How many labs?

[JudoMom]

Approximately how many labs (or how many lab hours) are usually done to have a high school science course count as a lab science on a transcript?

[joannqn]

I don't know what is typical, but Science Shepherd Biology has 20 labs.  The first one is not really a lab, but rather information on the scientific method, how to draw good lab drawings, and the parts of a microscope.  Labs 16 and 17 are essentially the same, both are on classification, but different things are classified in the different labs; lab 17 is listed as optional.  The other 18 labs are more lab-like.

[Kendall]

I will be interested to see responses about this as well.  The Landry Chemistry intensive that my son attended did 14.  The teacher there was a former public school teacher who indicated that the school she was in did not do near 14 labs per year in chemistry.  I hope someone with experience in brick and mortar schools will respond.

[bobbeym]

Our DIVE CD has 29 labs included. 

 

DS19 said his B&M PS did 1 lab every 6 weeks for both Bio and Chem.

[Mom22ns]

We aim for 30-40 hours of lab, but usually do that in 2 hour segments. There is no minimum and I've seen people post that they only do a couple and count it, but I would think 10 labs would be pretty minimal.

[regentrude]

We aim for 30-40 hours of lab, but usually do that in 2 hour segments. There is no minimum and I've seen people post that they only do a couple and count it, but I would think 10 labs would be pretty minimal.

 

For our physics at home, we did 10 labs with DD, which translated to about 40 hours.

 

It all depends on the quality of the lab, not the number of labs or the length of each lab. Neither number nor duration is a good measure for the amount of learning taking place.

 

I can have a few labs with a thorough, clean experiment and a rigorous data analysis, including statistics, error analysis, plotting and fitting  and detailed comparison to theoretical predictions, where my student learns a ton.

I can have a large number of labs where the student just follows instructions and performs copious amounts of procedures, but where a computer is used for automatic data gathering and outputting data without any in-depth thinking.

 

A student may learn more from one single well designed thorough home lab exercise than from an entire semester of mediocre weekly labs.

[Kareni]

I'm sure you'll receive a variety of answers. For her Chemistry lab, my daughter used the MicroChem Kit. That had seventeen labs.

Regards,
Kareni

[JudoMom]

Thanks!  This has been helpful.  

[SailorMom]

We aim for about a lab a week-ish.  I suppose around 20-30 hours would be about what we end up with....

[kroe1]

1 to 2 labs a week, usually an hour or much less each lab. We finished with about 60 labs this past year for physical science.

[regentrude]

1 to 2 labs a week, usually an hour or much less each lab.

 

Just curious: how does your student manage to set up and perform an experiment, analyze the data, and write a lab report in an hour or even much less than one hour? We found that even for a simple experiment (pendulum, spring etc), the data analysis alone took longer.

[kroe1]

The labs we did with A Beka usually took the entire hour. But I would already have the equipment set out on the counter. A Beka labs are designed for about 1 hour, I believe. At least we rarely have had any of their labs go longer. So for example, when there were experiments with the Van de Graff generator, I would get out the big rubber mat from the garage, set out the generator, tear up styrofoam pieces, etc. while DD was practicing piano. It is quick for me because our lab is so organized. It was easy for her to obtain data, fill out her lab manual, and do whatever write up was required in an hour or less. She is a speed demon just like her mom and dad.

 

For our non-A Beka labs, most are small kits which are observational or more simplistic and can be done in 15 to 30 minutes easily.

 

Some of our equipment is designed for speed as well. While others, are firing up little Bunsen burners, I have big, heavy ring stands that fit right on the gas stove complete with hood overhead. We use digital scales for measuring and a large magnetic stirrer for mixing. Most colleges would kill to have our equipment. My DH and I are both heavily involved in the medical sciences and this collection of equipment has been occurring over many many years.

 

Finally, we repeat labs for data collection only 3 times. Many labs call for 5.

 

Hope that answers your question. I would say the biggest help for us is having everything right there and ready to go before the experiment starts.

[Hikin' Mama]

Regentrude, do you have a resource(s) you could recommend for setting up and conducting good labs? I'm really enjoying science with my daughter, although that is not my background. Thank you!

[regentrude]

Regentrude, do you have a resource(s) you could recommend for setting up and conducting good labs?

 

No, I am sorry, I don't have any. But I can tell you a few things that will contribute to making a good physics lab:

 

Design a simple experiment. You do not need complicated expensive equipment to teach a student good lab work. The rigor is in the analysis.

 

Ask a good question that can be answered by experimentation. It should be clear which variables are varied, which are fixed, and which quantity is the one whose behavior you study.

 

Have the student repeat each measurement often enough to do some statistics. Get an average and see how much the values vary around the average; that is a good estimate for the experimental error. Document procedure and ALL data (even ones where you think the measurement was screwed up) in a bound lab notebook with numbered pages.

 

The student should contemplate the experimental error and try to identify its sources.

 

Vary the independent variable in increments. Graph your data.

 

When teaching graphing, it is very important that the student learns to select appropriate axes for his graph, making sure the range of his variables represents the data he has obtained. The data should extend across the entire graph and not be clustered in one corner with orders of magnitude unexplored. I would strongly recommend graphing by hand, because the students learns much more than by putting it into a computer program.

The method of graphing should be appropriate to the data. If the data follow a power law relationship, a graph on logarithmic axes will be a straight line; this is better to grasp visually and easier to fit.

Error bars should be in the graph. Any fit does not have to go through the data points themselves, but should be within the error bars.

 

A discussion should include a comparison with theoretical predictions if available.

 

One of the best labs we have done was a simple pendulum: a plastic spice jar filled with marbles, at the end of a string that was suspended from the ceiling. We investigated how the time for one full swing depends on mass, length of string, and amplitude of the swing. It was very easy to set up with common household items, but the analysis was college level. Each variable was varied independently which the other two were kept constant, the student repeated each measurement often enough to get good statistics.

[Hikin' Mama]

Thank you! That is very helpful!