Heat Transfer in Nature
Class 7 · Science · 12 Questions
A smoke detector is a device that detects smoke and sounds an alarm. Suppose you are fitting a smoke detector in your room. The most suitable place for this device will be
A shopkeeper serves you cold lassi in a tumbler. By chance, the tumbler had a small leak. You were given another tumbler by the shopkeeper to put the leaky tumbler in it. Will this arrangement help to keep the lassi cold for a longer time? Explain.
State with reason(s) whether the following statements are True [T] or False [F]. (i) Heat transfer takes place in solids through convection. (ii) Heat transfer through convection takes place by the actual movement of particles. (iii) Areas with clay materials allow more seepage of water than those with sandy materials. (iv) The movement of cooler air from land to sea is called land breeze.
Some ice cubes placed in a dish melt into water after sometime. Where do the ice cubes get heat for this transformation?
A burning incense stick is fixed, pointing downwards. In which direction would the smoke from the incense stick move? Show the movement of smoke with a diagram.
Why are hollow bricks used to construct the outer walls of houses in hot regions?
Explain how large water bodies prevent extreme temperature in areas around them.
Explain how water seeps through the surface of the Earth and gets stored as groundwater.
The water cycle helps in the redistribution and replenishment of water on the Earth. Justify the statement.
Visit a site of water harvesting or a recharge pit. Find out from people how they are constructed and how they work. Prepare a report with illustrations.
Tightly wrap a thin paper strip around a metallic rod. Try to burn the paper with a candle while rotating the rod continuously. Does the paper burn? Explain your observations.
Take a sheet of paper. Draw a spiral on it. Cut the paper along the spiral. Suspend the paper above a burning candle. Observe what happens. Provide an explanation for your observation.