When water freezes, it's volume INcreases, which naturally results in a DEcrease in it's density. That's why cubes and bergs float.
I'm pretty sure that water is the only known substance that behaves this way. Which is lucky for us, because if it didn't, then life on Earth would be impossible. Oceans and lakes would freeze from the bottom up. Once! And then they would never thaw, because the sun could never cut through the layer of warm water on top, to melt the ice below.
We use the formula of the half-life to calculate for the remaining U-238 after 4.5 billion years. The formula is expressed as A = A₀ (1/2)^(t/h) where A is the final amount, A₀ is the initial amount of the substance, t is the time and h is the half-life of the substance wherein for U-238 h is equal to 4.47 billion years.
<span>A = A₀ (1/2)^(t/h)
</span>A = 50 (1/2)^(4.5 / 4.47)
A = 24.88 g
... cloak of invisibility spread over it.
Electromagnetic Waves: This type of wave requires no medium (substance) to travel through.
An insulator is a material that provides resistance to the flow of electric current. Insulators include rubber, plastic, glass since they do not allow electricity to flow through them.
