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Lab Skills Review 7A 2013

Lab Skills Review 7A 2013. 1. The problem of an experiment is in the form of a ____. Question 2. A ______ is an educated guess to the problem of the experiment. Hypothesis. 3. 4.The ___________ states whether your hypothesis is correct or incorrect. Conclusion

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Lab Skills Review 7A 2013

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  1. Lab Skills Review 7A2013

  2. 1. The problem of an experiment is in the form of a ____. • Question 2. A ______ is an educated guess to the problem of the experiment. • Hypothesis

  3. 3.

  4. 4.The ___________ states whether your hypothesis is correct or incorrect. • Conclusion 5.What would make the results of an experiment carried out by a research team valid? • The experiment was repeated and the sample size was increased.

  5. 6.The _______ group does not contain the independent variable. • Control 7. What is measured is known as the ______ variable. • dependent

  6. 8. A new idea that is tested in a scientific experiment is known as the ________. hypothesis

  7. 9. To test the effect of hormones on plant growth, 6 potted plant seedlings of the same species were measured and then sprayed with a growth hormone. After 4 weeks of growth under ideal conditions, the plants were measured again. a. How would you set up the control group? • There should be another group with 6 plants that DO NOT receive water. b. Identify the independent and dependent variables. • Independent variable: Growth hormone • Dependent variable: Length of the seedling c. Give 2 factors that must be kept constant. • The amount of water each plant receives. • The temperature the plants were kept. • The species of plant used. • The amount of soil in each pot.

  8. 10. You studied the effect of the amount of fish food on the mass of goldfish. One tank of goldfish is fed the normal amount of food once a day. A second tank of goldfish was fed twice a day. A third tank of goldfish was fed three times a day. The fish's mass was measured three times a week. • State the problem. • What is the effect of the amount of fish food on the mass of goldfish? b. Give a possible hypothesis. • I think that feeding the goldfish three times a day will increase the mass of the goldfish the most. c. Identify the independent variable. • The amount of food d. Identify the control group. • The group of goldfish that were fed once a day.

  9. 10. You studied the effect of the amount of fish food on the mass of goldfish. One tank of goldfish is fed the normal amount of food once a day. A second tank of goldfish was fed twice a day. A third tank of goldfish was fed three times a day. The fish's mass was measured three times a week. e. Identify the dependent variable. • The mass of the goldfish. f. Identify 2 controls (factors that must remain constant). • Amount of fish in each group • Temperature of the water • Amount of light the fish are exposed to • The original mass of the fish

  10. 11. An experiment was done in which the heart rate of water fleas were measured after being placed in water at different temperatures. a. IV • temperature b. DV • Heart rate c. How would you label each axis on a line graph for this experiment? X axis = temp Y axis = heart rate d. What would be a proper title for this experiment? The effect of temperature on the heart rate of water fleas.

  11. 280 260 240 220 11. e. State the relationship between the average water flea heart rate and water temperature. As water temperature increases, the average water flea heart rate increases. • Direct Relationship 200 180 160 140 120 100 80 60 40 20 5 10 15 20 25 30 35

  12. 280 260 240 220 f. What is the average flea heart rate at 15ºC? • 118 beats/min g. What is the average flea heart rate at 30ºC? • 240 beats/min 200 180 160 140 120 100 80 60 40 20 5 10 15 20 25 30 35

  13. 12. Problem: Does an electric motor turn faster if you increase the voltage? a. IV • voltage b. DV • How fast the motor turns c. 1 constant • Same motor

  14. 13. Problem: Does heating a cup of water allow it to dissolve more sugar? • a. IV • temperature • b. DV • How much sugar dissolves • c. 2 constants • Type of sugar, how fast they stir it

  15. 14. Problem: Does fertilizer make a plant grow bigger? • a. IV • Amount of fertilizer • b. DV • growth • c. 2 constants • size of pot, same type of plant, amount of water, light

  16. 15. a. Identify the independent and dependent variables. • IV = amount of spring rainfall • DV = number of frogs in the pond b. State the relationship between the number of frogs in the pond. • Direct relationship (as the amount of spring rainfall increases, the number of frogs in the pond also increases) c. How many frogs are present when there is 15cm of spring rainfall? • 50 frogs

  17. 16. You want to test which size soccer is easier to juggle with your feet. You test the size 3, size 4, and size 5 ball. You count the number of seconds the ball stays in the air for each trial. You allow yourself to use both feet, knees and head to juggle the ball. a. Identify the independent variable. b. Identify the dependent variable. The size of the soccer balls. The number of seconds the ball stays in the air.

  18. 16. You want to test which size soccer is easier to juggle with your feet. You test the size 3, size 4, and size 5 ball. You count the number of seconds the ball stays in the air for each trial. You allow yourself to use both feet, knees and head to juggle the ball. c. What can be done to increase the validity of the experiment. Repeat the experiment. Use a larger sample size.

