432px-moon_earth_sun_dtal.jpgI’ve posted a new episode of my Science Teaching Tips podcast: Private theories. TI Director Linda Shore was one of the people originally involved in the Private Universe video (from Annenburg Media), which showed surprisingly persistent misconceptions in students. In the famous opening scene, they interview students as they graduate from Harvard and ask them why there are seasons. Almost all of them said that it’s because the earth gets closer to the sun during 1/2 of its orbit, despite the fact that this doesn’t explain why the southern hemisphere has summer while the northern hemisphere has winter. [The real answer is that the planet is tipped on its axis, so 1/2 of it is closer to the sun during part of the year].

In this podcast, Linda Shore explains how she probes student thinking to find out about their private theories about the universe. Without understanding what students are thinking, it’s very difficult to help them form new conceptions of the world.