Lab Skills Review

1. Lab Skills Review Run this PPT show to help you review for your test.

2. 1. The problem of an experiment is in the form of a ____. Question

3. 2. A ______ is an educated guess to the problem of the experiment. Hypothesis

4. 3. The ___________ states whether your hypothesis is correct or incorrect. conclusion

5. 4. What would make the results of an experiment carried out by a research team valid? The experiment was repeated and the same results were obtained each time.

6. 5. The _______ group does not contain the independent variable. control

7. 6. What is measured is known as the ______ variable. dependent

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

9. 8. 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.

10. 8. 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. b. Identify the independent and dependent variables. Independent: Growth hormone Dependent: Length of the seedling

11. 8. 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. 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.

12. 280 260 240 220 9. Identify the independent variable. Water temperature 10. Identify the dependent variable. Average water flea heart rate 200 180 160 140 120 100 80 60 40 20 5 10 15 20 25 30 35

13. 280 260 240 220 11. 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). 200 180 160 140 120 100 80 60 40 20 5 10 15 20 25 30 35

14. 280 260 240 220 12. What is the average flea heart rate at 15ºC? 118 beats/min 13. 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

15. 14. The results of one experiment carried out by a research team would be considered valid if a. the experiment had no control setupb. all the members of the research team came to the same conclusionc. the experiment had more than one variabled. the experiment was repeated and the same results were obtained each time

16. 15. Why do scientists make graphs of data from experiments?  a. to observe general trends and patterns in the data b. to make the observed data more accurate c. to prevent errors in measuring data d. to help change the original data tables

17. 16. Which is the dependent variable in Amelia's experiment? a. the number of bean plants in each group b. the amount of water given daily to each plant c. the height of each bean plant d. the amount of fertilizer given to each group of bean plants

18. 17. A new idea that is tested in a scientific experiment is known as a(an) a. theory b. hypothesis c. inference d. observation

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

20. 19. 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 a. control b. exercise c. rate of squeezing d. number of participants

21. 20. 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 a. control b. exercise c. rate of squeezing d. number of participants

22. 21. Why do scientists consider any hypothesis valuable? a. A hypothesis requires no further investigation. b. A hypothesis may lead to further investigation even if it is disproved by the experiment. c. A hypothesis requires no further investigation if it is proved by the experiment. d. A hypothesis can be used to explain a conclusion even if it is disproved by the experiment.

23. 22. What is the definition of volume? The amount of space an object takes up. 23. What is the name of the instrument used to measure the volume of a liquid? Graduated cylinder

24. 24. How is the volume of a liquid measured? Units? Use a graduated cylinder. mL or L 25. How is the volume of a regular solid measured? Units? length x width x height cm3

25. 26. Calculate volume. Show all work! 2cm 5cm 3cm • V = l x w x h • V = 3 x 2 x 5 • V = 30.0 cm3

26. 28. Measure the volume of the liquid to the left. 27. Measure the volume of the liquid to the right. 21mL 67mL

27. 30. Measure the volume of the liquid to the left. 29. Measure the volume of the liquid to the right. 2mL 49mL

28. 31. What is the volume of this toy dinosaur? 0.8mL (5.6mL – 4.8mL) 32. What is the name of this method? displacement

29. 33. What is the definition of mass? The amount of matter in an object. 34. What is the name of the instrument used to measure mass? triple beam balance 35. What are the units used to measure mass? grams

30. 36. Mass = 137.4 gm

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

32. 0 1 2 3 4 cm 38. What is the length of the object in millimeters? Centimeters? 8mm 0.8cm

33. 0 1 2 3 4 cm 39. What is the length of the object in centimeters? Millimeters? 2.8cm 28mm

34. 40. What is density? Mass per unit volume 41. How is the density of an object measured? Density = mass/volume

35. 42. What is the density of one cup of water? 1g/mL 43. What is the density of half a cup of water? 1g/mL

36. 44. What is the density of a 100gram object with a volume of 20 milliliters? 5g/ml 45. The object above was cut into three pieces. What is the density of one of those pieces? 5g/ml

37. 46. Explain why an object placed in a glass of water floats. The object has a density less than the density of water (1g/ml).

38. 47. Explain why an object placed in a glass of water sinks. The object has a density more than the density of water (1g/ml).

39. 48. Below is a list of the densities of different object. Will each one float or sink in water? a. 0.38 g/cm3 b. 1.7 g/cm3 c. 1.2 g/cm3 d. 0.99 g/cm3 e. 100 g/cm3 float sink sink float sink

40. CONVERSIONS KILO (k) HECTO (h) DECA (da) METER (m) DECI (d) CENTI (c) MILLI (m)

41. 49. Complete the following conversion: • 21hm = ____dm • 21. 0 0 0 = 21000dm

42. 50. Complete the following conversion: • 12cm = ____m • 12. = 0.12m

43. 51. Complete the following conversion: • 0.45m = ____ km • .45 0 0 0 = .00045km