a solar water bag can be used to heat water for an outside swimming pool. A student wanted to find out if the colour of the solar water bag affects the temperature increase of the water inside the bag. (black bag, pale blue bag, pale green bag, white bag) 1. fill each bag with water 2. place the four bags on the ground outside 3. after three hours, measure the temperature of the water inside each bag 4. repeat steps 1-3 on the next two days. (a) suggest three changes the student should make to this method to get valid results.​