Biology chapter 1

It is important for scientists to

*Observe *Collect Information *Test Ideas *Make Predictions *Share their findings with other scientists who can disagree with or confirm their findings

Steps for Investigation: Scientific Method for doing experiments

1. ASK A QUESTION- (about something you observe) 2. STATE YOUR HYPOTHESIS- (a possible answer to the question)- "If..Then..Because" statement which is testable 3. IDENTIFY AND CONTROL VARIABLES- a variable is something that can change in a test: you control the independent variable. A dependent variable changes when an independent variable changes. For a fair test choose just one variable to change- keep all of the other variables the same. Be sure to have a control group (the standard against which change is measured)- the experimental group is the same except that one factor has been changed. 4. MAKE A PLAN- to test you hypothesis- gather materials, make a list, document the steps in your test 5. COLLECT, RECORD, AND INTERPRET OBSERVATIONS- make diagrams, charts or graphs- keep good records of what you do and what you find out. 6. STATE YOUR CONCLUSION- an inference you make based in your data- does your data support your hypothesis- communicate your findings 7. DO REPEATED TRIALS- repeat the experiment a few times exactly the same way- the results should be similar for the conclusion to be valid- others should be able to repeat the experiment and get similar results

Scientific investigations begin with

1. An observation 2. then scientists ask a question about the observation 3. next they collect data to answer their question (they collect data in an experiment)

Types of investigations that scientists use are

1. Controlled Experiments 2. Models 3. Surveys 4. Sampling *These help scientists test hypotheses

How do scientist ensure that their work is valid?

1. They share their results with others. 2. Their experiment must be replicable (repeatable) 3. Their conclusions must be based on evidence (set of observations that make you believe something is true.

inference

A conclusion based on observations. Observations are facts.

evidence

A set of observations that make you believe that something is true.

control group

A standard against which change is measured. In an experiment, the experimental group is the same as the control group EXCEPT that one factor has been changed. The control group is the group for which nothing has been changed

hypothesis

A statement of what you think will happen during an investigation; a prediction.

Draw and Defend Conclusions

After analyzing the information that has been collected- scientists draw conclusions about what they have discovered- they defend their conclusions by using the observations they made during their investigation

Why is it important that Scientists communicate and share their results with others?

Because one way for Scientists to ensure that their work is valid is to share their results with others.

Why is communication important in Science?

Because one way for Scientists to ensure that their work is valid is to share their results with others. Scientists must describe their procedures and honestly report their findings-(conclusions/inferences based on evidence). Each of their investigations must be repeatable by other scientists, so they must describe exactly what they did in an experiment and how they did it.

Why do scientist make hypothesis before beginning scientific investigations?

Because, if a hypothesis is proven to be correct, then it is generally accepted by Science. Scientists must form their hypothesis from research and experience so they can closely predict what they think the outcome of their experiment will be. This helps them to solve the problem that they defined at the beginning of their experiment.

Conclusions

Conclusions-(inferences) that scientists draw about their experiment. Conclusions must be based on evidence-(observations and data that make you believe something is true). Scientist use their observations to draw a conclusion. They summarize what they have learned by analyzing their observations.

Scientists use their observations to

Draw conclusions. When scientists draw a conclusion, they summarize what they have learned by analyzing their observations

What happens if evidence shows results that are unexpected?

If the evidence does not support a scientist hypothesis, then this does not mean that the experiment was not useful, it means that unexpected findings can lead to a new understanding of a scientific concept. This causes scientists to experiment further.

Example Of Hypothesis

If..Then..Because A STATEMENT If air pollution increases, then the tree population will decrease, because polluted air kills the trees.

Median

In the middle= half of the data are lower than the median and half are higher

data

Information from which a conclusion can be drawn or a prediction can be made. Data are facts.

Models

Models are objects or ideas that represent other things. Models are often used to study things that are very large, have many parts or are difficult to observe directly so models of them are made. Models show how something is constructed or how it works.

Observations and Data

Observations and Data are FACTS. Scientists use observations and data to draw a conclusion. Observations lead to the recording of data. Scientists ask questions about their observations and then collect data to answer their questions, then they have their evidence. Opinions are not facts, they are simply beliefs or value judgements.

Different conclusions can be drawn from the same set of data

Other scientists may question the methods another scientist used and different conclusions can be drawn. So, evidence from the investigation must be must be researched and reviewed.

Tools

Scientist use many different kinds of tools to collect data. They must use precision and accuracy when measuring, taking temperatures,.... Tools help you gather information and analyze data and tools can help you find information collected by others. Examples of tools are: microscopes, scales, thermometers, stops watch, calculator, graduated cylinder, spring scale, meterstick........

Sampling

Scientists also use sampling to collect data- where they examine just a few random individuals from a large population and then generalize their results to all the people of the large population.

Tables and Graphs

Scientists can organize data in a table, once the information has been organized into a table then it may be displayed in a graph, such as a bar graph. Graphs help scientists to see mathematical relationships in their data. The information in the table and the graph is the same, it is just displayed in different ways.

Why is it important for scientists to repeat the investigations of other scientists?

So that they can see if the results are the same, and so that they can ask questions about the experiment and point out problems. Although some variation in results is acceptable, the results from different scientists should be similar- if the results are not similar and consistent then the experiment must be done again.

variable

Something that can change in a test.

observation

Something you find out about objects, events, or living things by using your senses.

procedures

Step-by-step instructions for completing a task.

Surveys

Surveys can be questionnaires that are given to a number of people who's answers are recorded and then analyzed.

precision

The ability to consistently repeat a measurement.

accuracy

The ability to make a measurement that is as close to the actual value as possible.

Mean

The average= add the data together then divide by the number of data

Range

The difference between the largest value and the smallest value in the data

experiment

The use of scientific methods to test your hypothesis.

Scientists can help people answer questions, solve problems, and form new ideas through

The use of scientific processes

Mode

The value in the data that occurs most often

Scientists look at values when they interpret data

These values help scientist determine the quality and usefulness of data so that they can decide if they have enough information to draw a conclusion or if they should collect more data. *Mean- the average= add the data together then divide by the number of data *Median- in the middle= half of the data are lower than the median and half are higher *Mode- the value in the data that occurs most often *Range- the difference between the largest value and the smallest value in the data Once the scientists analyze at all the values and interpret the data then they are ready to make an inference or conclusion based on their observations of the data values

How do scientist define a problem

They do research, then they can make a prediction; Hypothesis

Interpreting the Data

When scientist interpret data, they look at the information they have collected by using tools with precision and accuracy to safely observe, measure and estimate. Then they try to find patterns in the data to help them make predictions

Organize Data

When scientists use tools to make observation, they collect data. Data must be organized to be useful. Data can be organized in tables, graphs, charts and graphics. When data is organized scientists can see patterns and results more easily so that they can then draw their conclusions.

When you design an experiment

You must thoroughly explain and document your procedures exactly so that others can repeat your experiment and get similar results.

Make sure to follow all safety rules when doing experiments.

safety rules: wear safety goggles, never smell or taste anything, listen to instructions, no loose clothing, tie back hair.