SCIENTIFIC METHOD LAB EQUIPMENT, PROCEDURES, AND SAFETY Inquiry and Problem Solving Processes and Skills

Why do we study Science? Investigate and understand the world Explain events in the natural world Use the explanations to make useful predictions

The Methods of Biology Scientific Method – common steps that scientists use to gather information and answer questions.

Scientific Method 1. Problem – observation or question State the problem – What do you want to find out? Research the problem – What do we already know about it?

Scientific Method 2. Hypothesis – testable statement that answers the question Also called an “educated guess” based on experiences

Scientific Method 3. Design the Experiment – Develop a plan to test the hypothesis by determining: dependent and independent variables constants (or controls) type(s) of data to gather

Scientific Method 4. Conduct the experiment Set up Perform Record data Perform calculations and/or organize data into charts, graphs, or diagrams

Scientific Method 5. Conclusion – reports results Based on the data, was the hypothesis correct? If data was not correct, can you develop a new hypothesis to test?

Scientific Method 6. Theory – accepted idea that is true based on the evidence from repeated experiments that supports it

Match the steps to the question. Each step may be used more than once or not at all. 1. What is the first step of the scientific method. 2. After stating the problem, what is the next step? 3. Deciding what kind of data to gather takes place during which step? 4. Which step comes after conducting the experiment? 5. When are variables and controls determined? 6. Which step gives a possible explanation to a problem that can then be tested? 7. If an idea can be proven over and over again, it can proceed to which step? 8. Data is gathered during which step? 9. During which step is the hypothesis proved or disproved? A. conclusion B. forming a hypothesis C. theory D. conducting an experiment E. designing the experiment F. stating the problem

Performing Scientific Experiments Collect the Data When a biologist conducts an experiment, he or she investigates a phenomenon in a controlled setting to test a hypothesis. Biologists use controlled experiments to obtain data – Quantitative or Qualitative – that support or do not support a hypothesis

Performing Scientific Experiments Quantitative Data – numbers or amounts Measured data – length, mass, pH, temperature Qualitative data – descriptive data Color, odor, taste, feel

Variables A control group is used for comparison. Every experiment needs a test group and a control group. The experimental group gets the treatment of the experiment. Nothing is done to the control group. Constants are kept the same for BOTH groups.

Variables The independent variable is the treatment and is tried on the test group. The dependent variable would be counted or measured after the treatment is given. Dependent variable depends on independent variable. What depends on what?

Conducting an Experiment Freddy wants to determine which fertilizer A, B, or C, will cause tomato plants to grow the fastest. His hypothesis is that the tomato plants fertilized with C will grow the fastest because it has the most phosphorus.

Plant growth What kind of data should Freddy collect in his experiment?

Measure and record height What will he measure to determine growth?

Freddy decides to measure in inches every two days for three weeks. Now that he knows he’s going to measure height, he needs to answer the following questions in order to design his experiment. What will be his control group? How many experimental groups will he have? How many plants should he put in each group?

Group that gets same amount of light and water but NO fertilizer Control group?

Groups that get the different types of fertilizer – A, B, C Experimental groups?

Freddy decides to plant 5 tomato plants in each group for a total of 20 plants

Soil, sunlight, amount of water, number of plants What are important constants in Freddy’s experiment?

Plant height depends on the fertilizer Can you determine the independent and dependent variables in Freddy’s experiment? Remember what depends on what?

Saving Sam Activity Sam is stuck on a boat, and how he got there is not important, but Sam can't swim and the boat is capsized. To get to shore, Sam needs to retrieve a life jacket from underneath the boat so that he can float to shore. You and your partner's job is to save Sam but retrieving the life jacket from under the boat and putting it on Sam. Unfortunately, the only tools you can use to accomplish this task are paperclips. You cannot touch Sam, the boat, or the life preserver with your bare hands. Use the Scientific Method to Save Sam!!

Saving Sam Analyze and Conclude the experiment:  Discuss (tell me what you think) about the difficulty of the task, what other strategies you and your partner worked on before your succeeded, and what you think the critical steps were for solving the problem  Although this is working backwards, and not how scientists normally work, please develop a hypothesis for this lab. (remember that a hypothesis is an ‘if-then’ statement: If I do this, then this will happen)

Saving Sam – Scientific Method Problem: How can you and your partner save Sam using only paper clips? You may not touch Sam, the boat, or the live preserver directly with your hands. Materials: Gummy worm, Gummy “Life Saver” preserver, plastic cup and a paper clip per person Procedures:  Work with your partner(s) & “Save Sam”  Follow the rules: Remember NO HANDS  Develop a data section that includes diagrams of how you saved Sam and a detailed protocol describing the diagrams

Conducting an Experiment Activity Each group will have a scenario. Given each scenario, design an experiment to answer the experimental question. Identify a control group, dependent and independent variables and possible outcomes or what type of data would be gathered. You will not actually be performing these experiments. Turn in your design on paper – each group has one paper.

