Experiments are an important part of physics and it naturally follows that lab activities is important in physics education. While there are a great number of methods for lab activities that all have varying effects, this study seeks to answer how they interact with one of the most important tools in education, formative assessment. We have explored this topic by reviewing scientific articles on both physics lab activities as well as formative assessment in its many forms. To connect it to a more practical and Swedish context, we also surveyed Swedish physics teachers at different levels of education and performed a thematic analysis to see how they approach lab activities and what, if any, formative assessment they implement. From the scientific review we found that we can divide the physics lab activities into minimally and heavily guided. The minimally guided support abilities like critical thinking and considering sources of error, while heavily guided lab activities are more suited training procedural abilities, such as handling lab equipment, or for students with no prior experience with labs. Formative assessment can be implemented  with positive effects regardless of lab activity. Especially self and peer assessment show great results and should be viewed as a regular part of the teaching methodology for lab activities. The survey, which had 12 respondents, indicated that self and peer assessment are not used on a regular basis prior to university and the lab activities start out from heavily guided and moves towards minimally guided. The main challenge against changing both of these was time. To aid teachers in implementing the effective lab activities, proposed by the research literature, we prepared a lab activity in Swedish alongside considerations for implementations, formative assessment and a rubric.