Australia's Science Forum

What sort of pracs do you guys do with your biology classes to examine the effect of exercise on the respiratory & circulatory systems?

Anything different to the usual heart rate/CO2 production stuff?

Well, you gotta admit, heart rate & CO2 production Do kinda cover respiration & circulatory systems. We own a "gun" digital thermometer, and we get a fair-skinned child (ranga's work best ) to run around, then we take their surface temp on their cheeks (usually red & flushed) and their foreheads (usually sweaty). There is a definite difference in the surface temp, and the sweaty forehead is cooler, demonstrating that Homeostasis works.

What specific heart rate/CO2 things do you do now?

We do the same thing except they run up and down the steps

Just the standard breathing into bromothymol blue before & after running around, & adding ammonia dropwise to bring the colour back.
Heart rate is taking pulse before & after running around, & we also do breath holding timed before & after running around.
They cover the bases topic-wise, but I was just wondering if anyone had something different to the usual.

I love your idea Smiley......I might have to get a digital thermometer, then have the fun of walking through the classes, looking intently at each kid to choose the best one for the task

Bindi,

I use a datalogger and a CO2 gas probe. 1st get the kids to breathe out into an empty freezer bag, and then insert the probe and read the CO2 level. Then get them to hold their breath for 45 seconds (or longer ) and breathe into a bag & read again. Then get them to run - up & down stairs or whatever - and breathe into the bag again, and the CO2 level should have changed significantly.

We use one of those blood pressure monitors to test heart rate, because they give a pulse reading as well as blood pressure. We do before, immediately after and then 5 mins after to check out how long it takes for kids to get back to their RHR. The fitter they are, the quicker they return to RHR.

bindibadgi wrote: ↑28 Jul 2011, 10:15 Just the standard breathing into bromothymol blue before & after running around, & adding ammonia dropwise to bring the colour back.
Heart rate is taking pulse before & after running around, & we also do breath holding timed before & after running around.
They cover the bases topic-wise, but I was just wondering if anyone had something different to the usual.

I love your idea Smiley......I might have to get a digital thermometer, then have the fun of walking through the classes, looking intently at each kid to choose the best one for the task

I was just wondering exactly how the bromothymol blue part works. I know that breathing into the bromothymol blue turns it yellow because of the CO2 but how do you make it a quantitative test? Do you do a certain number of breaths and measure how much ammonia to return it to blue or measure how many breaths to turn it yellow in the first place?