Life Science Ch. 1.1 What is Science?

Types of Science Science is described as an organized way of studying things and finding answers to questions. There are many types of scientists: life science studies living things, zoologists study only animals, botanists study plants.

Critical Thinking and Solving Problems Scientists have to use critical thinking. Critical thinking is a way you use skills to solve problems. Solving problems are what drives a scientists. They use the scientific method to help them solve problems.

State the Problem The first thing a scientist has to do is to figure out what problem they want to find the answer to. Example: What color of light will a plant grow the best under?

Gather Information Laboratory observations and experiments are ways to collect information. Fieldwork is another way to collect information. Fieldwork includes observations or experiments that are done outside of the lab. Example: We watch some plants that are growing in different colors of light.

Form a hypothesis A hypothesis is a prediction that can be tested. It is not a random guess, it is an educated guess. It is always an if…then statement. Example: After observing plants and learning about chlorophyll (a pigment in plants) my hypothesis would be: If plants are exposed to red light, then the plant will have more growth than any other type of light.

Perform an Experiment Scientists need to use controlled conditions. A control is the standard that the experiment is compared to. A variable is something in an experiment that can change. An experiment should only have one variable. That is important so we know what causes the change.

Perform an Experiment Continued Example: I would set up my experiment, my control would be a plant in normal light, I would then have plants growing under blue, green, and red light. I need to make sure that they are the same type of plant, same soil, and watered exactly the same. They should also be exposed to the light the same amount of time.

Analyze Date During an experiment the scientist should collect data. After the experiment is over the data should be looked at to see trends. Usually graphs or tables are used to help analyze data.

Analyze Data Continued Example: After several days of measuring my plants I make a table and a graph to compare the growth of each plant.

Draw Conclusions A conclusion is a logical answer to a question based on data and observation. After a scientist draws a conclusion they need to decide if their hypothesis was correct or not. If it is not correct (rejected) the scientist needs to re-experiment. Ex – I look at the data collected and see that in fact the plant that grew with red light grew the most. I do not need to do another experiment.

Report Results It is extremely important to report the results. The results and the experiment needs to be reported so others can test the findings. Ex. – I would publish my information in a journal or on a website so other scientists can repeat my experiment to see if they get the same results.

Theories A scientific theory is an explanation of things or events based on scientific knowledge. A theory will have a lot of evidence to support it. It is not a guess. Theories can change if new evidence is found. Example of theories: cell theory, theory of evolution

Scientific Laws A scientific law is a statement about how things work in nature that seems to be true all the time. They are less likely to change than a theory. Laws tell what happens but not necessarily why it happens. Examples: Newton’s law of gravity, laws of heredity

Scientific Units Scientists use the International System of Units (SI system) for measurement. In the United States we use customary units, but most countries and all scientists use the SI system.

Length The base unit for length is meter. We then use prefixes to indicate smaller or larger sizes. Millimeter (mm) Centimeter (cm) Kilometer (km)

Volume Liter (l) – base unit Milliliter (ml)

Mass Gram (g) – base unit Milligram (mg) Kilogram (kg)