mg, Sr, Ba, Ra
23. Which family on the periodic table has 8 valence electrons? Noble gases
24. Label the following as a characteristic of a metal or a nonmetal:
a. Conduct electricity ___Metal________
d. Dull
b. Brittle (not malleable)
e. Malleable _________metal_________
___NM_____
_____NM_____________
c. Shiny _________Metal_________
Properties of Matter
25. What is the density of water? ____1.0 g/mL_______
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26. How can you determine if something will sink or float in water?
If its density is greater than 1 g/mL it will sink, if it is less it will float
27. Compare and contrast: mass vs volume
Mass is the amount of matter in an object (measured in grams) and volume is the amount of
space an object takes up (measured in mL or cm3)
28. What is a chemical property? Name a few examples.
A property that can only be observed by doing a chemical reaction (ex- flammability, alkalinity)
29. What is a physical property? Name a few examples.
A property that can be observed with the 5 senses (color, height)
30. Explain why muddy water is considered a heterogeneous mixture.
a. Mixture because particles are not chemically bonded together
Hetero because- Particles are larger, are not the “same throughout”
31. Compare the following:
a. Pure Substances vs Mixtures- pure substances are chemically bonded, and mixtures are only
physically mixed.
b. Elements vs Compounds- elements are made of only one type of atom (one element) and
compounds have two or more elements bonded together.
c. Heterogeneous vs Homogeneous Mixtures
Both are physically mixed, but hetereogeneous mixtures have larger particles, are not
the “same throughout” and show the tyndall effect.
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Phases of Matter/ Energy
32. Which state of matter is described below? (Solid, Liquid, or Gas)
a. Has definite volume and definite shape ______solid______
b. Has no definite volume, no definite shape and no charge ____gas________
c. Has definite volume and no definite shape _____liquid_______
d. Has the most kinetic energy _____gas_______
e. Has the most attractive forces (IFs) between molecules _______solid__________
f. Has the least attractive forces (IFs) between molecules ________gas_________
33. What does temperature measure? _____average kinetic energy__________
34. What are attractive forces, intermolecular forces (in terms of states of matter…heating
curve/cooling curves of water) attractive forces are the forces that hold the molecules together in
a substance.
35. Describe the transfers of energy that occurs as liquid water freezes.
Heat from the water molecules will flow into the surrounding cold air. As the particles lose that KE,
they will slow down. Attractive forces will reform and cause a phase change from a liquid to a solid.
36. What happens to the kinetic energy, attractive forces (IFs), and energy of molecules as they move
from the liquid to gaseous state?
The overall energy of the substance will increase.
KE (which is measured as temperature) will remain constant during the phase change (plateau)
but will increase after the phase change in complete.
PE will increase during the phase change (plateau)
Attractive forces will be broken.
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Use the following phase change graph to answer the next few questions:
37. According to the graph, what is the freezing point of this substance?____72 degrees____
38. What is the melting point of this substance?___72 degrees________
39. What is the boiling point of this substance? ___140 degrees_________
40. What phase(s) is/are present a point A? _____solid____________________________
41. What phase(s) is/are present between points B and C?_______solid and liquid______________
42. What phase(s) is/are present between points D and E?______liquid and gas_______________
43. What is the difference between an endothermic and an exothermic reaction?
Endothermic – absorb energy
Exothermic- releases energy
44. Why does the temperature not change during a phase change?
Because the KE is breaking the attractive forces (IFs)
PHYSICS
1. What is the formula for calculating velocity? What is an appropriate unit to use for velocity?
V= Δd / t
Units=
m/s, km/hr, mph
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2. What is the difference between speed and velocity?
Velocity includes direction and must use displacement (vector), speed uses distance (scalar)
3. What is the formula for calculating acceleration? What is an appropriate unit to use for
acceleration?
A= Δv / t
Units= m/s2
Use the picture below to answer the next question:
4. You run from your house to the school. Next, you walk from the school to the mall. The entire trip
takes you 4.5 hours. What was your speed for the entire trip? What was your velocity for the
entire trip?
Distance = 2000 m
s= 2000m/4.5h = 444.4 m/hr
Displacement = -1000 m
v = -1000/4.5 = -222.2 m/hr
5. You walk 25 meters East down the hallway. Halfway to your class, you realize that you forgot
your book, so you walk 12 meters West back to your locker. What was your total distance
travelled? What was your total displacement?
Distance is 37 m
Displacement = 25m E – 12m W = 13 m E
6. What are three ways that you can change your velocity in a car?
Increase velocity, decrease velocity, or change direction
7. A runner covers the last straight stretch of a race in 4 s. During that time, he speeds up from 5 m/s
to 9 m/s. What is the runner’s acceleration in this part of the race?
(9-5)/4 = 1m/s2
8. Draw a displacement -time graph below for an object that is moving at a constant velocity. What
property of an object’s movement does the slope of this line represent?
Slope represents velocity
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9. Draw a velocity- time graph below for an object moving at a constant velocity. What property of
an object’s movement does the slope of this line represent?
Slope represents acceleration
10. Draw a position-time and velocity-time graph for an object accelerating.
Position-time
velocity-time
11. Draw a position-time and velocity-time graph for an object that is not moving.
Position-time
velocity-time (line should be on “x” axis)
12. What is the velocity of the object between 0-4 seconds?
(20-0)/(4-0) = 5 m/s
13. Between which time(s) is the object not moving? 4-6 seconds
Energy
1. What formula would you use to calculate:
a. Potential energy (gravitational potential energy)
Eg =mgh
b. Kinetic energy
Ek = 1/2mv2
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2. Use the diagram to the right. Label where the KE is highest and where the PE is highest.
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KE is greatest just before it hits the ground
PE is greatest at its highest point.
3. Define the following types of energy and give an example of each:
a. Mechanical Potential Energy- the energy an object has due to its position.
(ex- a ball being held up high has potential energy. It can be calculated using PE=mgh)
b. Mechanical Kinetic Energy-The energy an object possesses due to its movement
(ex- a ball dropping through the air. It can be calculated using KE=1/2 mv2)
4. Below is a graph of a roller coaster. Use the picture to answer the following questions.
a. Where is Kinetic Energy highest? 3
b. Where is KE lowest? 1
c. Where is Potential Energy highest? 1
d. Where is PE lowest? 3
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7. How are work and energy related?
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W = ΔEk
8. Calculate the kinetic energy of a 3900 kg car moving at 28 m/s.
½(3900)(28)2= 1528800J
9. A diver has 3400 J of gravitational potential energy after stepping up onto a platform that is 8.0 m
above the water. What is the diver's mass in kilograms?
3400=(m)(10)(8)
3400/80=m m=42.5kg
10. A man with a mass of 65 kg is standing on the edge of a table 2.5 m above the ground. What is
the man’s kinetic energy at the end of the jump, if he jumped off the table?
Eg=Ek
Eg=mgh
Eg = (65)(10)(2.5)= 1625J = Ek
11. A box (m = 48 kg) is pushed with a force of 151 N for a distance of 62 m.
a. How much work is done on the box?
W = F*d
W= 151(62) = 9362J
b. What is the change in energy of the box? (initial velocity = 0)
W = change in Ek
Ek = 9362J
12. You are planning a trip for winter break! How long will it take you to get there if you travel 500
km at an average pace of 60 km/hr?
S=d/t
60=500 / t
t= 8.3 hr.
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