There are measurements smaller than a meter. There is the centimeter (cm), milimeter (mm), and micrometer (um). They can use many different things to measure objects. Most rulers come with inches along one side and centimeter/milimeters along the other.
Meters should be used to measure the length of a tennis court in metric units.
An ordinary size book should be measured in centimeters.
kilometers
The scientist should use a light microscope.
Absolutely. Photographic light meters are designed to measure light for photographic exposure (in a film-speed/shutter-speed/aperture combination), but many hand-held photo light meters can measure light in footcandles, which is a common scale. If you look on places like eBay, you can find inexpensive, digital, brand new meters which read out in Lux or Lumens. Some may read in footcandles as well. It's not difficult to convert from one measure to another (there should be internet calculators which would do it easily).
You should be on the moving object
meters-centimeters are really small, about a third of an inch. Meters are about a yard. Would you measure a pool in thirds of inches or yards? Exactly
Meters should be used to measure the length of a tennis court in metric units.
A pH meter
A pH meter
An ordinary size book should be measured in centimeters.
A pH meter
You should use a ruler to measure a fork. Once you have the measurement, it's probably most convenient to describe it in units of centimeters or millimeters, but meters will also work just fine.
Meters if you're using the metric system. Otherwise use feet.
Length is measured in meters in the metric system.
A Stop Watch
try out the ruler on google earth