What is Science? Chapter 1

Definition: Science is a way of using evidence (data/observations) to understand the natural world Science that follows a process, which allows for questions to be answered using results (data/observations) Errors in the experiment are minimal (controlled experiment) List 4 Characteristics: Testable hypothesis, clear procedure, easily identified variables, hypothesis answers research question or explains problem What is the goal (purpose) of science? Investigate and understand the natural world; explain events, and use those explanations to make predictions

A question. A problem. Some event or phenomena that needs an explanation.

Scientific Method (list and explain the steps) 1. Identify problem 2. Write a research question 3. Write a hypothesis that ANSWERS the question 4. Explain the procedure to test the hypothesis 5. Display and explain results, write observations 6. Write conclusions of observation and results

Designing an experiment Ask a question Form a hypothesis (prediction & reason) If…then…because 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 Validity- a step in the procedure to ensure good data Reliability- repeating steps in the experiment, or repeating the entire experiment. Record and Analyze Results Qualitative Data: Descriptive Quantiative Data: Numbers Draw a conclusion

Problem: My car won’t start. Design an experiment to figure out how I can discover why my car won’t start. Write a question, hypothesis, and a brief procedure What will the results show us? What is our conclusion?

Science, Observation, Data, Inference, Hypothesis, Quantitative Data, Qualitative Data, Theory Control variable, Manipulated variable, Responding variable, Controlled experiment

Biology is the study of living organisms Living things share eight characteristics

1. Living things are made up of cells. Unicellular One cell Multicellular Many cells Humans have over 85 different types of cells!

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. DNA: deoxyribonucleic acid

4. Living things grow and develop. differentiation – cells look different and perform different functions. Nerve cells, muscle cells, skin cells, liver cells

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

7. Living things maintain a stable internal environment. Homeostasis – the ability to keep internal conditions constant.

8. Living things, taken as a group, change over time. Evolution – change over time.

Things scientists have to be able to do include… 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”

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. A testable statement about how nature operates Many theories are so well established that it is very unlikely that any new evidence will alter them significantly, but they can be modified and improved Examples: Heliocentric Theory (Earth revolves around the sun) Atomic Theory (all matter composed of atoms) Cell Theory (all living things made of cells) Evolutionary Theory (organisms change over time)

A device we use to magnify images we can’t see with our eyes Light – magnify by focusing visible light Samples are placed on slides to be observed Electron – magnify by focusing beams of electrons. Require a vacuum to operate so they can only look at preserved specimens. Scanning electron microscope (SEM) – electrons scan the surface. 3-D images Transmission electron microscope –electrons shine through a specimen. 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?

Carry your microscope carefully, with two hands Place slides on the stage of your microscope and secure it with the microscope clips Look through the eyepiece at your slide Always start on LOW power Use the focus knobs to adjust the image you see Low power = big focus knob High power = small focus knob When making a drawing from your microscope…. Lots of detail! Include title and magnification Use pencil and shade in your drawing