Our current science unit is nutrition. After learning about the 5 food groups as well as extras, I set the students loose with the app Lil' Kitten Shopping Cart.
First mixed grade level pairs took a screenshot of the shopping list (5 items). They followed the game, finding and purchasing all the items on their list. They took a shot at the end, showing their shopping total. They brought both these screenshots into Educreations. While showing the first slide students explained what food group each item belonged to. On the 2nd slide they talked about how they determined which item to purchase. For example, the game has several types of ice cream and they are sold at different prices. Some students purchased the cheaper items to save money while other groups decided to purchase pricier items because they figured it was higher quality or a larger quantity or a more well-known brand. These were all concepts we had talked about prior to the activity. Finally students had to show work to determine what types of bills and/or coins they could have received back as change.
Unfortunately we ran into some technical difficulties with our Internet and these projects still haven't come off the iPads. However, the activity worked well.