Science TAKS Tutorials: Science TAKS Tutorials Objective 1 1A, 2A-2C
Safety and Measurement Your Mission Today: Your Mission Today Watch slides review. The words from the slides are already in your notes. Use these notes as you answer the questions.
When the examples are finished you will have 16 minutes to work on the questions.
When time is up, the answers to the questions will appear.
4. Review the information and the questions the TAKS Science Test on Thursday, July 12th.
Why do we have to practice safety in Science Laboratories? : Why do we have to practice safety in Science Laboratories? To protect yourself
Safety Equipment: Safety Equipment Fire Extinguisher
Shower – Eyewash Rinse a full
15 minutes! aim toward the base of the flame Fire Safety: Fire Safety Notify teacher
smother the flame
with fire blanket Protect YOURSELF!!!: Protect YOURSELF!!! Safety equipment is to protect YOU!
Keep goggles and apron on the ENTIRE time you are in the lab and while ANYONE is still performing an experiment. Goggles Apron Slide7: Sharp objects: cut away from yourself and others.
Toxic Chemicals Waft to gently smell a scent. If chemical is toxic or caustic, use a fume hood.
Broken glass: notify teacher and dispose of broken pieces on specific glass disposal containers Toxic Chemicals: Fume Hood
protects from toxic
fumes or vapors
-health risk- Toxic Chemicals When one waft causes harm use a Slide9: Biohazard
Potentially Harmful Can be a form of bacteria, human blood, human wastes Corrosive
A harmful chemical reaction that can erode metal, wood, or human flesh. (acids, rusts, bases..) When in doubt check the Material Safety Data Sheets for EXACT information on the Fire, health, reactivity and radioactivity RISK! Slide10: This symbol is used to warn an individual of potential dangers. 100 Safety symbol 4 1 2 0 Red-Fire Hazard
Blue- Health Risk
Propane 0 – no risk
2 - med risk
4 – high risk Slide11: 300 A product that has the tendency to catch on fire easily or is combustible. Flammable Slide12: 200 When you are toxic, you are considered to be- Poisonous Slide13: 500 When there is a chance of danger, harm or loss. Hazard Slide14: 600 Something that causes irritation to one’s skin, eyes, nasal passage or airways. Irritant Slide15: 700 To eat or wear away gradually by chemical reaction. Corrode Slide16: 800 Using your senses to learn about an object or an event. Observe Slide17: 900 To remove or throw away. Dispose Slide18: 900 To easily ignite, catch fire, smolder or burn. Examples are wood or paper. Combustible Slide19: A variable is something that changes. What are some factors that might change when growing plants? Soil Light Water Temperature Container size Slide20: Dependent Variable: changes as a result
of the independent variable. It is the one
that you measure or observe during the experiment. (mass of tomatoes,
temperature, height of plants, etc.) Experimental Design includes: Independent Variable: the variable that you change during the experiment. (type of fertilizer) Constants: The factors that are kept constant and not allowed to change ( soil, pot size, temperature, light, water) Slide21: The Experimental Group is that which is being tested with the independent variable (type of fertilizer)
Each test group has only ONE factor that is
different from the other test groups: the independent variable. The number of times the experiment is repeated, trials, determines the accuracy of the results. With more trials the experiment is more valid. At least 3 trials should be made. Slide22: A control should be added to show that the experiment has resulted in some kind of change.
The control group is the group or standard to which everything is compared.
If comparing the results of tomato plants with various fertilizers, one plant would be grown without fertilizer. This is the control group. Slide23: Use both the dependent variable and
independent variable in the same
sentence to write the hypothesis.
Think about what the relationship is between the independent and dependent variables.
In the example with tomato plants, the type of fertilizer is the independent variable. The mass of tomatoes is the dependent variable. Forming the Hypothesis If Fertilizer X is used to grow tomato plants, then the mass of tomatoes will be greater than with other types of fertilizers. Hypothesis Conclusion: Conclusion A conclusion describes the purpose, explanations and major findings
What should be considered in a conclusion?
Is there a measurable change?
Does it reflect the supporting data?
Can it explain the findings? A conclusion must be based
on the experimental data!
