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Teacher Resources

Overcrowding in the Science Laboratory



What is the maximum number of students you should have in your science laboratory? How much lab space should be available for each science student?

These are two of the most frequently asked questions we receive each year. The frequency of these questions points out the safety consciousness of today's science teacher. This article is intended to provide you with guidelines on how to help solve the problem of overcrowding in the science laboratory. We hope you and your administration will evaluate and adopt these guidelines in an effort to provide a safer working and improved learning environment for teachers and students.

Many school districts are experiencing budget problems. Any and all solutions to reduce school spending are being considered. One of the many solutions school administrators are considering to help "ease" budget problems is to increase the number of students in each class. Increasing class size not only delays the need to hire additional teaching staff, but also postpones the need to provide additional classroom space. For the science laboratory this solution creates major problems.

Health and Safety Concerns

Science teachers sense that overcrowded conditions in their science laboratories contribute to lab accidents. Their safety sense has not failed them! Overcrowding in the science laboratory is a major contributing factor to the safety problems school science departments face today.

In 1988, a report published in the Florida Science Teachers Magazine, Spring Edition, 1988, by Phillip Horton entitled "Class Size and Lab Safety in Florida" documented that over 55% of the science classes had enrollments teachers considered to be "potentially unsafe" for lab work. The average class size in these "unsafe" classrooms was 31 students. Of the 45% of the science classrooms teachers considered to be "safe", the average class size was 23 students. One high school teacher surveyed had two classes where the number of students was within the designed enrollment capacity, and three classes where enrollments exceeded the room capacity. He said "Contrasting the number of accidents between the first two periods and the last three ... class size does make a significant difference in traffic flow, individual monitoring, and understanding of the students!" The facts are clear, increasing the number of students in a science laboratory increases the likelihood of accidents. A high pupil/teacher ratio constitutes a threat to laboratory safety.

While we are concerned about the safety of the students, let's not forget that overcrowded conditions in the science laboratory also present an unsafe working environment for the science teacher as an employee of the school district. Most science laboratories are designed to accommodate 24 students, an accepted professional standard. When class sizes are larger than 24 students, it becomes very difficult for the science teacher to safely handle, transport and use laboratory chemicals and equipment. Increased class size puts "at risk" the health and safety of the science teacher.

Academic Concerns

Though student safety in the science laboratory is a major reason for limiting class size, another consideration is the ability to provide quality laboratory instruction. Many laboratory experiences require a high degree of student-teacher interaction. The fewer students there are in a laboratory, the greater the opportunity for students to ask questions and for teachers to clarify procedures and encourage the development of reasoning skills.

The amount of personal instruction provided each student must be considered. As one teacher who was teaching in an overcrowded science laboratory put it, "There is simply not enough teacher to go around and give sufficient time to each student."

Science teachers report that their classes are being held in rooms that were never designed for the teaching of science. Other teachers have had to discontinue the number of hands-on labs they do each year because they now have less preparation and setup time.

Overcrowding also increases discipline problems. In a lab situation, discipline problems only result in "unsafe" conditions.

Class sizes in some schools have grown so large that teachers no longer run hands-on labs because of unsafe conditions caused by overcrowding. Apparently some teachers have concluded that the risks involved in conducting labs in overcrowded laboratories are greater than the benefits the lab experiences provide. How many science laboratories are considered "safe" because the lab work has been removed from the curriculum? Is this the direction we want science education to go? I think not!

The Professional Standard

When discussing the issue of overcrowding, teachers and administrators should evaluate not only class size, but also the amount of space provided each student in the science laboratory.

The National Fire Protection Association (NFPA) characterizes the science laboratory as a vocational subject area. Fifty (50) square feet of net free space per student is the amount of space required as per the provisions of the NFPA 101 Life Safety Code®. Fifty square feet per student would be an area approximately 7' long x 7' wide, plus lab tables and benches.

The California Administrative Code [Title 2 Subchapter 4, Section 1811 (g)] requires that school design provide 1300 square feet for 24 students. This figure includes preparation areas as well as apparatus and chemical storage space.

The state of Vermont's revised standards for approving Vermont's public schools (Section 2160.4, Page 15; adopted January 2, 1991) states "No science laboratory class enrollment shall exceed the capacity of the available lab stations." This revised standard further states (Section 2191, Page 36, adopted January 2, 1991) that "classrooms are free of overcrowding and suited to the teaching strategies employed."

Vermont's School Buildings And Sites-Approval of Projects For State Aid Purposes (6200) states under the heading of floor area for the science laboratory (6241.1) that "50 square feet/student" be provided.

In Texas, the Texas Education Agency (TEA) has published Planning a Safe and Effective Science Learning Environment. On page 14 under High School Science Facilities it states: "Science classes should be limited to a maximum of 24 students in any one class provided adequate laboratory space exists for this number. It should be noted that 24 is not an average enrollment but a maximum in any one class." This publication was developed to aid Texas school administrators, teachers and architects to meet the instructional requirements of Title 19, Chapter 75 of the Texas Administrative Code.

