Describe an experiment to show that liquids expand and contract at different rates

Depend on the rate of temperature applied.

Explanation:

Liquid expands on heating.

When liquid is heated then there is an increase in the average speed of it's molecules as a result molecules starts moving faster and hence kinetic energy of the liquid also get increased. This kinetic energy is directly proportional to the temperature applied. So, increase in temperature result in increase in kinetic energy which reduces the inter-molecular force of fluid and as a result liquid expands.

Liquid contracts on cooling.

Fall in temperature results in reduced kinetic energy which in turn also decreases the kinetic energy of the molecules of liquid thereby increasing the inter-molecular force of attraction of fluid that's why liquid contracts on cooling.

answer: option c. i.e. electric current flowing “downhill” from the negative electrode to the positive electrode in a battery

explanation:

the water analogy to the circuits define the pipes (water flows) to the electric current. now, we know that the electric current flows from the positive terminal to the circuit (as shown in the diagram attached).

hence, option c is the correct answer.

it is the second option.