safety review. chapter 1 the science of life lets play a game… am i alive? how can you tell?
TRANSCRIPT
Safety review
CHAPTER 1THE SCIENCE OF LIFE
Lets play a game…
Am I alive? How can you tell?
Characteristics of Life?
Organization Response to stimuli Homeostasis metabolism Growth and Development Reproduction Change through time
Organization
High degree of order between internal and external parts
Interactions with the living world Examples?
Response to stimuli
Ability to respond to changing environment
Homeostasis
ability to maintain a stable internal condition.
No matter the changes in environment.
Metabolism
Use of energy to power life processes
Growth and Development
Growth? increase in amount of living material Development? process ending in adulhood Ie. Frog
Reproduction
Production of Offspring Coded information is passed on to the
offspring Like Produces Like
Change through time
evolution
Science as a process
Scientific method
Organized approach to learn how the natural world works
Scientific method
1. Observation / question: 2. Hypothesis: tries to
answer question; proposed explanation
3. Prediction: guesses what will happen
4. Experiment: tests hypothesis
5. Collect and analyze data6. Supports or disputes
hypothesis
Scientific theory
When a set of confirmed hypotheses is confirmed to be true many times
Examples?
Tools of the trade
Microscopes1. Compound light microscope Uses light through a specimen Electron microscpes use a stream of
electrons to visualize a specimen2. Scanning (SEM) electron microscope 3-D surface view3. Transmission (TEM) electron microscope 2-D internal view
Compound Light Microscope
Scanning Electron Microscope
SEM
Transmission Electron Microscope
TEM
Light vs. Electron
SEM or TEM
SEM TEM
TEM SEM
SEM or TEM
SEM TEM
TEM SEM
More SEM
More SEM
More SEM
The Metric System
Common Metric Units
Length (meters) Mass (grams)1 meter (m) = 100 centimeters (cm)1 meter = 1000 millimeters (mm)1000 meters = 1 kilometer
1 kilogram (kg) = 1000 grams (g)1 gram = 1000 milligram (mg)1000 kilograms = 1 metric ton (t)
Volume (liters) Temperature (Celcius)1 liter (L) = 1000 milliliters (mL)1 liter = 1000 cubic centimeters (cm3)
0o Celsius (C) = freezing point of water100o C = boiling point of water
•System of measuremnt in science. •Based on multiples of ten = easy conversion
Ch 1 Vocab quiz next class
1. Biology2. Compound light
microscope3. Electron
microscope4. Gene 5. Hypothesis
1. Metabolism2. Metric
system3. Organization4. Scientific
method5. Theory
CH 2CHEMISTRY OF LIFE
Matter
Everything is made of matter (?) Has mass and occupies space
Elements and atoms
Element: substances that cannot be broken down into simpler substances
Atoms: smallest particle of an element that retains the properties of that element
Atomic structure
Nucleus makes up most of mass of an atom
Consists of protons (positive) and neutrons (no charge)
Number of protons = atomic number Number of protons + neutrons = mass number
Atomic structure
Electrons: negatively charged particles Balance out with positive charge of
protons Very small mass Move around the nucleus in orbitals
Isotopes
Atoms of same element have equal number of protons but not necessarily neutrons
Isotopes: atoms of the same element that have a different number of neutrons
Compounds
Made of atoms of two or more elements H2O CO2
CH4
A Covalent Bond occurs when atoms
share electrons
Covalent Bonds
Ionic Bonds
Example: Sodium Chloride
Oppositely charged atoms, attracted to each other
Note: they do not share electrons
Energy and Matter
Energy: ability to do work Many types of energy
Electrical Radiant (light) Thermal (heat) Chemical mechanical
Chemical reactions
One or more substances change to produce one or more different substances
Reactants: on the left side of the equation
Chemical reactions
One or more substances change to produce one or more different substances
Products: on the right side of equation
Activation energy
Energy needed to start a reaction
Catalysts reduce activation energy Example: enzymes
Water and solutions
Properties of water are necessary for life Many of water’s functions come from it’s
chemical structure Polarity: uneven distribution of charges Water is polar Polar nature allows water to dissolve
polar substances
Hydrogen bonding
Polar nature allows water to be attracted to one another
+ region of one moleculue attracted to the – region on another
Cohesion and adhesion
Cohesion: attractive force between molecules of a single substance Water attracted to water
Adhesion: attractive force between molecules of different substances Water attracted to other stuff
Quick cohesion and adhesion lab HOW MANY DROPS OF WATER CAN I PUT
ON LINCOLN’S HEAD? Get in lab groups. Send one member up to the front to get
a penny and a cup Count the number of drops that you can
put on the head of a penny
Temperature moderation
Water has a high heat capacity Water can absorb or release large
amounts of energy with only a slight change in temperature
This allows water to absorb heat during the summer to keep air cool w/o increasing the temp.
And at night, water cools and warms the air
Density
Is ice more or less dense than water?
Discuss with your partner and write your ideas down in your notes
Solutions
Solution: mixture of two or more substances
Solute: substance that dissolves in a solvent
Solvent: substance in which the solute is dissolved
Acids and bases
pH scale is used to measure acidity or alkalinity
Scale from 0 14 06.9: acid 7 neutral (water) 7.114: base Buffers: chemical substances that
neutralize small amounts of acids or base added to a solution They keep the pH from changing greatly