Microscope: Microscope Brings the specimen into focus for observation A lens with a
10X or greater Holds the objectives that may vary in magnification 4X, 10X, 40X, 100X Adjust amount
of light that reaches
specimen 2006 TAKS Question!! LAB EQUIPMENT 1: LAB EQUIPMENT 1 Beaker Test Tube Rack Test Tube Thermometer Flask Graduated Cylinder LAB EQUIPMENT 2: LAB EQUIPMENT 2 BURETTE WATCH GLASS SCALPEL METER STICK TRIPLE BEAM BALANCE LAB EQUIPMENT 3: LAB EQUIPMENT 3 BUNSON BURNER DROPPER HOT PLATE Slide29: If you are massing a powder, use weighing paper on the tray and subtract the mass of the paper from the mass of the paper and powder together. An electronic balance is also used to measure mass.
The precision of this balance is to the nearest hundredth 0.00 g Measuring Mass Slide30: 0+10+7=17.0g To measure mass, use a triple beam balance. This measures to the nearest tenth in grams.
What is the mass of the rocks? Slide31: To measure volume of a liquid in ml, use a graduated cylinder, a burette, or a pipette. The smaller the units of measure, the more precise the measurement will be. Graduated cylinder Pipettes and bulbs Measuring Volume Beakers and flasks are used for holding liquids. They do not make precise measurements. Burette Flasks What is the volume reading for the solution in graduated cylinder?: What is the volume reading for the solution in graduated cylinder?
Read from the bottom of the meniscus …
? 21.4 mL Slide33: A burette measures the amount of liquid that is dripped out. You must subtract the initial volume from the final volume to determine the total. Remember to read the bottom of the meniscus. 48.5 ml final volume
- 0.8 ml initial volume
What is the volume dripped from this burette? Slide34: You will have a ruler on the side of your formula sheet. USE IT if you are asked to measure distance on a map or a length. You must measure accurately and precisely. The wrong answer choices will test to see if you do. Use a spring scale to measure weight in Newtons. Slide35: Answer = 52.5 mL Measure from the bottom of the meniscus ? Practice #1 Practice # 2: Practice # 2 Answer = 100+ mL Measure the amount of
gas in the container Practice # 3: Practice # 3 Answer = 137.4 g Add up the numbers… 100 30 7.4 Practice # 4 : Practice # 4 Answer 21.0°C Answer 4.5°C Slide39: You have
16 minutes to work on the questions. Slide40: 4 5 6 7 8 9 10 11 12 13 14 15 16
Slide41: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Slide42: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Slide43: 0 1 2 3 4 5 6 7 8 9 10 11 12 13
Slide44: 0 1 2 3 4 5 6 7 8 9 10 11 12
Slide45: 0 1 2 3 4 5 6 7 8 9 10 11 Slide46: 0 1 2 3 4 5 6 7 8 9 10 Slide47: 0 1 2 3 4 5 6 7 8 9 Slide48: 0 1 2 3 4 5 6 7 8 Slide49: 0 1 2 3 4 5 6 7 Slide50: 0 1 2 3 4 5 6 Slide51: 0 1 2 3 4 5 Slide52: 0 1 2 3 4 Slide53: 0 1 2 3 Slide54: 0 1 2 Slide55: 01 Slide56: 0 Slide57: Get Ready
Check v What is the mass of the object being measured in the figure?: What is the mass of the object being measured in the figure? The correct answer is B. Look carefully at the increments on each beam before you find your final answer. Notice that this balance has precision to 0.00 grams. 1 39.100 g B. 100.39 g C. 11.39 g D. 139.0 g 100
0.01 100 + 0 + 0 + 0.39 = 100.39 grams Slide59: Only 10% of the electrical energy operating a light bulb is changed into visible light. Which instrument helps identify the energy change occurring to most of the remaining 90%? A. Triple-Beam Balance (mass)
B. Thermometer (temperature)
C. Magnifying Glass (lens)
D. Prism (splits white light) The correct answer is B. A light bulb uses energy to heat the filament. When you touch the light bulb it can be hot. This is energy that is lost to the environment as heat. Heat is energy. You would use a thermometer to measure the heat that is lost. 2 Slide60: Ten seeds were planted in each of five pots containing 700 g of “Sure Potting Soil”. Each day for 40 days, spring water is given weekly as follows: Pot 1, 50 mL; Pot 2, 100 mL; Pot 3, 150 mL; Pot 4, 200 mL; Pot 5, 250 mL. The recommended amount of water to use is 150 mL. The student decided to measure the height of each plant at the end of the experiment. Identify the dependent variable in this experiment.
