Conducting an Experiment: (The Scientific Method in Action part 2)
Lesson 7 of 9
Objective: Students will follow procedures developed in the previous lesson to conduct an experiment and collect quantitative and qualitative data.
In this lesson, students will test their hypotheses about the effects of vertigo by conducting the experiment that they designed in the previous lesson.
Connection to Standard:
Regarding the standard, students must follow the multistep procedure they designed, and while doing so, may become aware of some of the faults in their initial design. This is ok... allow them to rework the experiment as they conduct it, just make sure they finish in the allotted time.
When it comes time to finally conduct the experiment, the most important consideration is that you conduct the experiment in a safe space. At my school, there is a large field separating the baseball and soccer fields and I take my classes there. Please, please, please keep in mind that students will be falling down frequently. The difference between this being comic and tragic really is the area you choose to conduct the experiment. Make sure to get advance permission from your principal and any relevant department (PE, custodial) before you schedule the experiment.
Before I take my classes to the field, I do a quick check to make sure all groups have the basic equipment to conduct the experiment:
- Pen/Pencil (for completing the written tasks and recording data)
- Double-sided written task worksheets (at least one per group member)
- Double-sided data table worksheets (at least one side per task, so generally 3 sheets per group)
- Paper (to record quantitative and qualitative data)
- Clipboard/and or Notebook (to place behind written task worksheets)
- A copy of their experimental design procedure (to follow the plan the designed in the last lesson)
I also recommend that students bring cell phones if they are equipped with stop watches and video cameras. It is especially useful if students record video of the physical tasks, which will allow them to make additional observations and record additional qualitative and quantitative data after the fact (they also make fun videos to show their friends and families).
I also bring additional equipment with me:
- Meter sticks (at least one per group)
- A few tubes of tennis balls
- Several meters worth of yarn, string, or thin rope
- Extra copies of the written task worksheet
- Extra copies of the data table worksheet*
- A loud whistle (to get all groups' attention)
After the materials check, I remind students of the importance of safety while conducting the experiment and encourage them to be aware of other groups and try and spread out once we arrive at the field so that no one bumps into each other.
After making sure that all groups are ready to begin, we walk as a class to the site of the experiment.
*The data tables may not be necessary for all students, especially if you prefer to assess students' ability to collect relevant data without scaffolding. For my part, I prefer to distribute them as a reminder that,
1. They have a lot of work to get done outside
2. They should be collecting both quantitative and qualitative data from each task
3. They need to collect data from a control group and an experimental group
If you prefer, you may distribute these sheets during the previous lesson so students have a better idea of the data collection requirements ahead of time.
Conducting the Experiment
Once we arrive at the site, I remind students that we will need to perform all tasks and collect their data during the limited time we have (if it is a 60 minute period, the actual time to collect data might end up being around 45-50 minutes, depending on how long it takes to get there), so it is important for them to stay on task.
Again, for safety considerations, I ask groups to spread out while they are performing physical tasks in order to keep them from running into each other.
As for the teacher’s role, I tend to try and keep an eye on all groups (if it is a large area, they may spread pretty far apart), and go to any groups that seem like they need some assistance. This may include, obviously, groups that are goofing off more than working, but can also include groups that seem inconsistent in how they are performing their tasks. In these cases, I ask to see the procedures section of their experimental design. I don’t always come out and say, “you have introduced additional variables”. I may instead hint at it with something like, “I see she’s spinning around really fast before her tasks but he’s just kind of slowly spinning… is that part of the design of your experiment?” In these cases, groups may adjust how they are conducting the experiment. If they continue as they had, it is still something they’ll have to address when they examine their work in the upcoming peer review lesson that covers experimental error.
Often enough, students are able to stay on task with this experiment because it’s simply fun. Depending on their design, there may also be a competitive element that keeps the students engaged and invested in completing the experiment (e.g., “let’s see who can walk the farthest without stepping off a straight line”).
It’s important to make yourself available as a resource to answer questions or offer guidance, but you shouldn’t ever find yourself in the position of telling students they’re “doing it wrong”. Remember that the point of this lesson, at least in part, is that they will make mistakes. This is a great way to allow them to learn from their mistakes while creating an environment of self-sufficiency and intellectual freedom, demonstrating to your students that they will be as responsible as the teacher for the learning that takes place in the course, rather than a straight “transmission” of facts from teacher to student.
It's very important to monitor all groups to make sure that students aren’t doing anything unsafe. It’s one thing to approve of a task in the classroom, but students can have a way of deviating from the safety plan once they’re outside having fun. Make sure to address safety issues as quickly as possible.
Additionally, there may be students that can not participate because of medical reasons. For students who in wheelchairs or on crutches, you may assign them a supporting role, either as the designated data recorder or videographer in a group, an equipment manager, or just an extra set of eyes to let you know if a group needs attention.
Be aware, too, that some students can get nauseous from spinning. This may be due to their design: as a general rule, students shouldn’t have planned to spin for any longer than 30 seconds… it almost always ends in them falling down. If this is the case, suggest they alter their procedure for less spinning time. If a student is nauseous from spinning, make it clear that they do not have to continue and that the group can make do with the limited data they’ve collected up to that point. Remember… safety first!
When there are about 15 minutes left in the period, I go around to each group and let them know they need to wrap up their tasks. After another five minutes, I’ll whistle or shout to get all groups’ attention and give everyone a “5 minute warning”.
When there are only about 5 minutes left, I’ll call all groups together and collect any of the supplies that I loaned to them. It may also be a good practice to collect data sheets in case the student that recorded the data is not present for the next lesson where students will analyze their data and write a lab report.