Geography

Week 18: https://commons.wikimedia.org/wiki/File:Cherry_Blossoms_and_Washington_Monument.jpg Wendy Harman from Washington DC, USA / CC BY (https://creativecommons.org/licenses/by/2.0)
https://commons.wikimedia.org/wiki/File:Liberty_Bell_2008.jpg Tony the Misfit on Flickr / CC BY (https://creativecommons.org/licenses/by/2.0)

History

Week 14:
https://commons.wikimedia.org/wiki/File:Sheep_and_cow_in_South_Africa.jpg Lollie-Pop from Cape Town, South Africa / CC BY (https://creativecommons.org/licenses/by/2.0)

Science

Week 2: https://commons.wikimedia.org/wiki/File:Plasma_lamp_touching.jpg Diliff / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Week 8: https://commons.wikimedia.org/wiki/File:Dry_ice_pellet_subliming_in_water.jpg Steve Jurvetson / CC BY (https://creativecommons.org/licenses/by/2.0)

Week 10: https://commons.wikimedia.org/wiki/File:Artsy_density_column.png Kelvinsong / CC BY (https://creativecommons.org/licenses/by/3.0)

Week 14: https://commons.wikimedia.org/wiki/File:Nucleus_drawing.svg Marekich / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
https://commons.wikimedia.org/wiki/File:Quark_structure_proton.svg Arpad Horvath / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.5)
https://commons.wikimedia.org/wiki/File:Quark_structure_neutron.svg No machine-readable author provided. Harp assumed (based on copyright claims). / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.5)
https://commons.wikimedia.org/wiki/File:HydrogenOrbitalsN6L0M0.png Carlo Barraco / GPL (http://www.gnu.org/licenses/gpl.html) Link to video using pictures: https://vimeo.com/374192208

Week 16: https://commons.wikimedia.org/wiki/File:Atomic_number_depiction.jpg CC BY https://creativecommons.org/publicdomain/zero/1.0/deed.en 

Week 17: https://commons.wikimedia.org/wiki/File:NaF.gif Wdcf / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
https://commons.wikimedia.org/wiki/File:Covalent_bond_hydrogen.svg Jacek FH / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0) Link to video using pictures: https://vimeo.com/374192231

Week 23: https://commons.wikimedia.org/wiki/File:Water_salinity_diagram.png Peter Summerlin / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0) Link to video using pictures: https://vimeo.com/374192273

Week 27: https://commons.wikimedia.org/wiki/File:Universal_indicator_paper.jpg Bordercolliez / CC0

Scripture

Week 3: https://commons.wikimedia.org/wiki/File:Forest_sunrise.jpg Peter Heeling / CC0