On a hot day, a child drinks all the water in a plastic bottle. She then screws the cap back tightly on the bottle, so that the bottle contains only air. She throws the
bottle into a wastebasket, where the Sun shines on it. After a while in the Sun's rays,
the air in the bottle is much hotter than before.
cap screwed on
(i) State what has happened to the pressure of the air in the bottle.
Give a reason for your answer.
(ii) In terms of the behaviour of the air molecules, explain your answer
to a(i)

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

If you place a magnet under a clear dish, and sprinkle iron fillings over it, above what part of the magnet will most of the fillings gather