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The goal of science: is to investigate and understand the natural
world, to explain events and use those explanations to make predictions.
1. Observation – gather info in an orderly way.
2. Collect data Quantitative – numbers Qualitative – descriptive
3. Data allows us to make inferences – interpreting our data using our prior knowledge.
4. Hypothesis – An explanation for a set of observations. “educated guess”
Designing an experiment Ask a question Form a hypothesis (prediction & reason) Set up a controlled experiment
manipulated – variable that is changed responding – variable that reacts to the
change controlled – variables (need 2) that stay the
same Record and Analyze Results Draw a conclusion Publish/Repeat experiment
Validity – Something you do in the experimental procedure to get accurate data.
Reliability – Repeating an experiment
Constraint – a problem you encounter while designing a solution to a scenario.
Limitation – an explanation of your solution to the scenario -
When evidence from numerous investigations builds up a hypothesis may become so well supported that we call it a theory.
Theory – WELL TESTED explanation that unifies or explains a broad range of observations.
Example: Why are marsupials (kangaroo) only
found in Australia? Both the theory of plate tectonics and the theory of evolution work together to answer this question.
Characteristics of Living Things
1. Living things are made up of cells.
Animal Cells – Cheek cells
Plant cells - Elodea
2. Living things reproduce.
Sexual – 2 different cells unite
Asexual – single parent, cell divides in half (bacteria)
3. Living things are based on a universal genetic code. D.N.A.
4. Living things grow and develop.
differentiation – where cells look different and perform different functions.
Nerve cell
Skin cell
5.Living things obtain and use materials and energy.
Metabolism – the building up or breaking down materials to carry out life processes.
6. Living things respond to their environment. Stimulus – a signal to which an organism
responds.Examples: Temperature, Light
Low blood glucose in animals = hunger
7. Living things maintain a stable internal environment.
Homeostasis – the ability to keep internal conditions constant.
Metric system – based on the number 10.
100 cm = 1 meter 10 cm =____ meter 12 mm = ____ centimeters
Which one doesn’t belong?
Light – magnify by focusing visible light Electron – magnify by focusing beams of
electrons. Require a vacuum to operate so they can only look at preserved specimens.
2 Types
1. SEM – Scanning (external detail)
2. TEM – Transmission (internal detail)
A-D Scanning Electron Microscope E Transmission Electron Microscope
F Light Microscope
Can you identify which type of microscope took pictures A-F?
Laboratory Techniques Cell culture – take a single cell,
add a nutrient solution and grow more cells….
Cell fractionation – this technique is used when you want to study one part of a cell so you have to separate the cell parts.
Steps blend cells add liquid put in centrifuge tube and spin cell parts will separate by density