Download What are atoms? Notes - Riverdale Middle School

1st 9 weeks
Unit 1 Nature of Science Notes
page 11
8/18/16 Thursday
What is Science?
Science is a way of learning about the natural world that provides possible explanations
to questions.
Scientists ask questions about the natural world (why, how or when) and try to answer those
questions using evidence they gather. This process is called scientific inquiry.
What are the 3 branches of science?
Physical science
Earth Science
Life Science
Observation
Example: Brandon is wearing a red shirt.
Inference
Example: Mario coughed, he might have a cold.
Observation – Tree branches are on the front lawn.
Inference – The tree branches were probably blown out of the trees by the wind.
Description is a summary of observations.
Ex: Mr. Bennett measures 6’4”.
Explanation is an interpretation of observations.
Ex. The grass is very high as a result of all the rain last week.
Scientific law vs. Scientific Theory
page 13
8/22/16 Monday
Model is a representation of an object or an event that is used as a tool for understanding the
natural world.
Example: map, globe, atom model, & solar system model
How do scientists communicate? Publish reports in journals, books, & internet attend meetings
& give presentations.
Scientific theory is a possible explanation for repeatedly observed patterns in nature
supported by observations and results from many investigations.
Example: Einstein’s theory of relativity
Scientific law is a rule that describes a pattern in nature but does not try to explain why
something happens.
Example: newton’s laws of Motion
Scientific law vs. Scientific theory
Both are based on repeated observation and can be rejected or modified.
A scientific law states that an event will occur. A law stands true until an observation is made
that does not follow the law.
A scientific theory is an explanation of why or how an event occurred. A theory will never
become a law.
What do scientists do?
Page 17
Thursday & Friday 8/25/16 & 8/26/16
Scientific method is a series of steps that scientists use when performing an experiment.
Hypothesis is an explanation that can be tested with a scientific investigation.
Data are information that is gathered during an investigation.
Data can be recorded in the form of descriptions, tables, charts, graphs or drawings.
How do scientists analyze data? They organize the data as a chart such as a table, a graph, a
diagram, a map, or a group of pictures.
They look for patterns in the chart that show connections between important variables in the
hypothesis being tested.
How do scientists draw conclusions?
A conclusion is a statement about whether or not the hypothesis is valid based on the
data collected.
Decide if the data clearly support or do not support the hypothesis.
If the results are not clear, rethink how the hypothesis was tested and make a new plan, this
would modify the hypothesis.
Record the results to share with others.
Tools of the Scientist
Page 21
Tuesday & Wednesday 9/6/16 & 9/7/16
What are types of data?
There are two general types of data:
Quantitative data descriptions of the natural world using numbers.
Ex: length, width, height, mass & weight
Qualitative data are descriptions of the natural world using words.
Ex: colors, smells, textures & tastes
How do scientists collect data? Tools
Rulers and meterstickes – measure length
Graduated Cylinders – volume – amount of space an object takes up.
Thermometers – measure temperature
Balances & Scales – measure mass
Mass – amount of material in an object
Computers and the internet – organize, analyze, display data, do research & share scientific
information.
Graphs are used to organize & summarize data as well as show relationships between data in
a visual way.
Ex: bar graphs, line graphs, & circle graphs
Tables are used to display information in rows and columns so it is easier to read and
understand.
How do scientist communicate data?
Page 23
Tuesday & Wednesday 9/6/16 & 9/7/16
Mean, Median, Mode, & Range
– Mean is the sum of the numbers in a set of data divided by the number of entries in the
set.
• A list of five test scores include:
60, 67, 73, 63 and 67. What is the mean?
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a) Mean: (60 + 67 + 73 + 63 + 67)
5
• 330
5
= 66
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– Median is the middle number in a data set when the data are arranged in numerical
order.
A list of five test scores include:
60, 67, 73, 63 and 67. What is the median?
60, 63, 67, 67, 73
67
– Mode is the number that appears most often.
A list of five test scores include:
60, 67, 73, 63 and 67. What is the mode?
67
– Range is the difference between the highest and lowest values in a data set.
A list of five test scores include:
60, 67, 73, 63 and 67. What is the range?
