Scientific Methods Grade 6 A practice investigation: the gummy bear challenge • Gummy bears were first made in Germany in 1920. You can use any other gelatin-covered jelly sweet, such as jelly babies, for this investigation. Teachers may like to substitute this investigation with one on another topic if they prefer. • You will use the seven steps to help you carry out your first MYP scientific investigation. STEP1: DESCRIBE THE RESEARCH QUESTION OR PROBLEM TO INVESTIGATE • First you need a question or a problem to investigate. This question or problem should be developed by you. Often, research questions come from observations we have made. Sometimes we carry out further research to find out more about the topic. • Put the gummy bear into a container with water, leave it overnight and observe what happens. • This observation should give you some ideas for a good research question. Research Questions • What are you thinking? How fast did the gummy bear grow? How much did it grow? What happens if you add other substances to the water? What happens if you increase the temperature? Do gummy bears of all colours grow in the same way? Here are some quite simple research questions. • Do gummy bears of all colours grow at the same speed? • How does the speed of growth change over time? • Does the growth change if you add other substances such as sugar to the water? • Does the temperature of the water affect how fast they grow? A more sophisticated research question could be as follows. • What factors control how much a gummy bear grows in water? Write your research question for your investigation. For this task, concentrate on the effect of adding sugar to the water. STEP 2: OUTLINE AND EXPLAIN A HYPOTHESIS (PREDICTION) • Scientists usually have an idea or theory about the results they are likely to obtain. This idea or theory is called a hypothesis. • A hypothesis is similar to a prediction. • Example: ‘My hypothesis is that if all colour gummy bears are added to the sugar solution then all colours will grow the same amount because the colour is a very small part of the gummy bear and is unlikely to have any effect.’ Write your hypothesis (prediction). STEP 3: DESCRIBE HOW TO CONTROL THE VARIABLES TO MAKE IT A FAIR TEST • The word variable is very important in science. It means the property of something involved in the experiment that can change. • There are three types of variables: Independent variable, Dependent variable and Constant variable. Independent variable • Variables that you change are called independent variables. For an investigation to be a fair test, only one variable may be changed at a time – all other variables must be kept the same. • For example: in this investigation you could decide to investigate the effect of changing the amount of sugar in the water. The amount of sugar would be the independent variable. List one independent variable to investigate, the dependent variable to measure and the control variables that you will keep the same. THE VARIABLES • Constant variables: The variables that are kept same are called the control variables. If you control these variables, you can say that it was a fair test. Example: For the experiment the type, size, and colour of gummy bear; the amount of water; the time; the temperature; and the size of the containers the same • Dependent variables: The variable that we observe in an experiment is called dependent variable. During an investigation, you will be measuring the outcome. In this investigation, this is the size of the gummy bear. This is called the dependent variable because it depends on the changes you are making to the independent variable. As you gain more experience with scientific investigations, you will state in your hypothesis the relationship between the independent and dependent variable. STEP 4: DESIGN THE METHOD WITH APPROPRIATE MATERIALS AND EQUIPMENT You should have a detailed plan for your investigation. Before you start, think about the following types of questions. • What equipment and materials do you need? • How will you set them up? • How will you make sure the method is safe? • What steps will you follow to carry out your investigation? • How will you change your independent variable? • What data will you collect? • How will you measure the change in size of the gummy bear? • Scientists need to share with other scientists exactly how they do their investigations, so a clear and logical plan is important. Your plan needs to be clear and easy to repeat so that other scientists can repeat your experiment. This is a very important aspect of how science works. • You should also state what data you will collect. In this case, you could simply say that you will carry out five different experiments: one with pure water and four with different numbers of teaspoons of sugar. • Where possible, scientists should repeat their results. Simply carrying out the experiments with one gummy bear each time would not be good science. Experiments can have errors and sometimes an unreliable result can be obtained. Repeating the experiment gives us more reliable results. In this case it is a good idea to use three or four gummy bears each time, or three or four different trials. Write your method for your experiments. A diagram is likely to help. STEP 5: COLLECT AND PRESENT THE DATA • During your investigation, carefully watch any changes that occur and take any necessary measurements. This is called experimental data. • Data can be collected in many ways, including measurements with suitable apparatus (for example, a ruler, photos or videos). The data is then recorded in a table. Sometimes it will be simply well-organised, written observations. • In your gummy bear investigation, you will need a table to record the original length of the gummy bear(s) and final length(s). Think about the headings your table will have. Don’t forget to include the units of any measurements you have made. Amount of sugar added (teaspoons) Initial length of gummy bear (cm) Final length of gum bear (cm) Difference in length (cm) COLLECT AND PRESENT THE DATA • If your results include numbers, then a good way to show the results is by drawing a graph such as a line graph, pie graph or column graph (bar chart). For this investigation, you could use a line graph. • You also need to draw a line of best fit, which is a straight line or curve that goes through as many points as possible, with an equal number of points above and below the line. Design your results table, carry out your experiments to collect the data, and then present your results using a graph STEP 6: Evaluation • DISCUSSES HOW WELL THE INVESTIGATION WORKED, THE ERRORS, POSSIBLE IMPROVEMENTS TO THE METHOD, FURTHER EXPERIMENTS THAT COULD BE CARRIED OUT AND WHETHER YOUR RESULTS AGREED WITH THE HYPOTHESIS • This is the reflective part of an investigation. Think about whether your investigation was successful – whether it actually tested the hypothesis.