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Class 9 · Science
→If a controlled variable gradually changes during an experiment what type of error may appear in the results?
Class 9 · Science
→Distance between a plant and lamp is changed to alter light intensity. How should the independent variable be recorded more accurately?
Class 9 · Science
→In which experiment is the dependent variable operationally defined most clearly?
Class 9 · Science
→A student tests the effect of soil moisture on earthworm number. If all samples are collected only after rainfall which external variable remains poorly controlled?
Class 9 · Science
→In an experiment plant growth is measured at five different fertilizer amounts. What is the purpose of using three plants at each amount?
Class 9 · Science
→Which statement correctly distinguishes a controlled variable from a control group?
Class 9 · Science
→What is the main advantage of recording the initial resting pulse rate while testing the effect of exercise duration on pulse rate?
Class 9 · Science
→A student changes both water temperature and container size while measuring evaporation rate. What is the main flaw in this design?
Class 9 · Science
→What difficulty may occur if the chosen values of the independent variable differ only slightly?
Class 9 · Science
→When investigating the effect of temperature on metal length what measurement is more appropriate if initial lengths are unequal?
Class 9 · Science
→Why may percentage of germinated seeds be a better dependent variable than the number germinated in an experiment on salinity?
Class 9 · Science
→Reaction rate was measured at four temperatures but a catalyst was also added in the highest-temperature trial. Why is the conclusion doubtful?
Class 9 · Science
→A student defines the independent variable as the value obtained at the end of an experiment. What is wrong with this statement?
Class 9 · Science
→Why is it necessary to give equal amounts of water to all plants when comparing growth in different soils?
Class 9 · Science
→In which situation would time be the independent variable?
Class 9 · Science
→A plant's height is measured daily but sometimes from the soil surface and sometimes from the bottom of the pot. What type of problem is this?
Class 9 · Science
→A student tests whether stirring speed affects dissolving time. Which experiment is the fairest?
Class 9 · Science
→An experiment tests the effect of sound intensity on concentration. Participants are given questions of different difficulty. Which variable was not controlled?
Class 9 · Science
→While testing the effect of surface type on friction the force needed to pull an object is measured. What does this force represent?
Class 9 · Science
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