Venus has about 80 percent of earth's mass and about 95 percent of earth's radius. your weight on venus will be

Working Principle: Newton's Gravitational Law

F = G*M*m/R^2

where: 

F= gravitational force
G = gravitational constant (6.674×10-11 Newtons x meters2 / kilograms2)
M = planet mass
m = subject mass
r = distance between to objects

Given: 
Earth's Mass (M1) = 5.972x10^24 kg
Eath's Radius (R1) = 6371 km = 6371000 meters
Venus' Mass (M2) = 0.8*( 5.972x10^24 kg) =4.7776x10^24 kg
Venus' Radius (R2) = 0.95*(6371 km) = 6052.45 km = 6052450 meters

Required: Mass on Venus (m2)

Solution:
We know that F1 and F2 for both planets are the same. Thus we equate the formula, we get

G*M1*m1/(R1^2) = G*M2*m2/(R2^2)

G is common for both, so we eliminate G
M1*m1/(R1^2) = M2*m2/(R2^2)
 (5.972x10^24)*m1/(6371000^2) = (4.7776x10^24)*m2/(6052450^2)

Solving for m2,
m2 = 0.88*m1

Therefore, your mass on Venus is 88% of that your mass on Earth.

ANSWER: Mass on Venus is 88% of your mass on Earth

The rocks expand when there hot/warm  and contract when they are cold.