This week on Dear Science, Marcus takes Jemima and Zazi through a wide range of scientific topics.

Marcus talks about the impact of a giant tsunami from a dino-killing asteroid, revealed in fossilized ‘megaripples’.

Jemima and Zazi learn about a landmark research integrity survey, finding questionable practices are surprisingly common.

Finally, Marcus explains that the quarter-dose of Moderna COVID vaccine still rouses a big immune response.