A. height C. Pot and height
B. height and water D. Water The correct answer is A. A dependent changes as a result of the independent variable. The dependent variable the measurable change in an experiment. In this one it is the plant height. 3 Slide61: An advertisement claims that a certain truck has the most powerful engine in its class. If the engine has more power, which of the following can the truck’s engine do, compared to every other engine in its class.
A. Produce fewer emissions
B. Operates more efficiently
C. Perform work faster
D. Accelerate longer The correct answer is C. The best conclusion that you can make from the information given is that the truck is more powerful. 4 Slide62:
A medical researcher hypothesizes that a newly developed medication can reduce high blood pressure. Which of these would most likely be the dependent variable in a study involving this medication?
A. The number of participants in the study
B. The ages of people treated for high blood
pressure with other medications
C. The blood pressure of the participants in the study
D. The number of people treated for high blood pressure
with other medications The correct answer is C. A dependent variable changes as a result of the independent variable. The dependent variable is what shows a measurable change in an experiment. In this experiment is blood pressure. 5 Slide63: The label shown on the right contains
information about some harmful
effects of acetone. A group of students plans to use acetone to rinse out a glass container. A second group of students is working at the same lab table.
Which of the following lab procedures should the second group of students avoid?
A. Heating water with an open flame
B. Pouring hydrochloric acid into a beaker
C. Filtering precipitates from a liquid solution
D. Collecting oxygen from plants in a test tube The correct answer is A. The question is about safety. The safety symbol clearly shows that this is a high fire risk. In words it states that Acetone (used in nail polish remover) is volatile (evaporates easily releasing vapors) and has is flammable as a liquid and as a vapor. 6 Conclusion: Hearing aids are an effective way to treat hearing loss: Conclusion: Hearing aids are an effective way to treat hearing loss A study was conducted to test the effectiveness hearing aids. People with different types of hearing loss were included in the study. Which question would help in determining whether the conclusion above is valid?
A. What was the average age of the people in the study?
B. What was the most common occupation of people in the study?
C. How many people were included in the study?
D. How many people in the study had vision problems? The correct answer is C. A conclusion must use information from the experiment. A hearing aid was being tested for effectiveness. The larger the size of the group being tested the more accurate the results. 7 Potential Hazards of Petroleum Naphtha, Hexane, Toluene, and AcetoneMay cause eye, skin, nose, and throat irritation. Inhaling or swallowing vapors may be harmful or fatal. Vapor may ignite explosively. Known to cause birth defects: Potential Hazards of Petroleum Naphtha, Hexane, Toluene, and Acetone May cause eye, skin, nose, and throat irritation. Inhaling or swallowing vapors may be harmful or fatal. Vapor may ignite explosively. Known to cause birth defects The ingredients described on are used to make a bonding agent. The most important safety precaution to take when applying this bonding agent is to —
A. dry it with a small flame
B. cover the work areas with newspaper
C. work in a well ventilated area
D. wear a lab coat The correct answer is C. This can harm you. Protect yourself! Use a vent hood for harmful vapors. 8 Slide66: A student needs to measure exactly
42.5 mL of an acid. Which of the following pieces of laboratory equipment would it be best for her to use?
