<P> In materials science and engineering, the pascal measures the stiffness, tensile strength and compressive strength of materials . In engineering use, because the pascal represents a very small quantity, the megapascal (MPa) is the preferred unit for these uses . </P> <Table> Approximate Young's modulus for common substances <Tr> <Th> Material </Th> <Th> Young's modulus </Th> </Tr> <Tr> <Td> nylon 6 </Td> <Td> 2--4 GPa </Td> </Tr> <Tr> <Td> hemp fibre </Td> <Td> 35 GPa </Td> </Tr> <Tr> <Td> aluminium </Td> <Td> 69 GPa </Td> </Tr> <Tr> <Td> tooth enamel </Td> <Td> 83 GPa </Td> </Tr> <Tr> <Td> copper </Td> <Td> 117 GPa </Td> </Tr> <Tr> <Td> structural steel </Td> <Td> 200 GPa </Td> </Tr> <Tr> <Td> diamond </Td> <Td> 1220 GPa </Td> </Tr> </Table> <Tr> <Th> Material </Th> <Th> Young's modulus </Th> </Tr> <Tr> <Td> nylon 6 </Td> <Td> 2--4 GPa </Td> </Tr>

Name the quantity whose one of the units is pascal