A penetrometer is a device to test the strength of a material.
There are many types of penetrometer designed to be used on soil. They are usually round or cone shaped. The penetrometer is dropped on the test subject or pressed against it and the depth of the resulting hole is measured. The measurements find whether the soil is strong enough to build a road on. Scientists also use a penetrometer to measure how much moisture is in soil. Penetrometers are used by space probes such as the Cassini–Huygens probe, to measure the amount of moisture in soil on other planets. Penetrometers are furthermore used in glaciology to measure the strength and nature of materials underlying a glacier at its bed.
British horse racing courses have been required, since 2009, to report the readings obtained using a penetrometer designed by Cranfield University and TurfTrax, known as the GoingStick, on each day of a race meeting.
A penetrometer may be used in botany to find the toughness of a leaf by measuring the force needed to punch a hole of a certain size through the leaf.
Penetrometers are used for objective evaluation of food products. Penetrometers, equipped with a plunger and a needle or cone, penetrate food samples through gravitational force for a selected period of time. The distance the test device penetrates into the sample is measured to determine the relative tenderness of the samples such as baked products and gels. 
- University of Arizona document, "An impact penetrometer for a landing spacecraft."
- Picture of a penetrometer from the European Space Agency (ESA)
- Proceedings of the Entomological Society of Washington, "A portable penetrometer for measuring leaf toughness in insect herbivory studies."
- "GoingStick Average Readings" (PDF). British Horseracing Authority. March 2014. Retrieved 22 November 2015.
- "Fruit Ripeness Testing by Wagner Instruments". Fruit Test.
- "Foods: Experimental Perspectives, 8th Edition Margaret McWilliams, Ph.D., R.D., Professor Emeritus, California State University, Los Angeles, 2017, Pearson". Missing or empty