Turbo TAKS general science review Week 7 Lesson 1: Scientific Method Lesson 2: Lab Safety/ Equipment Lesson 3: Graphing Lesson 4: Predicting Trends in Data

Lesson 1: Scientific Method

Scientific Method – What is it? Observation Is the foundation of the scientific method Leads to a question about an event or characteristic Scientific Method is a step by step way to investigate this question

Scientific Method Steps Problem (Question) Hypothesis Procedure Data Conclusion

Scientific Method Hypothesis Is an “possible answer” to question that is formed from experience or research Has to be testable Usually an “If . . . then . . .” statement Will be rejected or accepted at the conclusion of an experiment

Terminology – Don’t get confused! Hypothesis: an trial answer to a scientific question Q: “How will studying affect my test score?” Hypo: “If I study for one hour, then my test score will be higher.” Prediction: states a possible outcome of an experiment designed to test the hypothesis “I will make an 85 on the test. Inference: a logical interpretation based on prior knowledge and experience (not an observation) “The sidewalk is wet so it must have rained.”

Scientific Method Procedure Procedures (experiments) must be repeatable 3 types of procedure variables: controlled variables - factors that kept constant and the same during the experiment independent variable – single factor you are changing or manipulating in the experiment; plotted on X axis dependent variable – the result or data you observe; plotted on the Y axis

Scientific Method Data & Conclusion Collect/ Analyze Data Report ALL results (expected and unexpected) Conclusion Tells what happened State patterns or trends in the data Explain why it happened that way

Lesson 2: Lab Safety & Equipment It’s better to be safe than sorry!

Be Safe – Protect Your Eyes and Skin ALWAYS WEAR GOGGLES and APRONS when working with chemicals, glass or heat Report any accident or injury to your teacher IMMEDIATELY! If you cannot notify the teacher because of your injury – have your lab partner tell the teacher!

Be Safe – Why do we do these? Never work alone in the lab. Tie back long hair, loose clothing & jewelry Wear proper clothing including closed toe shoes. Do not eat or drink in the lab. No playing in lab area. Water and electricity do not mix. Know where the safety equipment is located & how to use it! SHOWER, EYEWASH, FIREEXTINGUISHER, SINKS

Be Safe with CHEMICALS Read the MSDS sheets before working with chemicals. Dispose of chemicals and materials as directed by the teacher NEVER put chemicals back into the original or stock contains. This prevents contamination.

ALWAYS POUR ACID SLOWLY INTO WATER! “A & W Root Beer” is one way to remember it!

Be Safe with Gases or Fumes When working with fumes, work in the fume hood. Work in a well ventilated room. When smelling vapors, waft or fan them toward your nose.

Use Common Sense When using scalpels & knives, do not cut objects while holding them in your hand. Always cut away from your body. Use tongs or insulated/ thermal holders when handling heated objects. Hot glass looks like cold glass. Heat substances in test tubes with the open end pointing away from you and others.

The 4 C’s Caustic: capable of burning, destroying living tissue Carcinogen: any substance that could produce a cancer Corrosive: capable of “eating away” or corroding Combustible: capable of catching fire and burning

Hazard Ratings Red- Fire Yellow- Reactivity Blue - Health Risk White- Special Info Hazard Ranking 0-no danger 1-low danger 2-medium danger 3-high danger 4-extremely deadly

Explosive Flammable Toxic Oxidizer

Lab Equipment

Flasks, Beakers & Test Tubes Not used for measuring volume Give only approximate amounts Used to hold substances and contain reactions

Volume Volume is measured with graduated cylinders, pipets and burets Read the bottom of the meniscus Longest, thinnest, most lines = most accurate

Volume of an Irregular Object If you have an object with a weird shape, use the water displacement method to find its volume: Fill a graduated cylinder ½ full of water Record the volume of water Drop in the irregular object Record the new volume of water Subtract to find the how much the volume of water changed – this is the volume of the object

More Equipment Time is measured with a stop watch Mortar & Pestle is used to crush chemicals Masses are measured with a beam balance or electronic balance Distances and lengths are found with a ruler Temperature is measured with a thermometer pH is found with a pH meter or litmus or pH paper Petri Dishes hold specimens & grow bacteria Innoculation Loop is a wire used to transfer microorganisms

Lesson 3: Graphing

Line Graph Line graphs are used when you have numerical data for the independent variable and numerical data for the dependent variable Very useful in predicting patterns or trends

Is minimum wage increasing or decreasing over time? State the pattern

Bar Graphs Give overall numerical data for several groups There are no dependent and independent variables. Bar graphs can be drawn horizontally or vertically. This type of graph is very useful for comparing two or more groups

Which factory has the least defects per 1000 cars?

Which country has the most immigrants?

Pie Graph (Circle graph) Useful for displaying percentages or proportions. A circle is divided according to the proportion of counts in each category. Not suitable for data sets with a very large number of categories (use for 6 or less categories)

According to the survey, do the students want to wear uniforms According to the survey, do the students want to wear uniforms? (student survey)

Music Preference for Young Adults What is the least preferred type of music?

Volume of Irregular Object (Rock) Water Displacement Method Fill a graduated cylinder about half way Read the meniscus Slide the object into the slanted graduated cylinder (so you don’t splash out any water) Read the new meniscus Subtract the 2 volumes to find the volume of the rock

Lesson 4: Predicting Trends in Data It costs extra money to include pictures, diagrams & graphs on tests. They are included on tests for a reason. When a test question has pictures, diagrams or graphs - LOOK AT THEM ! When you are drawing a conclusion or predicting a trend in the data, you must base your answer on the data given in the table, graph or diagram. This means that they have given you the answer!

Do NOT rely on anything except what is given to you. If an answer choice is about something not mentioned or goes against the given data, it is NOT the right answer.

HINTS for Prediction Questions 1. Look at every table, graph or diagram before you ever read the question. 2. Read the title and axis labels, they are usually in the correct answer. Make sure you know what the data is describing! 3. Now, read the question and all the answers. 4. Mark out the answers do not relate to the graph or go against the data provided.

Let’s try: According to the data in the table, about how far can a spring be expected to stretch when a force of 3.92 N is applied? A 10.5 cm B 13.6 cm C 14.0 cm D 17.3 cm Force (N) L (cm) 0.98 3.5 1.96 7.0 2.94 10.5

Answer: C 14.0 cm Reasoning: Each time the force goes up .98N - - - the spring is stretched 3.5 cm. 10.5 + 3.5 = 14.0

The diagram illustrates how some characteristics of the horse have changed over time. Along with the difference in size, what is another anatomical difference between the modern horse and its ancestors? A The structure of the tooth has been adapted for eating meat. B The size of the molars has decreased. C The length of the forefoot has decreased. D The number of toes has decreased.

Answer: D # of toes decreased Reasoning: On left side of table, time goes from the bottom ( a long time ago) to the top (recent time). Looking that the pictures, you can mark off answers A, B, and C