Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Speaker one All right. So have you ever left your milk outside the fridge at room temperature, and then wondered why it’s gone sour and then smelt sort of weird? Speaker two No, (laughs) but. it’s ...

Speaker one Have you ever had a bump or a sprain and needed a cold compress? Speaker two Yes, all the time. Now, some cold packs use a chemical reaction to absorb heat. This is an example of something ...