The State of Georgia IEC Code #160-5-1-.08 entitled Class Size states: "The purpose of this rule is to establish maximum class sizes and guidelines for the computation of class size and system average class size." The ruling goes on to say that science labs should not exceed a "maximum system average class size of 24.2 students or a maximum individual class size of 28."

In the book Pathways to the Science Standards-High School Edition1 it states: "Space is an important factor in promoting inquiry, collaborative learning, and safety. Considering current technology needs and teaching practices, a good science room will require a minimum of 60 ft.2 per pupil (5.6 m2), which is equivalent to 1,440 ft.2 (134 m2) to accommodate a class of 24 safely in a combination laboratory/classroom-or-a minimum of 45 ft.2 per pupil (4.2 m2), which is equivalent to 1,080 ft.2 (101 m2) to accommodate a class of 24 safely in a stand-alone laboratory. In addition, 10 ft.2 (0.9 m2) per student is needed for teacher preparation space and for separate storage space (240 ft.2 or 22 m2, for a class of 24)."

It is important to note that Pathways to the Science Standards-High School Edition is a guidebook which provides step-by-step guidance on what the National Science Standards mean and how to begin to implement change in the classroom. This is very powerful information you can use in your fight to keep class size down to a reasonable number of students.

In 1986 the National Science Teachers Association (NSTA) and the National Science Supervisors Association (NSSA) adopted a statement entitled "Working Conditions for Secondary Classroom Teachers." In paragraph VI it states "Because of safety considerations and the individual attention needed by students in laboratories, science classes should be limited to 24 students unless a team of teachers is available."

In 1990 the National Science Teachers Association (NSTA) adopted a position statement entitled "Laboratory Science." Here they said: "The number of students assigned to each laboratory class should not exceed 24. The student must have immediate access to the teacher in order to provide a safe and effective learning environment."

The above stated positions establish professional standards that are sensible and defensible in that both space per student and class size limit are specified.

A final area of focus is the science teacher as an employee of the school district. The Occupational Safety and Health Administration's (OSHA) 1990 29 CFR Part 1910 requires a safe working environment for employees relative to the use of chemicals in science laboratories. A student/teacher ratio above the professional standards described above creates greater risk of accidents, not only for students, but also for school employees.

The Need for Action

As the science teacher, science department chairperson, or science supervisor of your school district, you are considered to be the "house expert in science." Please do not assume your school administration understands the problems of overcrowding in the science laboratory. It is your responsibility as the "house expert in science" to provide your administration with as much information as you can on this topic. Diplomatically explain to your administration, in writing, why overcrowding in the science laboratory is a problem. Once your school administration is informed of the problem and understands the consequences of overcrowding in the science laboratory, we are sure most schools will try to take some type of corrective action to reduce the number of students in the science laboratory.

If your administration is unable to take corrective action or simply fails to understand the problems of overcrowding in the science laboratory, then the school district administration must take full responsibility for their decision. Explain to your school administration, in writing, that you disagree with their decision. Be specific and detail each reason why you are against overcrowding in the science laboratory. Tell the school district that they, not you, will be held responsible for accidents which occur because of their decision to increase your class size. Since they insist on a larger class size, they also need to be aware of the increased liability they have taken upon themselves.

The content of this second letter should be very similar to the earlier letter you sent the school district. This letter should also be sent certified mail-return receipt requested. The signed receipt will provide you with proof that the school district has received your letter.

If you feel these steps are not enough, then we offer one last option which you might want to consider. However, we must strongly warn you that using this option, may get you into some serious "political" hot water.

The option is to involve parents. If parents find out their children's safety is at risk due to overcrowded science laboratories, they will get involved! If parents find out their children are not getting the kind of quality education they deserve because of overcrowded science laboratories, they will get involved! Parents can be very "vocal!" They may be the catalyst you need to have your school district administration solve the problem of overcrowding in the science laboratory.

Remember, the best option of all is to work with your school administration. Together you both can solve the problem of overcrowding in the science laboratory.

Final Thoughts

Overcrowding in the science laboratory is a serious problem. I hope we have provided you with the information you need to argue your case against overcrowding in the science laboratory. If you have other ideas we have not mentioned, please write to us. We will be more than happy to pass your ideas on to our readers in future issues of Flinn Fax.

1Pathways to the Science Standards-High School Edition is published by the National Science Teachers Association. The book is 189 pages, easy to read, and is an absolute must for every secondary science teacher.




I was very fortunate to have several outstanding science educators
help me develop this article. Special thanks and credit to:
Kenneth Russell Roy
Executive Director
National Science Supervisors Assoc.          
Al Kousen
State Science Consultant
Vermont State Department of Education
James W. Collins
Director of Science
Texas Education Agency
Doug Chiappetta
Chief-School Improvement Unit
Vermont State Department of Education
Rita Hoots
Yuba Community College District
Woodland, California
Bob Moore
Science Consultant
Georgia State Department of Education

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