  19. 17. The results of one experiment carried out by a research team would be considered valid if 1. the experiment had no control setup2. all the members of the research team came to the same conclusion3. the experiment had more than one variable4. the experiment was repeated and the same results were obtained eachtime

  20. 18. Why do scientists make graphs of data from experiments?  to observe general trends and patterns in the data to make the observed data more accurate to prevent errors in measuring data to help change the original data tables

  21. 19. A new idea that is tested in a scientific experiment is known as a(an) theory hypothesis inference observation

  22. 20. Which statement about the use of independent variables in controlled experiments is correct? A different independent variable must be used each time an experiment is repeated. The independent variables must involve time. Only one independent variable is used for each experiment. The independent variables state the problem being tested.

  23. 21. An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin. In this investigation, the independent variable is the control exercise rate of squeezing number of participants

  24. 22. An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin. In this investigation, the dependent variable is the control exercise rate of squeezing number of participants

  25. 23. Which piece of equipment could be used to determine the mass of a frog? triple beam balance graduated cylinder beaker metric ruler

  26. 24. The basic unit of volume in the metric system is the kilogram gallon liter mass

  27. 25. Mass is best defined as the The amount of space an object takes up density of an object amount of matter in an object weight of an object

  28. 26. To measure the volume of an irregular solid, a student can use a triple beam balance a beaker displacement in a graduated cylinder a thermometer

  29. 27. The units for the volume of a solid is mL mm L cm3

  30. 28. The amount of space an object takes up is known as its mass density volume matter

  31. 29. What is the definition of mass? • The amount of matter in an object. 30. What is the name of the instrument used to measure mass? • triple beam balance 31. What are the units used to measure mass? • grams

  32. 32. Determine the cm length at each letter to the nearest tenth. • g = 9.7 cm • e = 10.3 cm • b = 11.3 cm • j = 11.7 cm • f = 12 cm • a = 12.5 cm • h= 12.95 cm

  33. 0 1 2 3 4 cm 33. What is the length of the object in millimeters? Centimeters? 8mm 0.8cm

  34. 0 1 2 3 4 cm 34. What is the length of the object in centimeters? 2.8cm

  35. 35. Mass = 332.7 g

  36. 36. Mass = 57.1 g

  37. 37. Mass = 345.7 g

  38. 38. Volume = ? Show all work 6.4 cm 8.4 cm 5.6 cm • V = L x W x H • V = 6.4 x 5.6 x 8.4 • V = 301.1 cm³

  39. 39. Volume = ? Show all work. 12.1 cm 5 cm 3.2 cm • V = L x W x H • V = 5 x 3.2 x 12.1 • V = 193.6 cm³

  40. 41. Measure the volume of the liquid to the left. 40. Measure the volume of the liquid to the right. 21mL 67mL

  41. 43. Measure the volume of the liquid to the left. 42. Measure the volume of the liquid to the right. 2mL 49mL

  42. 44. What is the volume of this toy dinosaur? 0.8mL (5.6mL – 4.8mL) 45. What is the name of this method? displacement

  43. 46. Volume of object = ? V = 20 –11.5 V = 8.5 mL V1 =11.5 mL V2 = 20 mL

  44. 47. Temperature: When using the Celsius scale: a. water freezes at 0°C b. water boils = 100°C c. human body temperature is 37°C

  45. 48. Convert the following measurements: 3 cm = _____ mm 15 cg = ____ mg 49 cm = ____ mm 103 cm = ____ mm 5 mm = _____ cm 19 mL = ____ cL 74 mm = ____ cm 158 mm = ____ cm

  46. c u d m k h d 3 cm = 30 mm 15 cg = 150 mg 49 cm = 490 mm 103 cm = 1,030 mm 5 mm = 0.5 cm 19 mL = 1.9 cL 74 mm = 7.4 cm 158 mm = 15.8 cm

  47. D = m = 9.2 g = 0.6 g/cm3 • v 14.3cm3 49. Frank has a paper clip. It has a mass of 9.2 g and a volume of 14.3cm3. What is its density? Show all work. 50. Frank also has an eraser. It has a mass of 3.3 g, and a volume of 1.5cm3. What is its density? Show all work. • D = m = 3.3 g = 2.2 g/cm3 • v 1.5cm3

  48. 51. a. Which layer has the highest density? • Green layer b. Which layer has the lowest density? • Yellow layer c. Imagine that the liquids have the following densities: 10g/cm3 3g/cm3 6g/cm3 5g/cm3 Which number would go with which layer? • Yellow = 3g/cm3. • Blue = 5g/cm3. • Red = 6g/cm3 • Green = 10g/cm3

  49. 52. D = mass = 50.00 g = volume 2.22 cm3 D = 22.5 g/cm3 Osmium is a very dense metal. a. What is its density in g/cm3 if 50.00 g of the metal occupies a volume of 2.22cm3? Show all work. b. Will this object float in water? Why or why not? No, it will not float because it’s density is greater than the density of water. It will sink. c. If you cut this object into 4 pieces what will be the density of each piece ? 22.5 g/cm3

  50. 53. Which diagram represents the liquid layers in the cylinder? (K) Karo syrup (1.4 g/mL) (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL) A B C K W V V W K W V K

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