Reporting on a Science Investigation

Reporting on a Science Investigation How to write a lab report at Iona College

Parts of a Lab Report • Introduction: Problem/Question & Hypothesis • Procedure: Aim, Equipment and Method • Data or Results: Usually as a table and graph • Analysis – what are the trends from the results • Conclusion - relates back to hypothesis • Discussion or evaluation of the investigation

Example: A Pendulum Investigation • If you change the length of the string, will it affect how fast the pendulum swings?

The title tells the reader what the lab is about. Be specific Science titles tend to be long! “My Lab Report” “Science Investigation” “Pendulum Lab” “Investigating Pendulum Swings and String Length” Create an informative title

Investigation starts with a problem to be solved or a question a clear statement of your research question Eg. “If you change the length of the string, will it change how fast the pendulum swings?” Hypothesis Sets conditions and predicts Use “That if ….then…” Predicts results Is testable* Eg. “That if the length of the string is longer, then, the pendulum will …………...………………..…..” Introduction

“Problem: If you change the length of the string on a pendulum, will it change how fast the pendulum swings?” Fast could mean: more swings per 10 seconds. Or quicker time taken to complete 10 swings. Problem: In this lab we are investigating the relationship between the length of a pendulum string and the rate of the swings. We are studying pendulums in order to develop our investigation skills. State the Problem - discuss

Writing a hypothesis Need to relate to the question • “I think the pendulum will be faster.” • “In a smaller distance the pendulum will travel back and forth faster and shorter.” • “The short string will not continue to swing back and forth for as long as the long swing.” • “The pendulum will swing back and forth. The long string many change fast.”

Writing a hypothesis “I think the longer the pendulum string is, the more time it will take to make swings.” “That the pendulum will swing slower on a longer string” “That if the string is longer then the pendulum will take more time to complete 10 swings.”

Aim Relates to question Starts with “To investigate ……..” Equipment a list of equipment or materials you used how many, what size Method a drawing of how the equipment was set up explains the steps you took to investigate your question - describes time period, location, details, etc. It’s replicable - someone else could repeat it exactly write it in past tense Procedure

Equipment & Materials • A metal washer • String • Ruler • Timing device Be specific about what you actually used

Equipment & Materials • One 3cm metal washer • Cotton string one metre long: to provide • 20cm, 30cm, 40cm, 50cm, 60cm lengths • A metre measuring stick • Stopwatch • Retort stand

Experimental Method • 1. Construct a “pendulum system” out of the string and a metal washer. See diagram. • 2. Test how long it takes to complete 10 “full swings” of the pendulum. • 3. Make a table to show the results of your pendulum tests. • 4. Use a piece of graph paper to make a line graph. Don’t just copy instructions – use past tense and be precise – see next page.

Experimental Method • We set up a pendulum as in the diagram. We started with a pendulum with a 20 cm length of string. • Each time we started the pendulum we held the string out horizontally and dropping the washer. • We recorded the time (in seconds) to complete 10 full swings. (We counted each back and forth as one full swing) • We repeated these steps to complete 3 trials and then calculated the average time taken to complete 10 swings. We recorded our data on a results table. • We repeated steps 2 to 4 for lengths of string of 30cm, 40cm , 50cm and 60cm. We processed our data as a line graph. (continued)

Show special equipment or a method “Here is a diagram of how we set up the pendulum.”

Results or Data • Result or Data table • Be organized with headings with labels and units • Write numbers neatly and clearly • Repeat the tests - do at least 3 trials • Graphs - x and y axis with clear labels - show the units - include a title

Poorly organized data

Unlabeled Data

Clear data Need to include units at top of table columns

Process data for analysis • summary of the data in words • Highs, lows, trends or any patterns you notice • Include UNITS on all measurements. • cm, m, sec, hrs, kg, g, • explain any mathematics that you used • Added, Subtracted, Calculated averages, • Equations • Choose appropriate graph type • Line, bar, pie chart • uncertainties – accuracy of your measurements

What problems do you see?

Example of a graph

What problems do you see?

Conclusion • Restate your hypothesis for this lab • Decide… “The data ________________ my hypothesis.” (supports, does not support) • Tell the conclusions you reached about your research question • Generalize:What is the general principle involved?

Writing a Conclusion “Our hypothesis was right.” • Not enough to say only this. • Restate the hypothesis. • Tell if it is supported or not.

Writing a Conclusion “Our hypothesis for this lab was that if the string was longer then the pendulum would swing more slowly than the shorter string. The data supports our hypothesis. In general, the longer the string, the slower the pendulum swings ”

What if your hypothesis is NOT supported? “My hypothesis was wrong!” “Throw out the whole experiment!!” Don’t throw out your results! “The data did not support my hypothesis but I learned that …. which means that… Next I would like to try…. “

Discussion of the results • Refer to specific data. Refer to the graph. - “The graph shows….” • Use language that describes change. • “The time taken to complete 10 swings decreased when …...” • “As string length increased, the time taken ……..” • “The graph shows that the time taken to complete 10 full swings _________as the string length ________.”

Evaluation of the investigation • What problems did you have? • Think about the strengths and weaknesses of your method. How could you improve this if you did it again? • Is this investigation a fair test? • Think about the variables you controlled or changed • Think about why you have the 3 trials and a range of lengths • What could you do to extend or improve your research (a new question)?

Variables = conditions that are controlled or measured There are 3 types: • The condition you change to see what happens = independent variable. Eg. Length of string • What you measure that depends on the condition you changed = dependent variable Eg. Time to complete 10 swings • The conditions you need to keep the same to make it a fair test = fixed variables Eg.

a new question If we used larger washers, what results would we get? What would happen if we did not start the pendulum form horizontal? Would the results be the same if we did a 360 deg full swing? Why did this happen? What if the wind blew on it, would it be the same?

Report Format Introduction This may include question and hypothesis In this report we investigated how the length of the pendulum string is related to the time taken for the swings . Method We tied a washer to each length of string so it could swing back and forth. Etc. Data length Time taken for 10swings 10 - 10 15 - 16 30 - 26 Analysis Look a the graph of our data. Etc Conclusions Our hypothesis for this lab was that the shorter string would swing faster. The data supports this hypothesis. Etc. Discussion of the Results We noticed that the pendulum was swinging much slower when the string was longer. Etc. • Use headings • For a formal lab report, include a cover page • Include the date • Report should be neat and well organized.

Departing thoughts … "Today, we benefit tremendously from the records of accomplishments and failures of people who have come before us.” “The people who took the time to accurately record their efforts, decisions, measurements, tests and conclusions are the same people who will live forever in their records and will serve as guides for future generations.”

The End! Science at Work

Reporting on a Science Investigation