73 – 60
= 13
2nd 9 weeks
Solid, Liquid, Gas
Page 41
Tuesday/Wednesday 10/18 & 10/19
“Fixed
Vibrating
Position”
“Able to
slide past
one
another”
“Fast and
far apart”
Unit 2 lesson 3 outline
Thursday/Friday 10/20 & 10/21
page 42
Changes of State Diagram
Thursday/Friday 10/20 & 10/21
Page 43
How does heat affect matter? Notes
page 45
Thursday/Friday 11/3 & 11/4
• Increasing temperature (particles are moving faster) energy is being absorbed
– Solid to liquid – melting
– Liquid to gas – vaporization
• Boiling – vaporization at the boiling point below the surface Ex:
boiling water
• Evaporation – vaporization temperature below boiling point occurs at
the surface Ex: puddle
– Solid to gas – sublimation (skips a state) Ex: dry ice (solid carbon dioxide
CO2)
• Decreasing temperature (particles are moving slower) energy is being released
– Gas to liquid – condensation
– Liquid to solid – freezing
Boiling point – when the temperature is increasing it’s the temperature at which a
liquid becomes a gas
Condensing point – when the temperature is decreasing it’s the temperature at which
a gas becomes a liquid
Melting point – when the temperature is increasing it’s the temperature at which a
solid becomes a liquid
Freezing point – when the temperature is decreasing it’s the temperature at which a
liquid becomes a solid
– The boiling point & condensing point of water is the same 1000C.
– The melting point & freezing point of water is the same 00C.
What are atoms? Notes
page 55
Thursday/Friday 11/17 & 11/18
• Where are the electrons, neutrons, and protons located in an atom?
•
The protons and neutrons are in the nucleus. The electrons are all located within
the electron cloud.
• What are the charges of the parts of the atom?
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Electrons are negatively charged, protons are positively charged, and neutrons
are neutral or no charge.
• How does the mass of a neutron compare to the mass of a proton?
•
The mass of a proton and neutron are about equal at 1 a.m.u. (atomic mass unit)
• How does the mass of an electron compare to the mass of a proton or a neutron?
•
The mass of an electron is 1/1,840 times smaller than a proton or a neutron.
Atoms have energy levels where electrons are found in the electron cloud.
Each energy level can hold a certain number of electrons:
1st energy level = 2 electrons (closest to the nucleus)
When full, electrons begin to fill the second level.
2nd energy level = 8 electrons
When full, electrons go to the next-higher level.
3rd energy level = 18 electrons
• The last occupied energy level might or might not be completely filled.
• Electrons in the outermost level are called valence electrons.
– These outermost electrons are involved in chemical bonding.
What refers to an area around an atomic nucleus where an electron is most likely to be?
Electron cloud
Most of the atom is empty space. The nucleus in the center of the atom has most of the mass.
What are elements? Notes
page 57
Monday 11/28
Elements - a pure substance that cannot be broken down into a simpler substance.
– Ex. The human body is made mostly of water (H2O). Water is not an element
because it can be broken into simpler substances of Hydrogen (H) and Oxygen (O).
Hydrogen and oxygen are elements.
• An element is identified by the number of protons contained in each of its atoms.
– Ex. Oxygen atoms contain 8 protons, Atomic # 8
– Nitrogen atoms contain 7 protons, Atomic # 7
• Atomic number the number of protons in an atom of an element.
• Isotopes are atoms of the same element that have different numbers of neutrons.
• The mass number of an atom is the sum of the number of protons and neutrons in an
atom.
Mass number = number of protons + number of neutrons
To get the mass number off the periodic table take the average atomic mass and round to
the nearest 100th
Example:
Sodium’s atomic mass is 22.99 which round to 23. The mass number is
23. The atomic number of Sodium is 11. The number of protons is 11. Mass number =
protons + neutrons. 23 = 11 + ____ The number of neutrons for Sodium is 12.
What is the periodic table? Notes
page 42
Monday 11/28
• Periodic table - a chart that shows the elements in order of increasing atomic number.
• Elements on the periodic table are organized in periods (rows) and groups (columns)
according to their physical and chemical properties.
Electrical resistance is a measure of how difficult it is for an electric
charge to flow through an object.
Conductors (like metals) have low electrical resistance and allow
electricity to flow easily because their atoms’ valence electrons can
easily move from atom to atom.
Ex. Electric wires are usually made of copper.
• A good insulator has high electrical resistance.
• Atoms of an insulator hold electrons tightly and prevent
electricity from moving easily through the material.
Ex. Electrical wiring covered with plastic