boy
chemical
chemist
chemistry
child
class
classroom
clock
deadline
dish
education
experiment
experimenting
fluid
glass
hourglass
kid
late
learning
lesson
liquid
management
missing
petri
pouring
punctual
punctuality
research
sample
sand
sandglass
school
schoolboy
science
scientific
scientist
secondary
student
study
studying
substance
teen
teenager
test
testing
time
timer
tube
tubes