up
466

To Write a Lab Report

  1. Question the situation.
    • Subject: What is the topic of the experiment that you will report on?
    • Purpose: What is the purpose of the experiment? Are you writing to provide a procedure to replicate, to provide raw data, to interpret results, or all three?
    • Audience: Who will read the report? What do they need to know?
  2. Plan your report.
    • Identify your topic, the scientific question that you will explore and test.

      Topic: Decomposition

      Thought: How efficient are decomposers?

      Hypothesis: Different types of decomposers draw different nutrients from decaying material, so a suite of different types will be most efficient.

    • Become familiar with the appropriate form for a lab report, one provided by your teacher or the one on pages 467–468.
  3. Research your topic.
    • Searching: Conduct your experiment using the scientific method (see pages 54–57). Take thorough notes.
    • Focusing: Use observations and results to draw conclusions.

      Observation: Fruits decomposed by fly larvae and fungi were reduced much more rapidly and completely than those decomposed only by fungi.

    • Shaping: Arrange the details of your report.
  4. Create the first draft of your report.
    • Begin with your scientific question and hypothesis.
    • Follow with the materials, step-by-step procedure, and observations.
    • End with the conclusions based on your findings.
  5. Improve your first draft.
    • Evaluate your first draft.

      Purpose: Does the report effectively explain or describe the experiment and results as you planned?

      Audience: Will the reader be able to follow your report?

    • Revise your writing.

      Rewrite parts that are confusing or unclear.

      Add details as needed.

      Cut parts that don’t relate to the topic.

      Reorder sentences or parts that are out of order.

    • Edit your revised writing.

      Replace general nouns and verbs with specific ones.

      Check your writing for accuracy using pages 190–195 as a guide.

  6. Present the final copy of your lab report to a classroom blog or use it to lead classmates through the same procedure.
467

Lab Report

The following lab report comes from Eli King, a high school student at Burlington High School in Burlington, Wisconsin. In his lab report, Eli discusses the outcomes of a modern Galileo experiment, exploring the relationship between gravity, velocity, and acceleration.

The beginning includes a title, a question, and a hypothesis about the question.

Modern Galileo Experiment

Question: What is the relationship between velocity and acceleration? How does gravity provide uniform deceleration and acceleration?

Hypothesis: Just as Galileo observed, the acceleration of the cart should be constant.

The middle includes a background section that defines the variables that will be measured and used for calculations.

Background:

Gravity = −9.81 meters/second²

Acceleration = a = Δv ⁄ Δt = (vfinal − vinitial) ⁄ (tfinal − tinitial)

a = acceleration (meters/second2)

v = final velocity (meters/second)

u = initial velocity (meters/second)

t = time (second)

The materials and procedure sections outline what other people would need to replicate the experiment.

Materials: Cart, motion detector, graphing calculator

Procedure:

  1. Set up a motion detector at the top of an incline.
  2. Release a cart. Let it roll freely down the incline.
  3. Record data from the motion detector. Observe the increase in speed and the constant acceleration.
  4. Repeat procedure, this time pushing the cart up the ramp and letting it freely roll back down.
  5. Observe the quadratic qualities of velocity, time, and acceleration.
  6. Calculate the average acceleration.
The raw data appears in a table.

Data:

Table (Initial Test)

 
468
This observation provides a general inference drawn from data.

Observations:

Despite a few values at the beginning, change in speed (acceleration) is almost perfectly constant. Our own calculation of acceleration was very close to the projected slope from the motion sensor.

The conclusions section reviews the experiment, showing how the evidence supported the hypothesis.

Conclusions:

Hypothesis

We wanted to examine the relationship between velocity and acceleration, as well as the effect of a constant acceleration (gravity). We successfully graphed the motion of our cart as it traveled along the ramp. Our findings revealed a mathematical relationship between acceleration, speed, and position.

Evidence

Our data confirms Galileo’s hypothesis—acceleration is constant. (Ours was nearly constant.) We observed an exponential increase in speed as the cart traveled down the ramp. The journey back down mirrored the trip up, revealing a mirror quadratic relationship between the up and down journeys. This demonstrates that acceleration is constant.

A reliability section discusses the precautions taken to avoid experimental error.

Reliability

This experiment was set up in a way that yielded little human error. We used machines to graph points and observe relationships, harnessing pure data. The only interferences may have occurred during the different cart releases. Perhaps different amounts of force were applied on the cart during different releases. However, even these slight interferences didn’t affect the data as a whole.

The ending discusses applying the results of the experiment to life.

Application

This type of knowledge applies to many different real-world scenarios. For instance, throwing a ball straight up in the air and observing its descent exemplifies this idea. It also works in engineering, such as roller coaster design. By examining velocity, acceleration, and angles, roller coaster engineers can design effective and safe rides. These ideas also help calculate the stopping distance of a car. The technical aspects of velocity and acceleration are everywhere, and we often take them for granted.

 
up

Additional Resources

Web Page: Writing Lab Reports

Web Page: Tips on Writing Lab Reports