[填空题]
An investigation was carried out f:juv6 la*k)f1+ 4iqru *ix9wpyd5ra into thlxay; (cs3/e taqht;kny))5 bp9ka/ae effects of household detergents on aquatic habitats. Scientists tested the effect of different household detergents on the surface9tkq( ts3ek;a)a;5c p/ly) /xbnaayh tension of water in order to better understand the impact they may have on organisms living on the surface.
A paper clip was folded slightly on one side and rested on the surface of the water, maintained at a constant temperature and contained within a water tank. Drops of detergent solution were slowly added to the water tank until the paperclip sank to the bottom. The volume of detergent solution taken to sink the paperclip was recorded.
Detergent solutions were made by adding 5 ml of detergent to 15 ml of water.
1.Describe the relationship between the volume of detergent solution added and the surface tension of water.
2.1.For the Easy Clean detergent, calculate the mean number of drops of detergent needed to sink the paper clip.
Mean = ml
2.2.Estimate how many drops of Easy Clean detergent solution it would take to sink 5 paper clips.
3.1.State one variable, other than those given, which would need to be controlled in this experiment in order to achieve a valid result.
3.2.Suggest one method that could be used to keep the water at a constant temperature.
3.3.Explain the importance of maintaining water at a constant temperature.
3.4.Identify one potential source of error in the methodology.
4.Suggest why different numbers of drops of detergent solution were needed to sink the paperclip between each type of detergent.