Graphing

Pie Graph Pie graphs are used to show percentages, compare parts of the whole.

Bar Graph Bar graphs are used when one of the variables is not a number.

Line Graph Line graphs are used when both variables are numbers.

Dependent and Independent Variables on Graphs

Trends in Line Graphs You can normally look at the data on a graph and determine the trend. There are 5 types of trends:  Upward  Downward  Peaking  Unstable  Unchanging Data

Upward Trend The dependent element increases as the independent element increases.

Downward Trend The dependent element decreases as the independent element increases.

Peaking Trend The dependent element increases to a point and then begins to decrease as the independent element increases.

Unstable Trend The dependent element increases and decreases several times as the independent element increases.

Unchanging Data Trend The dependent element does not change (stays constant) as the independent element increases.

Lab Equipment

Metric Ruler Used to measure length

Thermometer An instrument for determining temperature

Graduated Cylinder: Designed to make accurate volume measurements which are always read from the bottom of the curve (meniscus) The smaller the cylinder, the more precise measurement Get eye level to read

Beaker Used to hold measure and transport liquids Measures volume

Bunsen Burner To heat substances

Test Tube: Made of special glass; used to carry and heat chemicals Test tube clamp is used to carry test tube Hold at 45° angle away from you and others to heat

Test Tube Rack Designed to hold test tubes

Medicine Dropper: Transports or measures out small amounts of a liquid

Pipette Used to transport liquids (usually small drops)

Petri Dish Flat disk with a cover used primarily to grow bacteria

Triple Beam Balance An instrument used for measuring mass

Microscope Used to view very small objects at a magnification of 40 to 100 times

Cover Slip To flatten the object being viewed and to keep the lens clean

Hand Lens Magnifies small objects up to 10 times

Dissecting Tools: Dissecting pins: to stabilize the organism Dissecting scissors: to cut the organism Dissecting tray: To hold the organism

Forceps: Similar to tweezers; used to grab small objects

Funnel: Used when pouring things from one container to another to avoid spills

Probe A pointed object used to examine organisms (used during dissection)

Safety Goggles To protect your eyes

Scalpel A small blade used to cut tissues

Erlenmeyer Flask Commonly used for storing & mixing liquids

Florence Flask Commonly used for storing & mixing liquids

LAB Safety

The most important Lab Safety Rule…….. Always follow directions

Goggles Goggles should always be worn when chemicals are used, heated, or mixed.

Chemical Rules: If you get chemicals in your eyes or on your skin, wash for 15 minutes. Never EVER point a test tube or bottle that you are heating toward yourself or anyone else. Wave or waffle scents toward you, do not EVER smell directly over a chemical!

Chemical Rules: If you need to smell a chemical, hold it 6 inches away from your nose and wave the fumes toward your nose. NEVER smell chemicals directly!!!!

Cleanliness: Your lab area should always be clean when you start a lab and when you finish a lab. If a toxic substance was used, follow proper disposal directions given by your teacher.

Just say NO: Horseplay is NEVER allowed in the lab. If you are caught horse-playing you will be kicked out of the lab. Food, drinks or gum is NOT allowed to be out during a lab.

Dress Code: Always tie long hair back Closed-toe shoes only No loose clothing; roll baggy sleeves up tight If it dangles, it’s dangerous!!!

Fire: If there is a fire in the room, notify the teacher IMMEDIATELY. If the fire is on you, stop, drop, and roll.

Always remember: Its better to be safe than sorry Tell the teacher if any accident occurs

Safety Symbols

Clothing Protection

Biological

Corrosive

Disposal Safety

Electrical Safety

Extreme Temperatures

Fumes

Sharp Object Safety

Toxic

Irritant

Flammable

Eye Safety

Animal Safety

Microscope

Ocular or Eyepiece Arm Stage

Revolving Nosepiece Coarse Focus Objective Lens Fine Focus Body Tube

Base Stage Clips Diaphragm Mirror or Light Source

The kind of microscope we use at Pearl High school is the Compound Light Microscope.

This type of microscope can view cell organelles but it can not view DNA.

Proper use of the microscope:  Always carry microscope with one hand on the arm and the other hand on the base.

When preparing a slide, always put the cover slip on at a 45 degree angle.

If there are air bubbles, gently tap cover slip with a pencil eraser.

The purpose of the cover slip is to prevent the lens from touching whatever you are viewing.

Any object viewed under a microscope will appear upside down and backwards.

The objective contains the magnification powers of the microscope. They are attached to the nosepiece which revolves so you can go from low to high power easily.

To determine magnification of the microscope, multiply the objective times the ocular.

 40 power 10 power  Magnification =?

You will get the widest field of view with the least magnification. Which has the widest field of view? Ocular 10X Objective 20X Ocular 10X Objective 40X