NEW AQA Physics GCSE - Upthrust and Flotation

This lesson is designed for the NEW AQA Physics GCSE, particularly the ‘Force and pressure’ SoW.

For more lessons designed to meet specification points for the NEW AQA Trilogy specifications for Biology, Chemistry and Physics please see my shop: https://www.tes.com/teaching-resources/shop/SWiftScience

The lesson begins with a definition of upthrust, including a diagram to demonstrate. Students will then be asked to complete a sketch of a boat in their books, along with arrows to demonstrate the forces acting upon the boat, and a copy and complete task.

Next, students will complete an investigation into upthrust, a worksheet is provided as part of the resources which includes a method which outlines how students can measure the upthrust of different objects in water, and other mediums too (e.g. salt water). Students should work in groups, and record findings in their books. After a short class discussion about finding, the following slides on the PowerPoint explain upthrust in terms of particles, pressure and force.

The next part of the lesson focuses on flotation. Firstly, students are told that an object will float when its weight is equal to its upthrust, and will sink if its weight is greater than upthrust. Students are then asked to consider why different objects of the same mass, behave differently in water. Students will be reintroduced to the idea of density.

On the next slide, students will use the density of different materials to determine whether they will float or sink in water. Students will then be shown the density calculation, which they will be familiar with from previous lessons on density. They will be given a quick check of questions to practice using the density calculation, which can then be marked using the answers provided.

Lastly, an explanation is provided for students for why density is important in float tests. The last task is a worksheet of questions on the topic of upthrust and flotation, students can answer the questions in their books and then use the mark scheme to assess their work.

The plenary task requires students to write a Whatsapp message to a friend to summarize what they have learned in today’s lesson.

All resources are included. Thanks for looking, if you have any questions please let me know in the comments section and any feedback would be appreciated.