A. 10-mL graduated cylinder
B. 50-mL beaker
C. 50-mL graduated cylinder
D. 250-mL flask The correct answer is C. Choose the most precise piece of equipment that comes the closest to the total volume of liquid being measured. 9 Slide67: What is the mass of the object being measured in the figure? The correct answer is A. Look carefully at the increments on each beam before you find your final answer. Notice that this balance has precision to 0.00 grams. 10 0 + 40 + 7 + 0.52 = 47.52 grams 100
0.01 Slide68: Which question cannot be answered by experimentation using a scientific approach?
A. Does hot water freeze faster than cold water?
B. Will wearing a copper bracelet reduce arthritis symptoms?
C. Do roses smell better than carnations?
D. Will popcorn kernels soaked in water produce a greater volume of popped corn than dry kernels? 11 The correct answer is C. The experiment would be biased due to the results would be based on an opinion, not a fact. The choice of a scent is a personal one. Some animals will choose a carnation over a rose and others will choose the rose over the carnation. Slide69: When a 10% hydrochloric acid solution is heated in an open test tube, the test tube should always be pointed_
A. so bubbles are visible
B. toward a ventilated area
C. at a 180° angle from the flame
D. away from nearby people 12 The correct answer is D. As the liquid in the test tube gets hot and steam could be released. This could irritate your mucus membranes and eyes. Protect yourself and others when working in the laboratory. Slide70:
The reason for wafting or fanning a small amount of chemical vapors toward the nose as a means to detect odors in a test tube is to —
A. avoid experimental error from excessive loss of mass
of reactants or products
B. avoid splashing chemicals into the face of any person
C. protect the respiratory tract against potentially harmful vapors
D. determine the relative strength of the odor before smelling directly 13 The correct answer is C. Wafting allows only a few molecules of the sent to enter your nose, but it will still allow you to get a scent of the odor. Safety is to protect yourself and others from harm. Slide71: Reactions that produce toxic gases should be performed in a
A. laboratory fume hood
B. beaker with a watch glass on top
C. well-ventilated area of the lab
D. warm, airtight drying oven 14 The correct answer is A. Toxic gases are considered to be poisonous. A fume hood has a strong fan that pulls the toxic gases out of the work area. Slide72: The surface of liquids in a glass cylinder is always curved. This curved surface is called a meniscus. When reading a volume of a liquid, read the bottom of the meniscus. What is the most precise volume of the liquid shown in the figure?
A. 19.4 mL C. 19.57 mL
B. 19.42 mL D. 20.58 mL 15 The correct answer is B. Read the labels first. Determine the value of each tick number between 19-20. Count to the nearest 0.1 then add a decimal place for the uncertainty that is above the tick mark 0.42. Measure from the bottom of the meniscus. Slide73: The illustration shows volume levels of a liquid in a graduated cylinder before and after a sample was removed. According to this information, what was the volume of the sample to the nearest milliliter? A. 38.0 ml
B. 48.0 ml
C. 10.0 ml
D. 9.0 ml The correct answer is D. The initial volume was 47mL and the final volume was 38 mL. The volume removed= 9mL. Measure from the bottom of the meniscus. 16 Slide74: Which of the following pieces of equipment would be most appropriate for measuring the volume of a marble? 17 The correct answer is B. A graduated cylinder measures volume. B. Graduated cylinder
-milliliters ml A. Digital Balance
–grams) C. Metric Ruler
-meters m -centimeters cm D . Beaker
Mixing – heating
Not accurate for
measuring Slide75: Which lab setup would be appropriate to use in heating 100 mL of water to the boiling point?
A. A 10 mL test tube held above a Bunsen burner
B. A 200 mL beaker placed on a hot plate
C. A thermal coil inside a 100 mL cylinder
D. A sealed 300 mL flask in a warm-water bath The correct answer is B. Beakers are used to heat liquids or combine liquids. The 200 mL beaker will allow room for expansion. 18 Slide76: Which of the following procedures should be used in finding the mass of crystals?
A Pour the crystals into a graduated cylinder
B Put the crystals on the outer part of the
balance pan for massing
C Pour crystals into a small container and use a
D Use weighing paper on the pan of a triple
beam balance The correct answer is D. To find the mass of loose chemicals, place them with weigh paper on a triple beam or electronic balance. 19 Slide77: Which of the following will allow measurement of a liquid’s volume with the greatest precision?
A 50 mL cylinder graduated in 1 mL increments
B 100 mL cylinder graduated in 0.5 mL increments
C 100 mL cylinder graduated in 1 mL increments
D 200 mL cylinder graduated in 5 mL increments The correct answer is B. The smaller the increments allow for greater precision. 20