I have to do a science fair project and my science teacher told me to ask a plumber and there are no plumbers in my neighborhood so I went on here and my question that I wanted to ask you was:how much water does an average person use when they take a bath and when they take a shower?

I'm not a plumber, but I am a scientist. That's a deceptively complicated question. Every person is different in their bathing habits - differences in depth of the bath water and size of the tub, as well as length of the shower will affect the amount of water used.

I recommend using yourself and any willing friends/family members for a little experiement. Fill your tub with the amount of water you would normally use for a bath. Measure the depth of the water (without anything else in the tub). The next day, take a normal shower with the drain stopped. Measure the depth of that water. Compare the two and you'll know whether you use more water in a bath or in a shower. You'll need more people than just you to get a decent sample of the population.

I'm not a plumber, but I am a scientist. That's a deceptively complicated question. Every person is different in their bathing habits - differences in depth of the bath water and size of the tub, as well as length of the shower will affect the amount of water used.

I recommend using yourself and any willing friends/family members for a little experiement. Fill your tub with the amount of water you would normally use for a bath. Measure the depth of the water (without anything else in the tub). The next day, take a normal shower with the drain stopped. Measure the depth of that water. Compare the two and you'll know whether you use more water in a bath or in a shower. You'll need more people than just you to get a decent sample of the population.

Thank you so much!

Even though this is a science question, I moved your question to Plumbing to catch the eyes of our plumber members. Want me to move it back to Ecology or to an Education/Science board?

As a general rule a shower will use less water because the flow is regulated to be no more than 2.5 GPM, at least in newer houses. Tub faucets are not regulated. However, as kmcar529 noted, it depends on how long you run the shower. If you use an equivalent time, assuming same system and pressure, you will use more water in a bath as a typical bath faucet will produce 4-5 GPM.

You Use Less Energy Taking a Shower Than a Bath.

It depends on your shower head and whether it has a flow restrictor in it and how long you shower.
If your home was built before 1992, chances are your showerheads put out about five gallons of water per minute (gpm). Multiply this by the number of minutes you're in the shower, and the water adds up fast!
An average bath requires 30-50 gallons of water. The average shower of four minutes with an old shower head uses 20 gallons of water. With a low-flow shower head, only 10 gallons of water is used.

To test the amount of water used in a shower vs. a bath is to put the plug in the bath next time you take a shower (but not a stand-alone shower as you might spill over the lower shower wall).
After you've showered, see how much the tub filled up.
If there is less water than you would usually have in a bath, then you will probably save money by taking a shower instead of a bath.
Does this answer your question? Cheers, Tom