To view these resources with no ads, please Login or Subscribe to help support our content development.
School subscriptions can access more than 175 downloadable unit bundles in our store for free (a value of $1,500).
District subscriptions provide huge group discounts for their schools. Email for a quote: sheri@exploringnature.org.
Henrietta Swan Leavitt was a Harvard astronomer who, in 1908, discovered how to calculate how far away stars are from the earth. Comparing a star's true brightness to its apparent brightness seen through a telescope.
To view these resources with no ads, please Login or Subscribe to help support our content development.
School subscriptions can access more than 175 downloadable unit bundles in our store for free (a value of $1,500).
District subscriptions provide huge group discounts for their schools. Email for a quote: sheri@exploringnature.org.
