Science Skills Practice Identifying variables Key terms: Variables Control variables Independent variable Dependant variable all the factors that could have an effect on the investigation the most important variables that should be considered, they usually need to be controlled (kept constant) to have fair test the variable you will be changing and testing this is the variable you measure that depends on the independent variable. TASK 1 Using 2 different colours, highlight the independent and the dependent variables in the 9 investigation aims listed below. Write or draw the colour of each variable in the spaces below: Colour of the independent variable __________________ Colour of the dependent variable __________________ An investigation: 1. into how the temperature of water affects the time a potato takes to cook 2. to find out how current size affects a bulbs brightness 3. to show how the number of bulbs in a circuit affects the current size 4. to find out how the height a ball bounces is affected by how far it drops 5. to see if plastic, metal or wooden cups keep drinks warm the longest 6. to show how heart rate is affected by the number of step ups you do 7. to see if a car’s colour makes it go faster 8. to see if light brightness makes plants grow quicker 9. to find out if iron rusts faster in different concentrations of salty water Scientific Method TASK 2 Rebecca wants to do an investigation to show how heart rate is affected by the number of step ups you do. (a) Write an appropriate aim for Rebecca’s experiment. ………………………………………………………………………………………………… ………………………………………………………………………………………………… (b) Write a testable, valid hypothesis for this experiment. ………………………………………………………………………………………………… ………………………………………………………………………………………………… (c) What is the independent variable for this experiment? ………………………………………………………………………………………………… (d) What is the dependent variable for this experiment? ………………………………………………………………………………………………… (e) List three variable that should be controlled in this experiment. ………………………………………………………………………………………………… (f) Write a method in past tense as a list of logically progressing steps which have sufficient detail so that everyone reading that method would be able to take the same set of actions. ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… Graphing TASK 3 Two animals (X and Y) live in a zoo. The zookeepers measured the air temperature and the body temperature of each animal at various times. The first measurements were taken just before sunrise. The last measurement was taken at 3 pm. Present the data in the table in the form of a line graph. For fast finishers… 1. The graph at the right represents the typical day of a teenager. Answer these questions: a. What percent of the day is spent watching TV? b. How many hours are spent sleeping? c. What activity takes up the least amount of time? d. What activity takes up a quarter of the day? e. What two activities take up 50% of the day? f. What two activities take up 25% of the day? 2. Answer these questions about the graph at the right: a. How many sets of data are represented? b. On approximately what calendar date does the graph begin? c. In what month does the graph reach its highest point? 3. Answer these questions about the graph at the right: a. What is the dependent variable on this graph? b. Does the price per bushel always increase with demand? c. What is the demand when the price is 5$ per bushel? 4. The bar graph at right represents the declared majors of freshman enrolling at a university. Answer the following questions: a. What is the total freshman enrollment of the college? b. What percent of the students are majoring in physics? c. How many students are majoring in economics? d. How many more students major in poly sci than in psych? 5. Answer these questions about the graph at the right: a. How much rain fell in Mar of 1989? b. How much more rain fell in Feb of 1990 than in Feb of 1989? c. Which year had the most rainfall?
