Day Length Differences Throughout Year ```Name: Anabela Status: other Grade: other Location: NV Country: N/A Date: N/A ``` Question: I have been a secondary teacher for many years but after my retirement I have decided to teach primary school children (6-10 years old). I have a degree and Ph.D in physics, but is difficult for me (!) to find an easy and adequate way of teaching to children aged 6-7 years old about "Why days and nights have different duration along the year"... Could you please help me? Replies: Anabela, Whenever something becomes difficult for me to teach, I tend to always rely on an activity of some kind that will help drive ideas home. By having the students actually do the activity and guide them to -not tell them- the conclusions I want, I find that their learning is much improved and they have fun in the process. You know that the different day/night duration is a function of the tilt in the axis of a spheroid (not perfectly spherical) Earth. So how about putting an egg on a slowly rotating clamp, putting a dot on the egg, and timing how long that dot stays within the light of a flashlight at different angles of incidence? The trick is to get some kind of rotor that will rotate the egg at a careful and consistent pace. Greg (Roberto Gregorius) ---Or a beach ball (Nathan A. Unterman) It is hard to explain this concept to seven year olds. The answer should include the idea that Earth is tilted, and that when the tilt is sharp, as in Northern hemisp[here winter, the nights are longer. Also you might introduce the concept that we live on a spaceship, and this is how our ship flies through space. David H. Levy Hello Anabela, First, a great-big-THANK YOU for teaching! I am not an educator and do not have any factual, tested knowledge of how children best learn. That said, the idea that best occurs to me is not an explanation. Rather it seems that for children that young the best way might be through showing them with a model of the solar system. The canonical version of this is the incandescent light bulb "sun" and then balls as the planets to orbit the bulb. In your case, you could have a ball mounted on something (or even just handheld) that turns at a constant rate. Perhaps a line of constant latitude and a big spot on the ball to represent the actual location. Then show the kids summer with the spot inclined towards the sun and then winter on the opposite side from the bulb. In fact, you could have a one spot for the northern hemisphere and then a second colored spot for the southern hemisphere. If they're capable of grasping the time difference in days/nights of the two hemispheres and why it is summer on one half and winter on the other, then I think you've got it. If the ball turns slowly enough, say once every 30 seconds, perhaps you could even have them "time" day and night in both winter and summer with a stopwatch. I often think children are smarter than we adults give them credit for. As such, the bonus question would be to try and come up for a reason why the seasons change due to the earth's inclination and not because the "earth is closer to the sun in the summer, therefore hotter." Understanding that the reason for hot summers and longer days is not due to the earth being closer to the sun would be a great thing. Lastly, sadly, I've met too many adults that do not understand this. best wishes, Michael S. Pierce Materials Science Division Argonne National Laboratory Click here to return to the Astronomy Archives

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