Liquid in Burning Tree

As a branch heated up in the campfire, a liquid started dripping out of the bark. 

• What is the bubbling liquid coming from the branch?

• Why do campfires crackle?
• What is inside a tree branch?
• What changes happen to a branch when it’s heated up?
• Does a tree permanently change after a fire or can it be reversed?
• Is that sap? Water? What is the difference between sap and water?

Students could:

• Generate questions about the phenomena.
• Ask students to identify what is inside a tree branch (wood, bark, air pockets, sap, etc) and identify the state of matter of each of those items. If possible bring a tree branch to the room and cut open for students to observe.
• Experiment with matter changes caused by heating and cooling using examples such as:    
  • Melting crayons and refreezing
  • Melting ice and refreezing
  • Freezing a leaf and thawing
• Create a cause and effect chart when experimenting with matter changes.
• Make a claim about when matter changes cannot be reversed. Support with evidence.
  • Students can safely observe what happens to paper after it is burned.
  • Students can view photographs or videos of forests after a forest fire.

• The Conversation | Curious Kids: why does wood crackle in a fire?: The author answers the question ‘why does wood crackle in a fire?’ It also addresses how branches contain water and sap in air pockets and that’s what is seen coming out of the branch in the fire.
• PBS LearningMedia | ScienceTrek: Wildfire: Wildfires are a natural part of the ecosystem, but they can get out of control and cause lots of damage. Find out about wildfires and what it takes to put a fire out.